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The triple-junction solar cell is designed to exploit a wide range of the solar spectrum photons. These triple-layers consisting of GaInP/GaInAs/Ge, it is monolithically stacked, leading to high conversion efficiency. To describe and understand it's operating behaviour, this paper presents a performance analysis of a triple-junction solar cell, based on estimation modelling. A model was developed to determine the performance characteristic of the solar cell. Hence, the J-V curve is characterising the performance of solar cells, which used to optimise and improve the design of the cells. It has been discussed the effects of thermal load related to cell temperature increases on the cell's operating performance parameters. Cell temperature increases from 25 to 125 °C have resulted variances, which causes a significant decrease in efficiency to approximately −17%, open circuit voltage by −15% and fill factor by −4.5%. On the other hand, the current density slightly increased by +5.5%. Finally, ought to consider the thermal management while designing and developing solar CPV technology; therefore, it's significant to improve cell efficiency and to maintain cell integrity from thermal damage.

In the solar cells under the open-circuit condition, the carriers charges emits the external luminescence for balancing the incoming solar radiations. The generation of such external luminescence represents the optical losses in the solar cells. Efficient external luminescence ensures the state of approaching the maximum limit of the SQ (Shockley-Queisser) equation. In this way in solar cell’s need of getting high efficiency is fulfilled if it is also responding as an efficient light-emitting diode. This article focus on achieving a high external luminescence efficiency under the standard solar spectrum with optimum value of fill factor using the optimum values of GaAs solar cell parameters by applying Genetic algorithm. Different geometries based on physics of light absorption are considered for optimum parameter search that can give high external luminiscence efficiency as well as high Value of fill factor.

The transparent envelope structures in existing buildings have caused so much energy consumption. As one kind of the energy-saving technologies and strategies, the solar spectrum selective absorption film (SSAF) is considered suitable for the retrofit of glazing systems. The energy-saving performance of the SSAF in different types of glazing systems under different climate zones in China was investigated via a field study and simulation experiment. The results indicated that SSAF slowed down the rise of indoor air temperature in the daytime and reduced the total energy entering the room. The effect of the SSAF on the single glazing system was more potent than that on the double glazing system. In the hot summer and cold winter zone, moderate zone, hot summer and warm winter zone, the SSAF could reduce the energy consumption of windows. The highest energy-saving rate reached 35.0% for the single glazing system and 28.3% for the double glazing system. However, the SSAF does not have the energy-saving potential in existing buildings that already have low-E double glazing systems.

The article presents the influence of changes in the solar radiation spectrum distribution on the properties of various photovoltaic modules, with particular emphasis on the scattered component. We compared the relative efficiency of the photovoltaic modules based on various semiconductor absorbers during bright and sunny, and cloudy summer days. Additionally, we presented the impact of the module tilt angle on the magnitude of the surface incident scattered component and on the efficiency of the module. The solar spectra for various weather conditions were estimated using specialised computer programmes,such as SolarSpectrum or SMARTS2, and we present here the validation results for the former. The obtained results confirm the published experimental data and the conclusions drawn show the applicability of the tested modules with various absorbers for the specific photovoltaic systems. The theoretical analysis of the a-Si structures, both single-, as well as multi-junction shows better performance of these structures at low-irradiance conditions (in comparison with e.g., c-Si, CIS structures), during days characterised by a spectral distribution common for cloudy days with high air water vapour content. This type of device should show unaltered efficiency both at mid-day, as well as during the morning and late afternoon.

Spectral mismatch correction factor (MM) is determined by average photon energy (APE). APE based on wide solar spectral ranges leads to better description of solar spectral shape. Moreover, error between corrected outdoor short-circuit current (ISC) of PV module and its ISC under standard test conditions is investigated using PV module irradiance sensor (PVMS) and/or MM, where PVMS is a single-crystalline silicon PV module. The error of muti-crystalline silicon (mc-Si) PV module is as low as about 1% regardless of the use of MM attributed to small spectral mismatch between PVMS and mc-Si PV module. On the other hand, the low error of CdTe test PV module is obtained under the use of both PVMS and MM caused by the high spectral mismatch between PVMS and CdTe test PV module. The error is further decreased, when MM is estimated from the APE based on wide ranges of the solar spectrum.

