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A three compartment solar formic acid generator was built using a Sn on Cu foam cathode and NiFe anode. A bipolar combination of a Fumasep FAD-PET-75 and Nafion 117 membrane was mounted between anode and middle compartment, which was filled with Amberlyst 15H ion exchanger beads. A Fumasep FAD-PET-75 membrane separated the middle compartment from the cathode. The generator was powered with a photovoltaic panel and fed with gaseous CO2 and water. Diluted formic acid solution was produced by flowing water through the middle compartment. Common PV-EC devices are operated using aqueous electrolyte and produce aqueous formate. In our PV-EC device, formic acid is produced straight away, avoiding the need for downstream operations to convert formate to formic acid. The electrolyser was matched with solar photovoltaic cells achieving a coupling efficiency as high as 95%. Our device produces formic acid at a faradaic efficiency of ca. 31% and solar-to-formic acid efficiency of ca. 2%. By producing formic acid from CO2 and water without any need of additional chemicals this electrolyser concept is attractive for use at remote locations with abundant solar energy. Formic acid serves as a liquid renewable fuel or chemical building block.

A reflowing photoresist and oxidation smoothing process is used to fabricate ultra-high-Q silicon microring resonators based on multimode rib waveguides. Over a wide range of wavelengths near 1550 nm, the average Q-factor of a ring with 1.2-μm-wide waveguides reaches up to 1.17 × 106, with a waveguide loss of approximately 0.28 dB/cm. For a resonator with 1.5-μm-wide waveguides, the average Q-factor reaches 1.20 × 106, and the waveguide loss is 0.27 dB/cm. Moreover, we theoretically and experimentally show that a reduction in the waveguide loss significantly improves the conversion efficiency of four-wave mixing. A high four-wave mixing conversion efficiency of −17.0 dB is achieved at a pump power of 6.50 dBm.

The present study aimed to investigate the feasibility of blended amine absorbents in improving the CO2 alkanolamine-based absorption of multicycle integrated absorption–mineralization (multicycle IAM) under standard operating conditions (20–25 °C and 1 atm). Multicycle IAM is a promising approach that transforms CO2 emissions into valuable products such as carbonates using amine solvents and waste brine. Previously, the use of monoethanolamine (MEA) as an absorbent had limitations in terms of CO2 conversion and absorbent degradation, which led to the exploration of blended alkanolamine absorbents, such as diethanolamine, triethanolamine, and aminomethyl propanol (AMP) combined with MEA. The blended absorbent was evaluated in terms of the absorption performance and carbonate production in continuous cycles of absorption, precipitation/regeneration, and preparation. The results showed that the fourth cycle of the blend of 15 wt.% AMP and 5 wt.% MEA achieved high CO2 absorption and conversion efficiency, with approximately 87% of the absorbed CO2 being converted into precipitated carbonates in 43 min and a slight degradation efficiency of approximately 45%. This blended absorbent can improve the efficiency of capturing and converting CO2 when compared to the use of a single MEA, which is one of the alternative options for the development of CO2 capture and utilization in the future.

We have studied the laser pulse shape dependence of the conversion efficiency of λ = 1.03 μm laser pulse energy into 13.5 nm extreme ultraviolet (EUV) emission from a Sn laser-produced plasma. Laser pulses of arbitrary temporal shape ranging from hundreds of picoseconds to several nanoseconds were generated using a programmable pulse synthesizer based on a diode-pumped chirped pulse amplification Yb: YAG laser. Measurements show that the conversion efficiency favors the use of nearly square pulses of duration longer than 2 ns, in agreement with hydrodynamic/atomic physics simulations. A 35% increase in conversion efficiency was obtained when Q-switched pulses were substituted by square pulses of a similar duration. Experiments conducted irradiating a Sn target with a sequence of two time-delayed 250 ps pulses showed a 30 percent increase in the EUV yield respect to a single pulse of the same total energy when the pulse separation was optimum at 2.1 ns. This suggests that re-heating of the plasma with delayed laser pulses could be used to improve the EUV yield. The spectroscopic characterization of EUV emission and in-band EUV images that characterize the source size are also presented.

The conversion efficiency of a harvesting component can hinder device self-sustainability. Countering this inefficiency can be a rigorous task that requires either a modified input waveform at the harvesting component or an improved design of the harvesting component itself. This paper considers a selective orthogonal frequency division multiplexing (OFDM) system that is designed for simultaneous wireless information and power transfer (SWIPT). This paper introduces an enhanced transmitter architecture designed to condition the transmit signal for improved conversion efficiency. Leveraging the structure of the OFDM signal, the cyclic prefix plus a portion of the information signal are conditioned and used for harvesting. Then, a rectifier model and prototypes are designed to further improve conversion efficiency. System performance is evaluated with the analytical derivation of the rate-energy (R-E) tradeoff and an optimized transmission strategy for system self-sustainability. Monte Carlo simulations show increased energy gains and full self-sustainability with the introduction of signal conditioning.

Silicon Germanium (SiGe) solar cells with different bandgaps are used in the fabrication of the crystalline-Si/SiGe (c-Si/SiGe) double-junction cell in order to enhance the performance of the c-Si single devices. The new device is simulated with SCAPS-1D by placing the c-Si junction on the top of the SiGe solar cell. Through this simulation, one can assess the performance of the c-Si/SiGe double-junction device. The upper c-Si cell achieved an efficiency of 16.66% with 40.5 $\mu \text{m}$ total thickness, while the lower cell SiGe achieved ~ 19% efficiency. By analyzing the current matching between both cells at different bandgaps for SiGe cell (1.097 eV, 1.016 eV, and 0.928 eV), a mismatch is found. But, when applying 0.882 eV bandgap for the lower cell with absorber thicknesses of 110, 100, 90, and 6.2 $\mu \text{m}$ , a matching is obtained between the two junctions. The efficiency of the designed cell is found ~ 24.7%, with a maximum current density of 30.25 mA/cm2, achieved at an open circuit voltage of 1.01 V and a total thickness of 57.2 $\mu \text{m}$ . These results indicate that the double-junction device significantly exceeds the device performance by 7.6% with equal thickness of the optimized single-junction c-Si solar cell.

This paper provided a method to improve the conversion efficiency and lessen the lift-off effect of spiral coil electromagnetic acoustic transducer (EMAT) for some specific situations, for example, irregular sample surface, online inspection and varying coating. Moreover, a new evaluation method for the performance of EMAT is proposed. To study the effect of the structural parameters on the performance of EMAT, the orthogonal test method with five factors and four levels is employed. Consequently, the degree of five factors on the lift-off performance and the theoretical maximum value of amplitude are obtained. The results show almost all factors have an obvious impact on the theoretical maximum value of amplitude, while only the magnet-to-coil distance can affect the lift-off performance effectively. The experiment results well agree with the numerical results, in which the improvement of the lift-off performance and the theoretical maximum value of amplitude is 31.94% and 78.79% respectively. In addition, the conversion efficiency of EMAT is increased by 125% when the lift-off is 1 mm. These imply the performance of spiral coil electromagnetic acoustic transducer is improved dramatically and the detectable lift-off is increased as well.