Photocatalysis based on semiconductors has recently been receiving considerable research interest because of its extensive applications in environmental remediation and renewable energy generation. Various semiconductor-based materials that are vital to solar energy utilization have been extensively investigated, among which titanium oxide (TiO2) has attracted considerable attention because of its exceptional physicochemical characteristics. However, the sluggish responsiveness to visible light in the solar spectrum and the inefficient separation of photoinduced electron–hole pairs hamper the practical application of TiO2 materials. To overcome the aforementioned serious drawbacks of TiO2, numerous strategies, such as doping with foreign atoms, particularly nitrogen (N), have been improved in the past few decades. This review aims to provide a comprehensive update and description of the recent developments of N-doped TiO2 materials for visible light-responsive photocatalysis, such as (1) the preparation of N-doped/co-doped TiO2 photocatalysts and (2) mechanistic studies on the reasons for visible light response. Furthermore, the most recent and significant advances in the field of solar energy applications of modified N-doped TiO2 are summarized. The analysis indicated the critical need for further development of these types of materials for the solar-to-energy conversion, particularly for water splitting purposes.

On the basis of density functional theory computations, we demonstrated that two-dimensional (2D) α- and β-Sb2TeSe2 monolayers are promising candidates for constructing high-efficiency heterojunction excitonic solar cells. These two 2D materials possess moderate band gaps (∼1.1 eV), which can be flexibly tuned by applying external strains. They possess high carrier mobility (∼3000 cm2 V-1 s-1) and can absorb sunlight over the whole range of the solar spectrum. Remarkably, the α- and β-Sb2TeSe2 monolayers can form desirable type II heterostructures with HfSe2 and BiOI monolayers, respectively. The power conversion efficiencies of α-Sb2TeSe2/HfSe2 and β-Sb2TeSe2/BiOI heterojunction excitonic solar cells can reach 22.5 and 20.3%, respectively. Since α-Sb2TeSe2 and β-Sb2TeSe2 monolayers have good stability and high synthesis feasibility, they have important applications in photovoltaic solar cell devices.

From an energy-saving perspective, blocking infrared (IR) radiations in the solar spectrum has garnered increased attention, and several heat-shielding nanoparticle-based materials have been employ...

To make full use of the solar spectrum, the performances of Al0.3Ga0.7As/GaAs/Ge and Al0.3Ga0.7As/GaAs/Si/Ge have been simulated using a one-dimensional device simulator called personal computer oe dimension (PC1D). The dependencies of simulated current density–voltage (J–V) and external quantum efficiency (EQE) results on the thicknesses of each sub-cell have been thoroughly analyzed to determine the preferred thickness. Compared to Al0.3Ga0.7As/GaAs/Ge (1.5/5/50 μm), Al0.3Ga0.7As/GaAs/Si (1.5/5/180 μm) has an increase of 0.36 V for open-circuit voltage (Voc) but a slight decrease of 1.55 mA/cm2 for short-circuit current density (Jsc). Subsequently, a monolithic InGaP/GaAs/InGaNAsSb (1.9/1.42/1 eV, 3 J) cell has been mechanically stacked on a Ge cell with four terminals. The Jsc value of 14 mA/cm2 and 6.5 mA/cm2 is calculated for each sub-cell of 3 J cell and bottom Ge cell with integration of EQE measurements. In addition, the TiO2/SiO2/TiO2 (150 nm/1 µm/150 nm, trilayer) interface provides a thermal conductance (2.9 × 106 W K−1) comparable to the direct bond interface. It is believed that the architecture of InGaP/GaAs/InGaNAsSb on the Ge cell with a trilayer interface between is the preferred choice.

Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaic devices that exhibit promise in harvesting the infrared solar spectrum. Solid-state ligand exchange is the method employe...

Semiconductor vacancy engineering has remained a prominent growing field over the past several decades. Modulating electronic structures and surface properties has sparked considerable interest in vacancy-modified photocatalysts. Given vacancy-mediated photocatalysis has only been developed for a relatively short period, significant advance has been made in enhancing light absorption over the full solar spectrum, the efficiency of charge transfer and separation and surface reaction kinetics. This review seeks to highlight the recent impressive progress in vacancy-enhanced photocatalysis. First, we summarize the crafting and characterization of vacancies after defining the classification of vacancies. Second, current developments of semiconductor vacancy engineering in several photocatalysts (i.e., metal oxides, hydroxides, sulfides, Sillen phase related bismuth-containing materials and g-C3N4) are emphasized, focusing on the mechanism of vacancies in regulating the photocatalytic performance. Finally, prospects and challenges regarding vacancy engineering of photocatalytic materials are concluded.