Fluorescent nanodiamonds containing negatively-charged nitrogen-vacancy (NV−) centers are promising for a wide range of applications, such as for sensing, as fluorescence biomarkers, or to hyperpolarize nuclear spins. NV− centers are formed from substitutional nitrogen (P1 centers) defects and vacancies in the diamond lattice. Maximizing the concentration of NVs is most beneficial, which justifies the search for methods with a high yield of conversion from P1 to NV−. We report here the characterization of surface cleaned fluorescent micro- and nanodiamonds, obtained by irradiation of commercial diamond powder with high-energy (10 MeV) electrons and simultaneous annealing at 800 ∘C. Using this technique and increasing the irradiation dose, we demonstrate the creation of NV− with up to 25% conversion yield. Finally, we monitor the creation of irradiation-induced spin-1 defects in microdiamond particles, which we associate with W16 and W33 centers, and investigate the effects of irradiation dose and particle size on the coherence time of NV−., acceptedVersion

Organic–inorganic perovskite photovoltaics have now achieved power conversion efficiencies at par with silicon devices on a lab-scale. To enable industrial application of the technology, developing a perovskite deposition route compatible with scalable, large-area deposition methods, which exploits safer processing solvents and is robust to variations of the processing parameters, particularly humidity, is highly demanded. To satisfy such constraints altogether, here we introduce a lead iodide–hydroiodic acid–water precursor (PbI2–HI–H2O) that enables the scalable deposition of methylammonium lead triiodide (MAPbI3) films from a safer solvent (acetonitrile – ACN) in a wide range of high moisture levels, spanning from 50 to 80% relative humidity. When exposed to a methylamine (MA) gas flow the PbI2–HI–H2O precursor readily converts to specular perovskite films. If heated, the PbI2–HI–H2O film can be easily reverted to PbI2, further enabling the implementation of two step deposition methods. Our process was tested in an inverted solar cell configuration achieving stabilized power conversion efficiencies of 14% with minimal annealing requirements. Our findings demonstrate an appealing route for a large-area compatible manufacturing of hybrid perovskite photovoltaics in air, at high moisture levels, based on solvents of reduced hazard.

Five novel D-?-A structured pyridinium based compounds, bearing different electron-donating units were synthesized, minutely characterized, and their solvatochromic and electronic properties were investigated. Subsequently, these compounds were added to a liquid electrolyte in order to enhance the photovoltaic performance of the N719-sensitized solar cell. It was demonstrated that the utilization of all compounds improved the conversion efficiency, compared to the reference solar cell comprised of plain liquid electrolyte. The photovoltaic performance of the fabricated DSSC depended of the electron-donating moiety of the synthesized compound. The highest photovoltaic conversion efficiency of 4.11% was obtained for DSSC with the compound bearing the 4-(N,N-dimethylamino)phenyl group. © 2022, Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja, MPNTR: 451–03–68/2022–14/200026, 451–03–68/2022–14/200135, 451–03–68/2022–14/200287, This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Contract No. 451–03–68/2022–14/200287, 451–03–68/2022–14/200135 and 451–03–68/2022–14/200026).

For more than 2 decades, extensive research has been done in the field of Dye-Sensitized Solar Cells (DSSCs) due to their low cost, easy preparation methodology, less toxicity, and ease of production. In this work, the performance of DSSCs containing different particle sizes is studied. N2-doped TiO2 was prepared by the sol-gel method, controlling the particle size through the addition of different H2O/Ti mole ratios R = 0, 20, 30, and 40. The dried samples at 100°C were characterized by X-ray diffraction, Optical Properties, High-Resolution Transmission Electron Microscope, Scanning Electron Microscope, Fourier-Transform Infrared Spectroscopy, N2-Adsorption-Desorption Isotherm, Raman Spectroscopy, and Dynamic Light Scattering (DLS). DLS results show that the size of TiO2 decreases as the H2O/TiO2 content increases from 0 to 40. It is found that TiO2 nanoparticles with smaller particle size distribution has the lowest conversion efficiency of 0.95% with H2O/Ti ratio = 40, and the photoelectrode with higher size has a conversion efficiency of 1.59% for the water-free sample. This could be explained as the larger particles have better dye adsorption, indicating that it has an effective surface area for greater photon absorption and electron-hole generation. The results also indicate that trimodal distribution with larger size also absorbs different wavelengths due to the broad distribution of the particle size.

In this paper, germanium-based solar cells were designed based on germanium (Ge) materials, and the cross-cone (CC) nanostructures were used as the absorber layer of the solar cells. The optical path inside the absorber layer was increased by microstructure reflection, thereby increasing the absorption efficiency of the germanium-based solar cell. The reflectivity, transmittance, electric field and magnetic field of the corresponding position of the device were simulated and calculated by the finite difference time domain (FDTD) method. By simulating doping and simulating the external potential difference, the short-circuit current density (JSC), open-circuit voltage (VOC), output power and photoelectric conversion efficiency (η) of the device were calculated. The study found that for the entire study wavelength range (300–1600 nm), the transmittance of the device was close to none, and the average light absorption rate under air mass 1.5 global (AM1.5G) was 94.6%. In the light wavelength range from 310 nm to 1512 nm with a width of 1201 nm, the absorption rate was greater than 90%, which is in line with the high absorption of the broadband. Among them, the absorption rate at 886 nm reached 99.84%, the absorption rate at 1016 nm reached 99.89%, and the absorption rate at 1108 nm reached 99.997%, which is close to full absorption. By exploring the electrical performance of the device under different Ge nanostructure parameters, a germanium-based solar cell device under the nanocross-cone absorption structure array with both high-efficiency light absorption and excellent electrical performance was finally obtained. The study shows that the VOC of its single-junction cell was 0.31 V, JSC reached 45.5 mA/cm2, and it had a fill factor (FF) of 72.7% and can achieve a photoelectric conversion efficiency of 10.3%, surpassing the performance of most Ge solar cells today.

An analytical model is used to describe the electrical characteristics of a dual-junction tandem solar cell performing with a conversion efficiency of 32.56% under air mass 1.5 global (AM1.5G) spectrum. The tandem structure consists of a thin heterojunction top cell made of indium gallium phosphide (InGaP) on gallium arsenide (GaAs), mechanically stacked on a relatively thick germanium (Ge) substrate, which acts as bottom cell. In order to obtain the best performance of such a structure, we simulate for both the upper and lower sub-cell the current density–voltage, power density–voltage, and spectral response behaviors, taking into account the doping-dependent transport parameters and a wide range of minority carrier surface recombination velocities. For the proposed tandem cell, our calculations predict optimal photovoltaic parameters, namely the short-circuit current density (J sc ), open-circuit voltage (V oc ), maximum power density (P max ), and fill factor (FF) are J sc = 28.25 mA/cm 2 , V oc = 1.24 V, P max = 31.64 mW/cm 2 , and FF = 89.95%, respectively. The present study could prove useful in supporting the design of high efficiency dual junction structures by investigating the role of different materials and physical parameters.