Photoelectrochemical (PEC) water splitting supplies an environmentally friendly, sustainable approach to generating renewable hydrogen fuels. Oxides semiconductors, e.g. TiO2, BiVO4, and Fe2O3, have been widely developed as photoelectrodes to demonstrate the utility in PEC systems. Even though significant effort has been made to increase the PEC efficiency, these materials are still far from practical applications. The main issue of metal oxides is the wide bandgap energy that hinders effective photons harvesting from sunlight. In solar spectrum, over 40% of the energy is located in the near-infrared (NIR) region. Developing sophisticated PEC systems that can be driven by NIR illumination is therefore essential. This review gives a concise overview on PEC systems based on the use of NIR-driven photoelectrodes. Promising candidates as efficient yet practical NIR-responsive photoelectrodes are suggested and discussed. Future outlooks on the advancement of PEC water splitting are also proposed.

It is shown that the use of both sides of solar cells created with the heterojunction technology makes possible an increase in the solar-cell efficiency. The difference in illumination of the front and back sides is associated with transformation of the blue part of the spectrum, which is shown by the example of the spectral dispersion of the quantum efficiency. The average difference between the quantum efficiency for both sides is ~11%. The short-circuit current density with the power of the solar spectrum at sea level from 400 to 1100 nm is 36.3 mA/cm2 for the front side and 32.7 mA/cm2 for the back side. The decrease amounts to 9.7%.

Quantum Dot Sensitized Solar Cells are considered as the potential third generation solar cells due to their suitable optoelectronic properties for photovoltaic response. The possibility of size and composition tunability makes quantum dots as relevant absorber materials to match the wider solar spectrum more efficiently. In conjunction, the possibility of multiple electron-hole pair generations at the cost of single photon i.e. multiple carrier generation is showing potential to overcome the theoretical single junction power conversion efficiency limitations. Quantum dot sensitized solar cells are showing power conversion efficiencies up to 12%, very close to its counterpart dye sensitized solar cells. However, QDSSCs efficiencies are still lagging behind the conventional solid state single junction solar cells. In this review, we will discuss the initial evolution of quantum dot sensitized solar cells with their microscopic working principles. The review will also address development of key building blocks and factors such as various interfaces in QDSSCs, carrier transport and recombination across different interfaces, affecting the power conversion efficiency. Further, fundamental concepts of carrier multiplication and possible theoretical models for multiple exciton generation are discussed towards their impact on the power conversion efficiencies of quantum dot sensitized solar cells.

A solar illumination design with fluorescent coatings to change in crop growth in vertical farms was investigated using simulations based on numerical analysis. The fluorescent reflectors were used as part of the lighting system to improve the irradiation for photosynthesis over the shelves. The reflectors were based on optical glass (BK7) embedded with fluorescent pigments (K2SiF6:Mn4+) and were used in the light distribution system to increase crop production by improving spatial light distribution and altering the solar spectrum. The optimum number of shelves was identified for three different latitudes, considering a fixed size of solar collector. It was estimated that introducing fluorescent reflectors to the system could lead to an increase in crop production exceeding 35%.

Controlling solar spectra via the careful design could realize the optimized utilization of energy. Especially for spectrally selective solar absorbers, achieving the appropriate transition wavelength can boom conversion efficiency for a certain application under the consideration of cost. Here, we experimentally demonstrated a kind of WTa-SiO2 cermet based absorbers with transition wavelength of around 1500 nm, 2000 nm, and 2500 nm, which can meet the versatile applications under the conditions of different operating temperatures and different optical concentrations. All the absorbers possess a promising solar absorptance of above 95% and photothermal efficiency of above 91% at 82 °C with 1 sun, as well as the superior thermal stability at 600 °C due to the formation of tantalum oxide in WTa-SiO2 cermet in the annealing process.

Exploring the underwater solar energy by solar photovoltaic (PV) cells leads to a huge advantage by utilizing the humongous space of water covered by the earth's surface. Even though the amount of solar radiation decreases with the depth of the water, water provides sustainable cooling and cleaning for solar PV cells underwater. There are many challenges and constraints to develop solar PV cells underwater because they are mostly calibrated and amenable to space, dryland, terrestrial, etc., and the solar spectrum is prone to get narrower with the depth of the water. The implementation of solar PV cells underwater is pliable in various commercial and defense applications, such as sensors, water monitoring systems, autonomous vehicles, underwater gliders, etc. In this article, first, a mathematical model has been developed for the solar cell spectrum to incorporate the changes in the solar irradiance with the depth of the water. Furthermore, an experimental setup was designed and implemented to mimic an underwater environment. The performance of the polycrystalline encapsulated solar cell was studied based on the different types of water and the depth of the solar cell underwater. This article manifests that there is a sufficient amount of underwater solar power that can be utilized using PV cells to operate various devices and systems.