We numerically investigate the conversion of solar energy into chemical energy by integrated photo-electrochemical (IPEC) devices and assess their response to time-dependent changes in the boundary conditions and the material properties. We focus on a device architecture which uses concentrated solar irradiation to reduce the use of rare and expensive components such as light absorbers and catalysts. For practical usability of IPEC devices, it is of particular importance that the device operates with stable efficiency and production rates. Variations in the operating conditions, resulting, for example, from degradation of the materials over the lifetime and from the daily and seasonal changes in incoming irradiation, pose a challenge for the stable and secure production of fuel from such devices. To tackle these issues, we develop performance optimization strategies utilizing device design, component and material choice, and adaptation of operational conditions. Degradation effects can be alleviated (3-21% improvement in production) by dynamically adapting the input water flow rates. The water mass flow controller acts as an optimum operating point tracker for the IPEC device eliminating any need for additional, external power electronics (such as a dc-dc based maximum power point tracker). Mass flow rate adaptation can further be used to alleviate higher frequency variations given by the per-minute and daily variation in the irradiation. A stabilized efficiency and hydrogen production for the day can be achieved with mass flow controlling, with a production increase in the range of 1-6%. The developed strategies highlight that the design of an IPEC device needs to consider the realistic operation of the IPEC during the complete life. The developed strategies show that mass flow control allows for a more dynamic PEC operation and is a powerful tool to ensure robust and efficient device operation and to allow for alleviation of degradation effected performance reduction while excluding any external power electronics.

Energy scavenging is a promising technique for micro-devices such as wireless sensor networks (WSNs). Radio frequency (RF) is considered a sustainable source that can be utilized and harvested due to its important features. The essential goal of this study was designing and investigating a wide input power range through a theoretical and simulation work for the 900 MHz frequency band with acceptable efficiency. In this work, we investigated both the low input power and the high input power range circuits; the two circuits were combined to achieve the goal of the wide input power range. L impedance matching elements were used to perform the desired matching between the power source and the circuit to reduce the reflected power resulted in enhanced RF-DC conversion efficiency. 60 % was the peak efficiency for the proposed design at 0 dBm with the output voltage of 16.56 V, and a generated current of 1.39 mA for the load of 12KΩ.

In this paper, the effect of diffraction grating and engineering absorber and back surface field (BSF) layers on performance of a single-junction polycrystalline cadmium sulfide/cadmium telluride (CdS/CdTe) solar cell have investigated. At first, the electrical characteristics of reference CdS/CdTe solar cell is simulated and validated with experimental data of fabricated CdS/CdTe solar cell. In order to improve the maximum efficiency, a new structure with diffraction grating and engineering absorber and back surface field layers is presented. Furthermore, the effect of carrier lifetime variation in the absorber layer on the conversion efficiency of solar cell was investigated. It is found that diffraction grating and engineering absorber and back surface field layers can increase the conversion efficiency of the solar cell by about 1.02% and 6% compared with reference cell, respectively. Under global AM 1.5 conditions, the open circuit voltage, short circuit current density, fill factor and conversion efficiency of optimized solar cell structure are 1114 mV, 25.35 mA/cm2, 0.8856 and 25.022%, respectively.

In this paper, we review the state of the art of mode selective, integrated sum-frequency generation devices tailored for quantum optical technologies. We explore benchmarks to asses their performance and discuss the current limitations of these devices, outlining possible strategies to overcome them. Finally, we present the fabrication of a new, improved device and its characterization. We analyse the fabrication quality of this device and discuss the next steps towards improved non-linear devices for quantum applications., Comment: 20 pages, 10 figures

Aim of this work is the evaluation of thermal behavior and performance of a conventional diesel oxidation catalyst (DOC) installed on an engine operating in dual-fuel diesel-methane conditions following a well-defined methodology conceived ad hoc. A catalyst was sized, realized, and instrumented with five thermocouples. Once mounted along the engine exhaust line, the test was run in order to determine several parameters characterizing the DOC behavior, such as downstream emission levels, conversion efficiency, thermal behavior, and lightoff temperature. Tests have been performed varying the engine speed and substitution ratio in order to analyze the effect of these operating parameters on the behavior of the catalyst. The results indicate that, in dual-fuel conditions, the oxidation of species takes place in zones closer to the exit section, determining temperatures higher than those measured in conventional diesel combustion conditions at the same engine load. The light-off temperatures related to the conversion efficiency of unburned hydrocarbons and carbon monoxide both increase in dual-fuel conditions. The effect of substitution ratio results from the combined effects on combustion development together with engine-out concentration of long-chain and short-chain unburned hydrocarbons. The resulting effect is, on one hand, the reduction of unburned hydrocarbons light-off temperature as methane increases. On the other hand, carbon monoxide light-off temperature increases as methane increases due to the increased amount of engine-out hydrocarbons emissions. The reduction of engine speed determines the reduction of the temperature of the exhaust gases to the extent that the light-off conditions are sometimes not reached. Finally, a sensitivity analysis base on neural networks showed that, while less variables are sufficient for describing the behavior, in terms of carbon monoxide conversion efficiency, of a DOC mounted on an engine working in dual-fuel diesel-methane conditions, in case of unburned hydrocarbons conversion a set of more variables is required.

Second harmonic generation has been widely applied in various fields. High second harmonic intensity can facilitate optical imaging, signal sensing, and detection. Thus, enhancing the intensity of the second harmonic is a significant work. However, changing the external character of crystal or increasing the pump light intensity to improve the intensity of the second harmonic is not always advisable in some applications, such as bioimaging, biopsies, etc. Here, we implemented a noninvasive method that constructs a specific spatial distribution field via a scattering medium to realize a high enhancement of second harmonic intensity. We studied that different scattering mediums exerted the influence on the optimal enhancement effect of second harmonic. It was found that choosing an appropriate scattering medium can greatly enhance the intensity of the second harmonic. The results can offer a helpful value for second harmonic applications such as bioimaging, sensing, and optical frequency conversion.

The modulation strategy, proposed in the technical literature to control the three-switch double-input bidirectional DC-DC converter, forces the converter itself to work in Continuous Conduction Mode at low-load and therefore efficiency drops significantly. In this paper, a novel modulation strategy, exploiting Discontinuous Conduction Mode at low-load, is proposed. Converter efficiency increase is evaluated with simulations in MATLAB/Simulink Plecs environment. Finally, the control is validated with experimental tests.

One of the main factors affecting the performance of quantum dot sensitized solar cells (QDSSCs) is charge recombination caused by surface traps. It is important to passivize the surface traps of the synthesized QDs as much as possible in order to raise the power conversation efficiency (PCE). Therefore, in this study, the effects of chloride passivation on the performance of CdSeTe QDSSCs were tested. CdSeTe QDs synthesized by the hot injection method were passivized with chlorine ions in different proportions (10-70%) by mass and CdSeTe(Cl) QDSSCs were designed. In order to detect the effects of chloride treatment, chloride passivation was applied to CdSeTe QDs with different growth time. The absorbance and emission characterizations of the synthesized CdSeTe and CdSeTe(Cl) QDs were removed, HR-TEM and X-ray diffraction (XRD) studies were performed. Photovoltaic, incident-photo-to-carrier conversation (IPCE), electrochemical impedance spectroscopy (EIS) measurements were performed for all designed CdSeTe QDSSCs. As a result of the analyses, it was determined that chloride treatment increased the PCE of CdSeTe (Cl) QDSSCs by 2.456 times compared to untreated CdSeTe QDSSCs. The average value of PCE for CdSeTe(Cl) (60% Cl) (5 min) QDSSCs was 3.379 +/- 0.08%, while J(SC) and V-OC values were measured as 10.048 mA/cm(2) and 0.664 V, respectively. Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [217M897] This study was financially supported by Scientific and Technological Research Council of Turkey (TUBITAK), project number 217M897. WOS:000566928700010 2-s2.0-85086667303

Коваленко Артем Евгеньевич, аспирант кафедры менеджмента, Южно-Уральский государственный университет (г. Челябинск), insmarkets@gmail.com Artoym E. Kovalenko, postgraduate student, Department of Management, South Ural State University, Chelyabinsk, insmarkets@gmail.com Статья посвящена рассмотрению преобразования показателей оценки экономической эффективности технологий интернет-маркетинга в малом бизнесе. Выделена исследовательская проблема, основанная на противоречии между разнообразием показателей оценки эффективности интернет-маркетинговой деятельности и потребностью малых организаций в оценке экономической эффективности. Выполнен анализ роли интернет-маркетинга как свойства современного маркетинга на основе методологии входящего маркетинга. Процесс оценки экономической эффективности интернет-маркетинговой деятельности описан с позиций определения стоимостных и количественных характеристик информационного потока интернет-маркетинга. Рассмотрена специфика деятельности внешних маркетинговых экспертных субъектов в процессе внедрения технологий интернет-маркетинга. Сформирован вариант взаимодействия показателей оценки эффективности интернет-маркетинга и показателей оценки экономической эффективности маркетинговой деятельности на основе исследования свойств информационного потока интернет-маркетинга. Составлено математическое описание в виде системы неравенств, отражающих количественные и стоимостные характеристики информационного потока интернет-маркетинга. Разработана практическая иллюстрация преобразования показателей оценки экономической эффективности технологий интернет-маркетинга для предприятий малого бизнеса в виде расчетной таблицы. The article is devoted to the consideration of the conversion of indicators of the cost-benefit analysis of Internet marketing technologies in small businesses. A research problem based on the contradic-tion between the variety of performance indicators of Internet marketing activities and the need for small organizations to do a cost-benefit analysis is highlighted. The analysis of the role of Internet mar-keting as a property of modern marketing based on the methodology of inbound marketing is carried out. The process of the cost-benefit analysis of Internet marketing activities is described from the stand-point of determining the cost and quantitative characteristics of the Internet marketing informational flow. The specifics of the activities of external marketing expert entities in the process of implementing Internet marketing technologies is considered. An option for the interaction of the performance indica-tors of Internet marketing and indicators of cost-benefit analysis of marketing activities based on a study of the properties of the Internet marketing informational flow is formed. A mathematical description in the form of a system of inequalities that reflect the quantitative and cost characteristics of the Internet marketing informational flow is compiled. A practical illustration of the conversion of indicators of the cost-benefit analysis of Internet marketing technologies for small business enterprises in the form of a calculation table is developed. Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 19-310-90021. The research has been carried out with the financial support of the Russian Foundation of Fundamental Research in the framework of scientific project No. 19-310-90021.

In early 2017, the world record efficiency for single-junction crystalline silicon (c-Si) solar cells was achieved by merging amorphous silicon (a-Si:H)/c-Si heterojunction technology and back-contact architecture. However, to fabricate such silicon heterojunction interdigitated back-contact (SHJ-IBC) solar cells, complex a-Si:H patterning steps are required to form the interdigitated a-Si:H strips at the back side of the devices. This fabrication complexity raises concerns about the commercial potential of such devices. In this work, a novel process scheme for a-Si:H patterning using damage-free laser ablation is presented, leading to a fast, simple and photolithography-free emitter patterning approach for SHJ-IBC solar cells. To prevent laser-induced damage to the a-Si:H/c-Si heterocontact, an a-Si:H laser-absorbing layer and a dielectric mask are deposited on top of the a-Si:H/c-Si. Laser ablation only removes the top a-Si:H layer, reducing laser damage to the bottom a-Si:H/c-Si heterocontact under the dielectric mask. This dielectric mask is a distributed Bragg reflector (DBR), resulting in a high reflectance of 80% at the laser wavelength and thus providing additional protection to the a-Si:H/c-Si heterocontact. Using such simple a-Si:H patterning method, a proof-of concept 4-cm(2) SHJ-IBC solar cell with an efficiency of up to 22.5% is achieved. The authors gratefully acknowledge the financial support of IMEC's Industrial Affiliation Program for Si-PV. This project has also received funding from the European Union's Horizon 2020 Research and Innovation Programme under grant agreement no. 727523 (NextBase).

A bottom-reflectivity-enhanced ultra-thin nanowire array solar cell is proposed and studied by 3D optoelectronic simulations. By inserting a small-index MgF2 layer between the polymer and substrate, the absorption is significantly improved over a broad wavelength range due to the strong reabsorption of light reflected at the polymer/MgF2 interface. With a 5 nm-thick MgF2 layer, the GaAs nanowire array solar cell with a height of 0.4&ndash, 1 &mu, m yields a remarkable conversion efficiency ranging from 14% to 15.6%, significantly higher than conventional structures with a much larger height. Moreover, by inserting the MgF2 layer between the substrate and a part of the nanowire, in addition to between the substrate and polymer, the absorption of substrate right below the nanowire is further suppressed, leading to an optimal efficiency of 15.9%, 18%, and 5.4% for 1 &mu, m-high GaAs, InP, and Si nanowire solar cells, respectively. This work provides a simple and universal way to achieve low-cost high-performance nanoscale solar cells.

The present paper deals with the development of a simulation model for predicting the performances of a solar photovoltaic (PV) system operating under current meteorological conditions at the site location. The proposed model is based on the cell equivalent circuit including a photocurrent source, a diode, a series and shunt resistances. Mathematical expressions developed for modeling the PV generator performances are based on current-voltage characteristic of the considered modules. The developed model allows the prediction of PV cell (module) behavior under different physical and environmental parameters. The model can be extended to extract physical parameters for a given solar PV module as a function of temperature and solar irradiation. A typical 260 W solar panel developed by LG Company was used for model evaluation using Newton-Raphson approach under MATLAB environment in order to analyze its behavior under actual operating conditions. Comparison of our results with data taken from the manufacturer’s datasheet shows good agreement and confirms the validity of our model. Hence, the proposed approach can be an alternative to extract different parameters of any PV module to study and predict its performances.

The use of eco-friendly energy in the offshore plant system is expanding because conventional generators are operated by fossil fuel or natural gas. Eco-friendly energy, which replaces existing power generation methods, should be capable of generating the power for lighting protection equipment, airborne fault indication, parameter measurement, and others. Most of the eco-friendly energy used in offshore plant facilities is solar and wind power. In the case of using photovoltaic power, because the structure must be constructed based as flat solar panels, it can be damaged easily by the wind. Therefore, there is a need for a new generation system composed of a spherical structure that does not require a separate structure and is less influenced by the wind. Considering these characteristics, in this study we designed, fabricated, and tested a unit that could provide the most efficient spherical photovoltaic power generation considering wind direction and wind pressure. Our test results indicated that the proposed system reduced costs because it did not require any separate structure, used eco-friendly energy, reduced carbon dioxide emissions, and expanded the proportion of eco-friendly energy use by offshore plant facilities.