CO2 conversion into value-added fuels has been considered as a promising solution to solve environmental problems and energy crises. However, the efficiency of photocatalytic CO2 conversion is low. In addition, infrared light in the solar spectrum is not utilized properly in most traditional photocatalytic reactions. Thus, the search for photocatalysts that exploit the wide solar spectrum to achieve an efficient water-based CO2 conversion performance is still highly challenging. Herein, we construct a WN–WO3 Z-scheme heterostructure to exploit the wide solar spectrum for efficient CO2–H2O conversion into fuels (H2, CO, and CH4) without any sacrificial agents. After 5 h irradiation, the yields of H2, CO, and CH4 are 3.0, 1.4, and 1.9 times higher than that of WN, respectively. The activity improvement is ascribed to the direct Z-scheme mechanism of the WN–WO3 heterostructure under ultraviolet-visible illumination. In addition, the infrared light in sunlight is also utilized by the WN–WO3 heterostructure to generate heat via photo-to-thermal conversion, which further accelerates such a conversion reaction. This work offers a unique perspective for designing transition metal nitride/oxide heterostructures and paves a new way to boost the CO2-to-fuel conversion performance.

Tandem or multijunction solar cells are able to convert sunlight to electricity with greater efficiency than single junction solar cells by splitting the solar spectrum across sub-cells with different bandgaps. With the efficiencies of many common single-junction solar cell materials leveling off near their theoretical efficiency limits, there is renewed interest in applying this approach. However, there is ongoing debate as to the best approach for interconnecting sub-cells in series, or whether it is preferable to operate them independently. In this paper, we provide the first experimental demonstration of a tandem cell architecture with three terminals: one on top of the tandem cell, and two beneath it, in interdigitated back contact configuration. The two cells are interconnected with a transparent conductive adhesive, which is compatible with rough surfaces and exhibits negligible series resistance. Combining GaInP and Si sub-cells in this manner allows us to achieve a GaInP/Si tandem cell with a two-terminal efficiency of 26.4 ± 1.0%. We then show that utilizing all three terminals results in an efficiency boost of 0.9 ± 0.2%, to an efficiency of 27.3 ± 1.0%, and discuss the operation of the cell and its two interacting circuits.

Crystalline silicon (c-Si) solar cells comprise more than 95% of the photovoltaics (PV) market. At wafer-scale, this technology is gradually reaching its practical power conversion efficiency (PCE) limit. Therefore, new performance-driven and scalable alternatives must be developed to further increase the cost-competitiveness of PV. Stacked PV absorbers with decreasing bandgaps in a tandem configuration utilize more efficiently the solar spectrum, and can thereby overcome the single-junction efficiency limit of conventional solar cells. Specifically, the monolithic, two-terminal tandem solar cell implementation promises a simple, yet high-performance technology with high market-relevance. Metal-halide perovskite absorbers have attracted broad interest in their application as the top cell of such a c-Si based tandem solar cell configuration. Practically, the perovskite and c-Si subcells need to be electronically coupled, where the interfacial structure should guarantee efficient charge recombination of majority carriers (collected from each subcell), without inducing minority-carrier recombination. In this article, we review the mechanism underlying efficient recombination junctions, and discuss available materials systems for perovskite-based tandems, as well as additional requirements such as efficient light coupling into the subcells, processing compatibility, scalability of materials and methods, and stability. We extend our discussion beyond c-Si to thin-film bottom cell technologies such as low-bandgap perovskites and chalcogenides. We conclude with an outlook on considerations for industrialization of such interfacial structures.

Solar Doppler velocimetry navigation, which utilizes the Doppler frequency shift between the standard solar and measured solar spectra to invert the velocity of the spacecraft, is an emergi...

When driving on a sunny day, one can sometimes observe a small solar spectrum in the rearview mirror of a vehicle. The formation of this “rainbow” results from the prism-like structure of the rearview mirror. Our investigation of this phenomenon reveals that the resulting spectrum is formed in a manner similar to the way a rainbow is formed by a water droplet. We suggest a demonstration that you can perform so that your students can observe this phenomenon. All that is required is a sunny day, a ring stand, a clamp holder, and rearview mirror.

Low‐intensity high‐temperature (LIHT) solar cells are needed for extended photovoltaic power generation in both the lower atmosphere as well as at the surface of Venus. Double‐junction GaInP/GaAs solar cells that may be able to operate and survive, with suitable encapsulation, for several weeks on the 465°C Venus surface have been developed. These solar cells have been optimized for operation under the Venus solar spectrum, which is different from that of the Earth.

Many research groups have noticed the performance of rapidly developed perovskite/silicon monolithic tandem solar cells (TSCs) under a real situation, but they overlook the short current density mi...