The behavior of InN/InxGa1-xN spherical quantum dots solar cell is investigated, considering the internal electric field induced by the polarization of the junction. In order to determine the position of the intermediate band (IB), we present an efficient numerical technique based on difference finite method to solve the 3D time-independent Schrodinger's equation in spherical coordinates. The resultant n × n Hamiltonian matrix when considering n discrete points in spatial direction is diagonalized in order to calculate energy levels. Thus, the interband and intersubband transitions are determined, taking into consideration the effect of the internal electric field, size dots, interdot distances, and indium content on the energy levels, optical transition, photo-generated current density, open-circuit voltage and power conversion efficiency of the QD-IBSCs.

Sweet potato (Ipomoea batatas L.) is a plant that needs full sun to grow and get optimum yield. It needs an engineering technology that is able to integrate plant and environment in order to overcome abiotic factors in Papua highland. This research aims to determine the growth, result and energy conversion efficiency conatined in the sweet potato by combining variety and different stake inclination angle. This research was conducted in Baliem valley of Jayawijaya district. The experimental design used was factorial group random design with three replications. The research result shows that to make plant more efficient in managing solar intensity in Papua highland, so it is advised to plant Cangkuang variety (broad leaf) and to use stakle with inclination angle of 60º and 90º.

Here, the authors studied a silicon-germanium (Si1-xGex) absorber layer for the design and simulation of an ultra-thin crystalline silicon solar cell using Silvaco technology computer-aided design. Seeking ways to design and fabricate solar cells using 100m thicker silicon substrates is the subject of intense research efforts among the photovoltaic (PV) community. The aim is to further reduce the substrate thickness to 20m without compromising the efficiency of the solar cell. A thin layer of SiGe film with the Ge composition of 15% has been introduced in this work that assists in absorbing the longer wavelength of the sunlight spectrum. The effects of the doping concentration and absorber layer thickness on the conversion efficiency have been examined. The simulated results exhibited significant enhancement in the sunlight absorption as compared to the reference structure based on crystalline silicon. The highest efficiency of 16.8% with an overall solar cell thickness of approximate to 26m has been observed. The proposed heterostructure solar cell design will support the industrial development of an efficient, low-cost, shorter energy payback time, and light-weight PV technology for its widespread implementation.

The photovoltaic (PV) system center inverter architecture comprises various conventional array topologies such as simple-series (S-S), parallel (P), series-parallel (S-P), total-cross-tied (T-C-T), bridge-linked (B-L), and honey-comb (H-C). The conventional PV array topologies under non-uniform operating conditions (NUOCs) produce a higher amount of mismatching power loss and represent multiple maximum-power-points (M-P-Ps) in the output characteristics. The performance of T-C-T topology is found superior among the conventional topologies under NUOCs. However, T-C-T topology’s main limitations are higher redundancy, more number of electrical connections, higher cabling loss, poor performance during row-wise shading patterns, and more number of switches and sensors for the re-configuration of PV modules. This paper proposes the various optimal hybrid PV array topologies to overcome the limitations of conventional T-C-T array topology. The proposed hybrid topologies are such as series-parallel-cross-tied (S-P-C-T), bridge-link-cross-tied (B-L-C-T), honey-comb-cross-tied (H-C-C-T), series-parallel-total-cross-tied (S-P-T-C-T), bridge-link-total-cross-tied (B-L-T-C-T), honey-comb-total-cross-tied (H-C-T-C-T), and bridge-link-honey-comb (B-L-H-C). The proposed hybrid topologies performance is evaluated and compared with the conventional topologies under various NUOCs. The parameters used for the comparative study are open-circuit voltage, short-circuit current, global-maximum-power-point (GMPP), local-maximum-power-point (LMPP), number of LMPPs, and fill factor (FF). Furthermore, the mismatched power loss and the conversion efficiency of conventional and hybrid array topologies are also determined. Based on the results, it is found that the hybrid array topologies maximize the power output by mitigating the effect of NUOCs and reducing the number of LMPPs.

The numerical modeling of a copper zinc tin sulfide (CZTS)-based kesterite solar cell is described in detail in this article. To model FTO/ZnO/CdS/CZTS/MO structured solar cells, the Solar Cell Capacitance Simulator-one-dimension (SCAPS-1D) program was utilized. Numerical modeling was used to estimate and assess the parameters of various photovoltaic thin film solar cells. The impact of different parameters on solar cell performance and conversion efficiency were explored. Because the response of a solar cell is partly determined by its internal physical mechanism, J-V characteristic characteristics are insufficient to define a device’s behavior. Regardless of the conviction in solar cell modeling, variable attributes as well as many probable conditions must be handled for simulation. Promising optimized results were obtained with a conversion efficiency of (η% = 25.72%), a fill factor of (FF% = 83.75%), a short-circuit current of (JSC = 32.96436 mA/cm2), and an open-circuit voltage of (VOC = 0.64 V). The findings will aid in determining the feasibility of manufacturing high-efficiency CZTS-based solar cells. First, in the SCAPS-1D environment, the impacts of experimentally constructed CZTS solar cells were simulated. The experimental data was then compared to the simulated results from SCAPS-1D. After optimizing cell parameters, the conversion efficiency of the improved system was observed to rise. The influence of system factors, such as the thickness, acceptor, and donor carrier concentration densities of the absorber and electron transport layers, and the effect of temperature on the efficiency of CZTS-based photovoltaic cells, was explored using one-dimensional SCAPS-1D software. The suggested findings will be extremely useful to engineers and researchers in determining the best method for maximizing solar cell efficiency, as well as in the development of more efficient CZTS-based solar cells.

Solar thermoelectric (TE) generators can directly harness solar energy by generating electrical power and producing hot water for regions with unreliable electricity supply. This article investigates the performance of a photovoltaic-assisted solar parabolic dish thermoelectric system used to produce thermal and electric energy. The experimental setup comprises two photovoltaic (PV) modules, six thermoelectric power modules, a parabolic dish concentrator and a water cooling system. The parabolic dish concentrator is used to capture more solar radiation intensity on the TE solar collector. PV modules are mounted on the edge of the parabolic dish and used to drive a pump to cool the TE modules. The effects of water-cooling flow rate and water volume in the storage on various thermal and electric energy and performance parameters are investigated. The detailed information show that the TE solar parabolic dish system can supply clean hot water (40°C) and electricity (5.25 W) at a temperature difference of 164.1°C, and the corresponding conversion efficiency of TE modules is measured to be 3.02%. Therefore, it is anticipated the proposed PV-assisted TE solar parabolic dish system concept will contribute to the standalone solar TE system's production of both electrical and thermal energies simultaneously.

Thermoelectric generator (TEG) that works in medium and high temperature ranges has appeared as a necessity in combating with the waste heat management from various industries. Therefore, design of TEG with thermoelectric materials capable to exhibit high capacity for thermoelectric power generation is of emerging technological interest. It is known that alloys based on Mg2(Si, Sn) and PbTe thermoelectric materials are best suited for the intermediate temperature scale (400–900 K). For constructing a TEG, higher manganese silicides (HMS) are often used for integration with n-type Mg2X (Si, Ge, Sn) alloys. The thermo-mechanical property-mismatch reasons out the option for such a combination in fabrication of a sustainable thermoelectric generator. This makes one focus on evolving a generation system that comprises of both n- and p-type thermo elements prepared from suitable Mg2X (Si, Ge, Sn) alloys. The present research analyses the feasibility of designing a Mg2 (Si, Sn) alloy based thermoelectric generator by modeling approach. It presents a comprehensive take on the effect of thermoelectric leg dimensions and contact resistances on the output voltage, output power and efficiency, with alteration in the operating temperature span. The COMSOL modeling results indicate that the power output reduces considerably with increment in the thermoelectric leg length, while the conversion efficiency enhances. Contrarily, augmenting the cross-sectional area of a thermoelectric leg follows an opposite trend i.e., it increases the power output and decreases the conversion efficiency. The power output and the conversion efficiency values diminish when contact resistances are considered in the modeling study. This study also incorporates an efficient heat exchanger system including contact resistances and conductive and convective heat losses for accurate estimation of power output and efficiency of the optimized TEG module.

[EN] The aim to reduce well to wheel emissions incentives the utilisation of alternative fuels (low to zero carbon content and/or low well to tank emissions) as well as the enhancement of engine efficiency. In parallel, the reduction of engine tailpipe emissions brings new challenges such as the decrease of the exhaust gas temperature. This trend penalises the ability of the exhaust aftertreatment system to eliminate pollutant emissions. In addition, the combustion of alternative fuels and new combustion modes induce changes in the nature and concentration of the exhaust species, which is known to affect the pollutants abatement mechanisms. This investigation provides new understanding on the sensitivity of pollutants abatement in oxidation catalysts to the use of alternative fuels. The studied fuels are conventional diesel, alternative fuels (rapeseed methyl ester and gas to liquid) as well as propane using a dual-fuel combustion strategy. The research combines experimental conversion efficiency from genuine exhaust gases with modelling work useful to explain the reasons for the change in light-off temperature as a function of the fuel. In addition to the CO and NO impact, HC surrogates are proposed distinguishing species of different reactivity for each fuel based on the experimental HC speciation. The results highlight the role of the engine-out emissions on the pollutants conversion efficiency. Their fashion with different fuels contributes to evidence the interest for low engine-out emissions along with low light alkanes content in total HC, as promoted by alternative fuels, to reduce the oxidation light-off temperature., This research has been partially supported by FEDER and the Government of Spain through project TRA2016-79185-R and by Universitat Politecnica de Valencia under a grant with reference number FPI-2018-S2-10 to the Ph.D. student Maria Jose Ruiz

The aim of the present study is the characterization of PVT modules electrical performance in real operating conditions, as well as the investigation of thermal recovery via a cooling circuit integrated with a third generation PV module. The approach combines both theoretical and experimental tools: a MatLab® simulation model provides a reliable theoretical basis, whose validation is performed on experimental evidences from in-field PV module tests. The model represents the module energy balance, under unsteady operating conditions; a full set of measurements allowed to validate the theoretical approach, thus offering the possibility to evaluate the effects of both variable outdoor air temperature and pressure and wind speed. Water-cooled PV modules electrical performance increases by as much as 33%, with respect to the situation in which no cooling is performed and up to a 20% electric efficiency is achieved, with a 2.0 L/min water flow rate on the back. A major drawback is that thermal recovery for cogeneration purposes is not effective, due to a low thermal gradient (10 K maximum) on the water. When a 10 mm thick glass cover was integrated in the PV module along with a frame to reduce wind circulation over exposed surfaces, a 100–500 W thermal recovery on a day basis could be achieved. Furthermore, a 15–30 K increase in water temperature assures about the higher quality of the recoverable heat. The suitability of organic fluids instead of water to reduce the power absorption by the pump, is addressed as the most effective way to increase PVT electric output: the absorption with R236fa and R245fa is a 60% and 75% lower than with water, respectively. The novelty of the present study lies in the dual theoretical and experimental approach, leading to a validated non-steady-state mockup, easily adjustable to extend the analysis to PV modules arrays for residential applications. Furthermore, the use of an infrared camera, typically confined to post-manufacturing quality control, allows here a continuous monitoring of the module thermal field, key to evaluate the temperature effect on the module performances both in steady and unsteady conditions.

This study aims to evaluate the environmental footprint of the integrated France-Italy beef production system (extensive grassland-based suckler cow-calf farms in France with intensive cereal-based fattening farms in northeastern Italy) using a multi-indicator approach, which combines environmental impact categories computed with a cradle-to-farm gate Life Cycle Assessment, and food-related indicators based on the conversion of gross energy and protein of feedstuffs into raw boneless beef. The system boundaries were set from the calves' birth to their sale to the slaughterhouse, including the herd management, on- and off-farm feed production and materials used on the farms. One kilogram of body weight (BW) sold was used as the functional unit. The study involved 73 Charolais batches (i.e., a group of animals homogenous for age, finishing period and fattening farm), kept at 14 Italian farms. Data from 40 farms originating from the Charolais Network database (INRA) were used to characterize the French farm types, which were matched to the fattening batches according to the results of a cluster analysis. The impact categories assessed were as follows (mean +/- SD per kg BW): global warming potential (GWP, 13.0 +/- 0.7 kg CO2-eq, reduced to 9.9 +/- 0.7 kg CO2-eq when considering the carbon sequestration due to French suckler cow-calf system permanent grassland), acidification potential (AP, 193 +/- 13 g SO2-eq), eutrophication potential (EP, 57 +/- 4 g PO4-eq), cumulative energy demand (CED, 36 +/- 5 MJ), and land occupation (LO, 18.7 +/- 0.8 m(2)/year). The on-farm impacts outweighed those of the off-farm activities, except in the case of CED. On average, 41 MJ and 16.7 kg of dietary feed gross energy and protein were required to provide 1 MJ or 1 kg of protein of raw boneless beef, respectively, but nearly 85% and 80%, respectively, were derived from feedstuffs not suitable for human consumption. Emission-related (GWP, AP, EP) and resource utilization categories (CED, LO) were positively correlated. Food-related indicators showed positive correlations with emission-related indicators when the overall feedstuffs of the diet were considered but negative correlations when only the potentially human-edible portions of the beef diets were considered. In conclusion, the integration of the pasture-based France suckler cow-calf system with the cereal-based Italian fattening farms allows for the exploitation of the resources available, increasing the share of non-human-edible feedstuffs while maintaining good livestock productive efficiency. Combining indicators of impact categories with indicators of feed net supply may improve the assessment of the environmental footprint of livestock systems.

This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cell illuminated by an intense light concentration: external load electric power, conversion efficiency, fill factor, external optimal charge load. Due to the high photogeneration of carrier in intense light illumination mode, in addition of magnetic field, we took into account the carrier gradient electric field in the base of the solar cell. Taking into account this electric field and the applied magnetic field in our model led to new analytical expressions of the continuity equation, the photocurrent and the photovoltage.