Solar powered steam generation is an emerging area in the field of energy harvest and sustainable technologies. The nano-structured photothermal materials are able to harvest energy from the full solar spectrum and convert it to heat with high efficiency. Moreover, the materials and structures for heat management as well as the mass transportation are also brought to the forefront. Several groups have reported their materials and structures as solutions for high performance devices, a few creatively coupled other physical fields with solar energy to achieve even better results. This paper provides a systematic review on the recent developments in photothermal nanomaterial discovery, material selection, structural design and mass/heat management, as well as their applications in seawater desalination and fresh water production from waste water with free solar energy. It also discusses current technical challenges and likely future developments. This article will help to stimulate novel ideas and new designs for the photothermal materials, towards efficient, low cost practical solar-driven clean water production.

This study discusses the transitional solutions with light-based hydrogen production for a carbon-free or low-carbon future. With a particular focus on the cutting-edge research activities at the Clean Energy Research Laboratory (CERL), some light-based innovative hydrogen production systems are discussed thoroughly. At the CERL, the main motivation is to achieve sustainability via a 3S approach, which is the source, system, and service. Therefore, clean, efficient, affordable, and reliable hydrogen production is seen as the first step towards the transition to a carbon-free future. With this goal in mind, the initial research activities at the CERL cover PV-electrolysis, photocatalysis, and photoelectrochemical cells for sustainable light-based hydrogen production. In the following steps, towards hybridization and system integration, various effective multigeneration systems are designed, built, and tested at the CERL. These multigeneration systems not only enhance the solar spectrum utilization, but also provide additional valuable system products such as electricity, heat, Cl2, NaOH, clean water, and ammonia. Better resource utilization decreases system costs, enhances efficiencies, and certainly lowers the negative environmental footprint. The innovative hydrogen production systems designed at the CERL do not require additional chemicals like most of the photocatalytic systems, and as a result, they have less damage to the limited clean water resources of our planet. Besides, at the CERL, numerous novel systems are developed and tested to produce hydrogen from wastewaters. All of these systems are capable of producing outputs that are widely needed across the globe, which highlights the importance of the research currently taken place at the CERL.

The mismatch between the spectral response of PV cells and the available solar radiation results in conversion losses which increase its temperature and hence decreases its photoelectric efficiency...

This paper is concerned with the numerical modelling of a micromorph silicon tandem solar cell (a-Si:H/µc-Si:H), under series (two-terminal: 2T) and independent (four-terminal: 4T) electrical connection. The study is performed using the simulation software Silvaco TCAD. Both the initial (un-degraded or annealed) state, and the light induced degradation one (well-known Staebler–Wronski effect in a-Si:H) are considered for the studied solar cell, operating under the standard global solar spectrum (AM1.5G). The 2T- and 4T-device optimization is carried out under the effects of the intrinsic (i)-layer thickness of the two sub-cells, and the free carrier mobilities through these layers. By increasing the i-layer thickness of the two sub-cells, the 2T-micromorph tandem cell reveals an optimal conversion efficiency $$\eta$$ of 10% and 7.77% corresponding, respectively, to the initial and degraded states. The 4T-configuration exhibits a relatively better $$\eta$$ of 10.94% at initial state, reduced only to 9.59% at the degraded one. Further improvement of the 2T and 4T-cell output parameters is obtained by increasing the free carrier mobilities, particularly through the top-cell i-layer. By this way, the better $$\eta$$ is also ensured by the 4T-device, which displays an initial state- $$\eta$$ of 12.31%, reduced only to 11.43% at the degraded state. However, the improved efficiencies reached by the 2T-configuration are 11.87% and 10.41% corresponding, respectively, to the initial and degraded states.

Harvesting the full bandwidth of the solar spectrum, especially the near-infrared portion, remains a challenge for solar-to-fuel conversion technology. Plasmonic nanostructures have recently attrac...

Exploring high efficiency, low cost and stable photocatalysts that enable full solar spectrum (UV, visible and near-infrared) utilization for photocatalytic hydrogen generation still faces huge challenge. Herein, a Co2P/CdS Z-scheme photocatalyst without noble metal is rationally fabricated to achieve ultrabroad UV-Vis-NIR-harvesting. Compared to Pt/CdS, CdS and Co2P, the optimized Co2P/CdS exhibits much more outstanding performance with the HER rate of 262.16, 66.98 and 3.93 mmol/g/h under solar, visible (780 nm > λ > 420 nm) and NIR (λ > 780 nm) light, respectively. Particularly, 10% Co2P/CdS displays a prominent AQE value of 2.26% at 700 nm. The Z-scheme transform route can effectively enhance the separation of charge carriers in Co2P/CdS for UV-Vis-driven H2 evolution reaction (HER), as confirmed by PL and photoelectrochemical measurements. More importantly, the Co-S bonds at the interface demonstrated by FTIR, Raman (mapping), XPS and density functional theory (DFT) calculations can act as “bridge” for charge transfer, thereby enhancing the full spectrum-driven H2 evolution. To our best knowledge, this is a rare research on full spectrum-driven photocatalytic HER without noble metal.