Binary nanoparticle inks comprising Ag2Se, In2Se3, and Ga2Se3 were fabricated via a wet ball-milling method and were further used to fabricate AgInGaSe2 (AIGS) precursors by sequentially spraying the inks onto a Mo-coated substrate. AIGS precursors were annealed under a Se atmosphere for 1 h at 570 °C. Na2Se thin layers of varying thicknesses (0, 5, 10, and 20 nm) were vacuum-evaporated onto the Mo layer prior to the AIGS precursors being fabricated to investigate the influence on AIGS solar cells. Sodium plays a critical role in improving the material properties and performance of AIGS thin-film solar cells. The grain size of the AIGS films was significantly improved by sodium doping. Secondary ion mass spectroscopy illustrated slight surficial sodium segregation and heavy sodium segregation at the AIGS/Mo interface. Double-graded band profiles were observed in the AIGS films. With the increase in Na2Se thickness, the basic photovoltaic characteristics of the AIGS solar cells were significantly improved. The highest solar cell conversion efficiency of 6.6% (open-circuit voltage: 775.6 mV, short-circuit current: 15.5 mA/cm2, fill factor: 54.9%, area: 0.2 cm2) was obtained when the Na2Se thickness was 20 nm.

A new technology called in vivo glia-to-neuron conversion has emerged in recent years as a promising next generation therapy for neural regeneration and repair. This is achieved through reprogramming endogenous glial cells into neurons in the central nervous system through ectopically expressing neural transcriptional factors in glial cells. Previous studies have been focusing on glial cells in the grey matter such as the cortex and striatum, but whether glial cells in the white matter can be reprogrammed or not is unknown. To address this fundamental question, we express NeuroD1 in the astrocytes of both grey matter (cortex and striatum) and white matter (corpus callosum) to investigate the conversion efficiency, neuronal subtypes, and electrophysiological features of the converted neurons. We discover that NeuroD1 can efficiently reprogram the astrocytes in the grey matter into functional neurons, but the astrocytes in the white matter are much resistant to neuronal reprogramming. The converted neurons from cortical and striatal astrocytes are composed of both glutamatergic and GABAergic neurons, capable of firing action potentials and having spontaneous synaptic activities. In contrast, the few astrocyte-converted neurons in the white matter are rather immature with rare synaptic events. These results provide novel insights into the differential reprogramming capability between the astrocytes in the grey matter versus the white matter, and highlight the impact of regional astrocytes as well as microenvironment on the outcome of glia-to-neuron conversion. Since human brain has large volume of white matter, this study will provide important guidance for future development of in vivo glia-to-neuron conversion technology into potential clinical therapies. Experimental protocols in this study were approved by the Laboratory Animal Ethics Committee of Jinan University (approval No. IACUC-20180321-03) on March 21, 2018.

Secondary phases are common in Cu2ZnSnS4 (CZTS) thin films, which can be fatal to the performance of solar cell devices fabricated from this material. They are difficult to detect by X-Ray diffraction (XRD) because of the weak peak in spectra compared with the CZTS layer. Herein, it was found that in-depth elemental distribution by a secondary ion mass spectroscopy method illustrated uniform film composition in the bulk with slight fluctuation between different grains. X-ray photoelectron spectroscopy (XPS) measurement was conducted after sputtering the layer with different depths. An Auger electron spectrum with Auger parameter were used to check the chemical states of elements and examine the distribution of secondary phases in the CZTS films. Secondary phases of CuS, ZnS and SnS were detected at the surface of the CZTS film within a 50-nm thickness while no secondary phases were discovered in the bulk. The solar cell fabricated with the as-grown CZTS films showed a conversion efficiency of 2.1% (Voc: 514.3 mV, Jsc: 10.4 mA/cm2, FF: 39.3%) with an area of 0.2 cm2 under a 100 mW/cm2 illumination. After a 50-nm sputtering on the CZTS film, the conversion efficiency of the solar cell was improved to 6.2% (Voc: 634.0 mV, Jsc: 17.3 mA/cm2, FF: 56.9%).

We have demonstrated a high-performance low temperature solution processed electron selective contact consisting of 10 at% antimony doped tin oxide (ATO) and the neutral polymer polyethylenimine (PEI). Inverted organic photovoltaics (OPVs) utilizing ATO/PEI as electron selective contact exhibited high power conversion efficiencies for both the reference P3HT: PCBM and the non-fullerene based P3HT- IDTBR active layer OPV material systems. Importantly it is shown that the proposed ATO/PEI carrier selective contact provides light soaking-free inverted OPVs. Furthermore, by increasing the thickness of ATO layer from 40 to 120 nm the power conversion efficiency of the corresponding inverted OPVs remain unaffected a parameter which indicates the potential of the proposed ATO/PEI carrier selective contact for high performance light-soaking-free and reliable roll-to-roll printing solutions processed inverted OPVs., Comment: 20 pages, 4 figures, 2 tables

The objective of the study was to evaluate the growth and production efficiency of forage-grain dual-purpose wheat in two arrangements and four agroforestry systems (Intercrop-I and Intercrop-II), as well as to evaluate crop management for the wheat crops in two planting seasons (Crop Season I-2014 and Crop Season II-2015. The experiment was conducted in a randomized complete block design, factorial scheme 7x2x2, with seven cultivation systems Eucalyptus urophylla x Eucalyptus grandis Intercrop-II and Intercrop-I; Peltophorum dubium Intercrop-II and Intercrop-I; P. rigida Intercrop-I; S. parahyba Intercrop-I; a wheat monoculture with no tree species present; and two harvest management techniques (with and without harvesting of the forage species). Agroforestry systems generated shading for wheat plants, with a higher phyllochron and lower values of leaf area index of those individuals kept under trees with higher crown shading (non-deciduous trees) due to the lower transmissivity of solar radiation. The systems composed with Schizolobium parahyba in Intercrop-I and Parapiptadenia rigida in Intercrop-I provide a minor phyllochron to the wheat, resulting in a higher leaf area index and dry matter yield. Thus, the cultivation of tree species and dual-skilled agricultural crops, such as wheat, provides promising alternatives for the future use of land in tropical countries.

Silicon nitride waveguides have emerged as an excellent platform for photonic applications, including nonlinear optical signal processing, owing to their relatively high Kerr nonlinearity, negligible two photon absorption, and wide transparent bandwidth. In this paper, we propose an effective approach using 3D finite element method to optimize the dispersion characteristics of silicon nitride waveguides for four-wave mixing (FWM) applications. Numerical studies show that a flat and low dispersion profile can be achieved in a silicon nitride waveguide with the optimized dimensions. Near-zero dispersion of 1.16 ps/km/nm and 0.97 ps/km/nm at a wavelength of 1550 nm are obtained for plasma-enhanced chemical vapor deposition (PECVD) and low-pressure chemical vapor deposition (LPCVD) silicon nitride waveguides, respectively. The fabricated micro-ring resonator with the optimized dimensions exhibits near-zero dispersion of −0.04 to −0.1 ps/m/nm over a wavelength range of 130 nm which agrees with the numerical simulation results. FWM results show that near-zero phase mismatch and high conversion efficiencies larger than −12 dB using a low pump power of 0.5 W in a 13-cm long silicon nitride waveguide are achieved.

This study proposes the more effective use of fuel cell (FC) vehicles by providing vehicle-to-grid (V2G) technologies that provide the integration of transportation and electricity networks. The main objective of the current study is to develop an FCV2G system with a high voltage conversion interface for the integration of low voltage FC energy units to utility-grids. To transfer the energy from the fuel cell vehicle (FCV) to the grid/homes with high efficiency, a single-switch high voltage conversion DC-DC converter is proposed, designed and implemented in the FCV2G system. The FCV2G with the proposed converter is analyzed for different operating modes in order to validate the smooth energy transfer with maximum power extraction capability. In the performance section, an FC in the rating of 20 kW (based on Pininfarina Sintesi model) is located in the energy generation unit of FCV2G, and a dynamic load profile is operated for 24 h period. The generated energy from FCV is supplied to consumer loads and electric grids in the rating of 220 Vrms/50 Hz. In the analysis section, during low load consumption, the FCV both meets the energy need of the load, and the excess energy is supplied into the grid. In cases where the homes' energy consumption is higher than the power rating produced by the FCV, the load absorbs the maximum power generated by the FCV and meets the power difference needing from the grid. In the designed model, FCV supplies a 44.06 kW h energy to consumer loads/grids per a day. After the system analysis, economic aspects are supported through energy and profit analysis of the FCV2G system. The results verify that the purchased price from grid-electricity significantly reduces to lower values for daily operation.

A new Selective Solar Absorber, designed to improve the Sun-to-thermal conversion efficiency at mid temperatures in high vacuum flat thermal collectors, is presented. Efficiency has been evaluated by using analytical formulas and a numerical thermal model. Both results have been experimentally validated using a commercial absorber in a custom experimental set-up. The optimization procedure aimed at obtaining Selective Solar Absorber is presented and discussed in the case of a metal dielectric multilayer based on Cr2O3 and Ti. The importance of adopting a real spectral emissivity curve to estimate high thermal efficiency at high temperatures in a selective solar absorber is outlined. Optimized absorber multilayers can be 10% more efficient than the commercial alternative at 250 °C operating temperatures, reaching 400 °C stagnation temperature without Sun concentration confirming that high vacuum flat thermal collectors can give important contribution to the energy transition from fossil fuels to renewable energy for efficient heat production.

[EN] Worldwide emission standards are extending their requirements to cover engine operation under extreme ambient conditions and fill the gap between the type-approval and real driving conditions. The new ambient boundaries affect the engine performance and raw emissions as well as the efficiency of the exhaust aftertreatment systems. This study evaluates the impact of high altitude and low ambient temperature on the light-off temperature and conversion efficiency of an oxidation catalyst. The results are compared in a common range of exhaust mass flow and temperature with the baseline sea-level operation at 20 degrees C. A reduction of CO and HC conversion efficiencies was found at 2500 m and -7 degrees C, with a relevant increase of the light-off temperature for both of the pollutants. The analysis of the experimental data was complemented with the use of a catalyst model to identify the causes leading to the deterioration of the CO and HC light-off. The use of the model allowed for identifying, for the same exhaust mass flow and temperature, the contributions to the variation of conversion efficiency caused by the change in engine-out emissions and tailpipe pressure, which are, in turn, manifested in the variation of the reactants partial pressure and dwell time as governing parameters., This research has been partially supported by FEDER and the Government of Spain through project TRA2016-79185-R. Additionally, the PhD candidate Barbara Diesel has been funded by a grant from the Government of Generalitat Valenciana and FSE (European Union) with reference ACIF/2018/109.

Industrial silicon solar cells like Passivated Emitter and Rear Cells (PERC) typically apply a screen-printed (Ag) front contact with a single print process using a mesh screen. It has been shown that using stencils instead of screens improves the finger profile leading to slightly higher cell conversion efficiencies. However, so far stencil printing required an extra printing step for the busbars since conventional stencils do not support H-pattern designs. In this paper, we evaluate a novel “single print” stencil from ASM AE that allows to print busbars and fingers in a single print step. We apply the novel single print stencil to high-efficiency PERC solar cells and compare it to today's industrial screen printing processes (single print and dual print) as well as to a high performance dual-printed front side grid applying a stencil for the fingers and a screen for the busbars. The printed finger width ranges from 35.8 ± 2.3μm for 30μm stencil opening to 46.7 ± 3.4μm for 40μm screen opening which leads to an 0.5% abs increased metallized area on the front side of the screen printed fingers compared to the stencil printed fingers. The resulting average finger height is 22.3μm for the stencil groups and 11.9μm for the screen printed Ag finger which leads to a difference in the finger line resistance and an additional series resistance contribution for the screen-printed cells of 0.05Ωcm 2 . We achieve almost identical PERC cell efficiencies with the single print stencil and the dual print stencil process obtaining best values up to 21.1% and average values of 21.0%. In contrast, both screen printed groups achieve 0.2% abs lower average conversion efficiencies mostly due to the lower J sc and FF . The advantage of the dual print process compared to single print is shown in the increased V oc by 1 to 2mV due to the used non-firing through Ag busbar paste. With these results we demonstrate that the single print stencil process saves two process steps compared to dual print using a stencil while obtaining the same PERC cell performance with an efficiency gain of 0.2% abs compared to today's industrial screen print processes.

The major technical problems faced by stand-alone fluidized bed gasifiers (FBG) for waste-to gas applications are intrinsically related to the composition and physical properties of waste materials, such as RDF. The high quantity of ash and volatile material in RDF can provide a decrease in thermal output, create high ash clinkering, and increase emission of tars and CO2, thus affecting the operability for clean syngas generation at industrial scale. By contrast, a two-stage process which separates primary gasification and selective tar and ash conversion would be inherently more forgiving and stable. This can be achieved with the use of a separate plasma converter, which has been successfully used in conjunction with conventional thermal treatment units, for the ability to ‘polish’ the producer gas by organic contaminants and collect the inorganic fraction in a molten (and inert) state. This research focused on the performance analysis of a two-stage fluid bed gasification–plasma process to transform solid waste into clean syngas. Thermodynamic assessment using the two-stage equilibrium method was carried out to determine optimum conditions for the gasification of RDF and to understand the limitations and influence of the second stage on the process performance (gas heating value, cold gas efficiency, carbon conversion efficiency), along with other parameters. Comparison with a different thermal refining stage, i.e. thermal cracking (via partial oxidation) was also performed. The analysis is supported by experimental data from a pilot plant.

We have investigated the effect of thermal annealing on the photovoltaic parameters of all-polymer solar cells based on a quinoxaline-thiophene donor polymer (TQ1) and a naphthalene diimide acceptor polymer (N2200). The annealed devices show a doubled power conversion efficiency compared to nonannealed devices, due to the higher short-circuit current (J(sc)) and fill factor (FF), but with a lower open circuit voltage (V-oc). On the basis of the morphology-mobility examination by several scanning force microscopy techniques, and by grazing-incidence wide-angle X-ray scattering, we conclude that better charge transport is achieved by higher order and better interconnected networks of the bulk heterojunction in the annealed active layers. The annealing improves charge transport and extends the conjugation length of the polymers, which do help in charge generation and meanwhile reduce recombination. Photoluminescence, electroluminescence, and light intensity dependence measurements reveal how this morphological change affects charge generation and recombination. As a result, the J(sc) and FF are significantly improved. However, the smaller band gap and the higher HOMO level of TQ1 upon annealing causes a lower V-oc. The blend of an amorphous polymer TQ1, and a semi-crystalline polymer N2200, can thus be modified by thermal annealing to double the power conversion efficiency. Refereed/Peer-reviewed