Lead bromide-based halide perovskites are of interest for wide-band-gap (>1.75 eV) absorbers for low-cost solar spectrum splitting to boost solar-to-electrical energy conversion efficiency/area by ...

Chalcopyrite CuInTe2 is a direct band gap semiconductor with 1.1 eV energy gap which can be adjusted by doping Ga or Al to match the solar spectrum. The theoretical calculations for CuInTe2 doping ...

Protective layers are always required for Si-based photoelectrodes to achieve long-term stability in solar water splitting, for which TiO2, with excellent chemical stability and the effectiveness o...

The efficiency of solar cell depends on how the different portions of the solar spectrum are converted to electric energy. The efficiency of solar cell can be increased by using multi-solar cells in tandem configuration or tandem solar cell. The device structure and material choice of tandem solar cell can affect their efficiency. Incorporating quantum well in the solar cell structure also affects their efficiency. This work proposed a new solar cell structure with efficiency 47%, which is very promising. Different materials of the cell and the embedded quantum well will help to increase the efficiency of this solar cell. The fabrication of the cell is less complicated than other promising solar cell because of single quantum well structure. Comparison with other published work also shows the improved performance of this cell.

Because the visible and the infrared (IR) regions take up ∼47% and ∼51% of the energy in the solar spectrum (AM 1.5G standard), respectively, utilizing the visible light for plant growth and the IR light for power generation is potentially extremely exciting. IR-absorbing organic semiconductors, with localized IR absorption and visible-light transmittance, would be promising materials for this purpose. Here, flexible transparent organic photovoltaics (TOPVs) based on IR-absorbing organic materials were proposed, which can be a simple, low-cost, and promising way to utilize the IR light for electricity generation, and the penetrated visible light will be utilized for photosynthesis in plants. A power-conversion efficiency of ∼10% with an average visible transmittance of 34% was achieved for TOPV devices. Meanwhile, the side-by-side comparison showed that plants grown under the TOPVs filtered light, and those under normal sunlight yielded very similar results. These outcomes demonstrated the results from TOPV devices beyond simple photovoltaic applications.

ZnO is the dominantly used electron transporting material in high-performance inverted nonfullerene (NF) organic solar cells. Here, we report that nonfullerene acceptors tend to decompose in the presence of ZnO due to its photocatalytic activity under UV illumination. This leads to poor device stability of NF solar cells under solar light illumination. To mitigate this issue, SnO2 is used as an electron-transporting layer that has a wide band gap and is almost irresponsive to the AM1.5 solar spectrum to replace ZnO. NF solar cells with SnO2 display a power conversion efficiency of 14.1% with the PM6:IT-4F active layer and show better device illumination stability than the reference cells with ZnO.

Using broadband solar energy for producing clean water can potentially and effectively solve the water pollution and shortage crisis. With the rapid development of material science and nanotechnology, solar steam generation (SSG), based on photothermal nanomaterials, is expanding by leaps and bounds. This review comprehensively covers the state-of-the-art designs and applications of SSG. In this review, the photothermal effect, water supply, and thermal management are proposed as the three keys for the high-efficiency SSG system. Various kinds of photothermal materials with strong optical absorption covering the broad solar spectrum are classified and discussed with examples. The rational design of the water supply and steam escape system enabling the SSG to proceed smoothly is reviewed. Current efforts to minimize the heat loss by rational thermal management are also presented. As follows, typical applications, such as desalination of seawater, purification of wastewater, photothermal steam sterilization, as well as related applications including light-driven thermoelectric system and photo-heat-catalyst are overviewed. At the end of this review, the remaining challenges, as well as opportunities to be seized, are raised for consideration.

Incorporating passive radiative cooling structures into personal thermal management technologies could effectively defend humans against intensifying global climate change. We show that large-scale woven metafabrics can provide high emissivity (94.5%) in the atmospheric window and high reflectivity (92.4%) in the solar spectrum because of the hierarchical-morphology design of the randomly dispersed scatterers throughout the metafabric. Through scalable industrial textile manufacturing routes, our metafabrics exhibit desirable mechanical strength, waterproofness, and breathability for commercial clothing while maintaining efficient radiative cooling ability. Practical application tests demonstrated that a human body covered by our metafabric could be cooled ~4.8°C lower than one covered by commercial cotton fabric. The cost-effectiveness and high performance of our metafabrics present substantial advantages for intelligent garments, smart textiles, and passive radiative cooling applications.

In this paper, we investigate the suitability of two commonly used rare earth ions viz. Erbium and Ytterbium for building a solar pumped fiber amplifier. Based on the solar spectrum and the absorption cross section for the rare earth ions we find that the Ytterbium is more suitable since it has a larger net absorption over the solar spectrum.

Photocatalysis is one of the potential solutions for meeting global energy and environmental demands. The efficiency of a photocatalyst mostly relies on the intrinsic properties of the semiconductor. However, controlling the excited charge-carrier transportation is crucial in enhancing efficiency. Usually, the drop in photocatalytic efficiencies predominantly results from various recombinative processes of photogenerated electron–hole pairs. Higher bandgap to achieve better oxidation or reduction ability becomes a conundrum to harvest the complete solar spectrum to achieve better rates of reactions. Nevertheless, such drawbacks are not visible in naturally occurring photosynthesis processes. Inspired by that, the artificial Z-scheme photocatalytic mechanism could solve the charge transportation drawbacks by constructing a controlled pathway. Traditional and all-solid-state (ASS) Z-scheme were adopted in the past decades where shuttle redox ion mediators and a solid electron conductor, respectively, were used to couple photocatalytic systems. Despite this innovative approach, back reactions, diffusion-limited charge transfer rates, expensive metal mediators, and shielding effects have limited the process. On the other hand, the recent discovery of a direct Z-scheme mechanism was found to address the disadvantages of traditional and ASS Z-scheme photocatalysts. The direct Z-scheme mechanism involves suppressing the photogenerated charge transfers across the heterojunction by spatially separating them for redox photocatalytic reactions. Despite its potential advantage, confirming a photocatalytic system as a Z-scheme needs appropriate evidence to support which is critical. Therefore this chapter casts light on the drawbacks in photocatalytic processes, a brief history of artificial Z-scheme mechanisms, followed by design strategies and approaches for fabricating efficient photocatalysts. Such comprehensive elucidation can be stimulative as a prospective guide for the commercial implementation of photocatalysis on a large scale.

Summary Infrared PbS colloidal quantum dot (CQD)-based materials receive significant attention because of its unique properties. The PbS CQD ink that originates from ligand exchange of CQDs is highly potential for efficient and stable infrared CQD solar cells (CQDSCs) using low-temperature solution-phase processing. In this review, we present a comprehensive overview of CQD inks for the development of efficient infrared solar cells, which can effectively harvest the photons from the infrared wavelength region of the solar spectrum, including the importance of infrared absorbers for solar cells, the unique properties of CQDs, ligand-exchange determined CQD inks, and related photovoltaic performance of CQDSCs. Finally, we present a brief conclusion, and the possible challenges and opportunities of the CQD inks are discussed in-depth to further develop highly efficient and stable infrared solar cells., Photon Absorption; Colloids; Optical Property; Optical Materials

Cutaneous photobiology studies have focused primarily on the ultraviolet portion of the solar spectrum. Visible light (VL), which comprises 50% of the electromagnetic radiation that reaches the Earth's surface and, as discussed in Part I of this CME, has cutaneous biologic effects, such as pigment darkening and erythema. Photoprotection against VL includes avoiding the sun, seeking shade, and using photoprotective clothing. The organic and inorganic ultraviolet filters used in sunscreens do not protect against VL, only tinted sunscreens do. In the United States, these filters are regulated by the Food and Drug Administration as an over-the-counter drug and are subject to more stringent regulations than in Europe, Asia, and Australia. There are no established guidelines regarding VL photoprotection. Alternative measures to confer VL photoprotection are being explored. These novel methods include topical, oral, and subcutaneous agents. Further development should focus on better protection in the ultraviolet A1 (340-400 nm) and VL ranges while enhancing the cosmesis of the final products.

With the growing development of the Internet of Things, organic photovoltaic (OPV) cells are highly desirable for indoor applications because of the unique features of light weight, flexibility, and coloration. Emission spectra of the commonly used indoor light sources are much narrower with lower light intensity as compared to the standard solar spectrum. High tunability in optical absorption, insensitivity to series resistance and the active layer thickness, and mild operating conditions make indoor OPV cells promising as a practically relevant technology. Currently, the OPV module has obtained a power conversion efficiency of over 20%, with excellent stability under indoor conditions. However, at the present stage, the device physics investigations and material design strategies developed in an OPV cell for indoor applications lag behind those for outdoor applications. In particular, the emerging characterizations in photovoltaic measurements have severely affected the reliability of reports. This Spotlight on Applications highlights these opportunities and challenges of OPV cells for indoor applications and reviews the recent progress in indoor OPV cells. In addition, we summarize some studies related to accurate measurement and provide some recommendations.

Photo-catalysis is a research field with broad applications in terms of potential technological applications related to energy production and managing, environmental protection, and chemical synthesis fields. A global goal, common to all of these fields, is to generate photo-catalytic materials able to use a renewable energy source such as the sun. As most active photocatalysts such as titanium oxides are essentially UV absorbers, they need to be upgraded in order to achieve the fruitful use of the whole solar spectrum, from UV to infrared wavelengths. A lot of different strategies have been pursued to reach this goal. Here, we selected representative examples of the most successful ones. We mainly highlighted doping and composite systems as those with higher potential in this quest. For each of these two approaches, we highlight the different possibilities explored in the literature. For doping of the main photocatalysts, we consider the use of metal and non-metals oriented to modify the band gap energy as well as to create specific localized electronic states. We also described selected cases of using up-conversion doping cations. For composite systems, we described the use of binary and ternary systems. In addition to a main photo-catalyst, these systems contain low band gap, up-conversion or plasmonic semiconductors, plasmonic and non-plasmonic metals and polymers.

We report on a solar cell using bottom-up synthesized InP nanowire arrays with an independently verified power conversion efficiency of 16.7% under AM1.5G solar spectrum. This value, which is the highest reported efficiency for bottom-up synthesized nanowire solar cells, was reached after a stabilized improvement of the device during characterization, by improving both back and front contacts of the more than five million nanowires that are connected in parallel in our solar cell.

Cadmium telluride and silicon are among the widely used absorber materials in photovoltaic industry. A tandem solar cell of these two can absorb significant portion of solar spectrum to yield high efficiency due to the added voltage of the two solar cells. On basis of low-cost production, a CdTe/Si cell has the potential to produce low-cost and high efficiency tandem PV. The CdTe top cell in a substrate configuration is essential to achieve a tandem between CdTe and Si. A functional CdS/CdTe solar cell in the substrate configuration was fabricated on a Si wafer. Current-Voltage measurements show a diode-like curve with lower J-V parameters compared to standard CdS/CdTe cells. SCAPS simulations were performed to identify possible reasons for poor performance and help improve the device performance.

International audience; This paper presents an optimization and simulation of optical and electrical properties of GaAsPN/GaAs tandem Dual-Junction solar cells such as current density-voltage (J-V), external quantum efficiency (EQE), with an AM1.5 solar spectrum. We comparing the simulated performance of various N fractions and we will show that the use of N=0.01 improve the performances of external quantum efficiency (EQE) and current-voltage characteristics. Our results have been shown that an optimal efficiency of about 26.19% was obtained with P composition x=0.37 and N fractions y=0.01. In addition, a doping of 2.1018 cm-3 of the GaAs0.62P0.37N0.1 base top cell boosts the efficiency from 25.73% to 26.19%.

Searching for cost-effective photothermal material that can harvest the full solar spectrum is critically important for solar-driven water evaporation. Metal oxides are cheap materials but cannot cover the full solar spectrum. Here we prepared a hydrogenated metal oxide (H

Strained InGaAs (In = 8%) quantum wells (QW) were inserted into the intrinsic region of n-i-p InGaP/GaAs heterojunction solar cells, with thin (1 nm to 4nm) GaAs barriers separating the QWs. This design exhibited improved carrier collection from the QWs as compared to thicker barrier designs, as well as almost no degradation in Voc from control devices without QWs. Champion devices incorporating three layers of strained InGaAs QWs exhibited conversion efficiencies of >26%, exceeding that of the control, with corresponding short circuit current of 30.22 mA/cm2 and open circuit voltage of 1.03V under 1-sun AM1.5G solar spectrum.

Although solar energy is the fastest growing power technology, terrestrial solar panels typically fall behind their performance ratings established under standardised test-conditions. In particular, the angular-tilt of a panel can greatly affect its overall performance. Many studies thus aim to find the optimum tilt that maximises the annual insolation level. However, no widespread consensus has so far been found, partly because of different model assumptions applied. Here, a technique is proposed to use actual, historical solar spectra for the rigorous assessment of a panel’s tilt at a specific site. By combining multiple, free-accessible satellite-retrieved data products, the total all-sky insolation levels are tracked with a minutely changing global (hemispherical) solar spectrum over many years. While time-resolved annual insolation profiles can considerably vary among each other, the solar angle-resolved profile turns out to be robust to climatic conditions and is even site-independent for latitude-tilted panels. These findings can potentially unlock innovative yield optimisation methods.