Search

Organic phototransistors, renowned for their exceptional biocompatibility, hold promise in phototherapy for tracking the efficacy of photosensitive drugs within treatment areas. Nevertheless, it has been found that organic semiconductors are less effective in detecting ultraviolet (UV) light because of their narrow bandgap. Here, we show that UV photodetection in phototransistors using donor-acceptor (D-A) polymer semiconductors can be significantly enhanced by incorporating PCBM nanocrystals. This integration results in a band mismatch between the nanocrystals and the D-A polymer at the interface. These nanocrystals also demonstrate a notable capability of modulating threshold voltage under UV light. The devices incorporating nanocrystals exhibit a photoresponsivity of 0.16 A/W, surpassing the photoresponsivity of the devices without nanocrystals by 50%. The specific detection rate of devices with nanocrystals is around 2.00 × 1010 Jones, which is twice as high as that of devices without nanocrystals. The presented findings offer a potential avenue to improve the efficiency of polymer phototransistors for UV detection. [ABSTRACT FROM AUTHOR]

Polymer-based composites with excellent dielectric properties are essential for advanced energy storage applications. In this work, the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as a filler was incorporated into the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) composite to improve its dielectric performance. P(VDF-HFP) composite films with varying PCBM concentrations were prepared via solution casting and their dielectric, energy storage, and charge–discharge properties were characterized. It was found that the doped PCBM could introduce new charge traps with an energy level of 1.25 eV that modulate charge transport and energy storage characteristics of the polymer matrix. The dielectric constant of the composites was enhanced to the maximum of 10.87 as 0.2 vol% PCBM was added, while the breakdown strength reached 455 MV/m, achieving an energy density of 7.38 J/cm3, which is 33% higher than the pristine P(VDF-HFP) film. Furthermore, the charge–discharge efficiency of the composites was enhanced 66% under the electric field of 300 MV/m. These results demonstrate that PCBM significantly improves the dielectric and energy storage properties of P(VDF-HFP) composites, providing a promising approach for the development of high-performance dielectric materials in flexible energy storage devices. [ABSTRACT FROM AUTHOR]

We analyzed the interaction of three materials, reduced graphene oxide (RGO), [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and poly(3-hexylthiphene) (P3HT), as well as the dependence of its photophysical properties within the temperature range of 90 to 300 K. The nanocomposite of the films was analyzed by optical absorption ultraviolet–visible (UV-Vis) and photoluminescence (PL) and emission ellipsometry (EE) as a function of sample temperature. The surface morphology was studied by atomic force microscopy (AFM). We noted that onset levels (Eonset) of the nanocomposite of P3HT and RGO are smaller than the others. The PL spectra showed the presence of anomalies in the emission intensities in the nanocomposite of P3HT and PCBM. It was also possible to determine the electron–phonon coupling by calculating the Huang–Rhys parameters and the temperature dependence of samples. Through EE, it was possible to analyze the degree of polarization and the anisotropy. We observed a high degree of polarized emission of the P3HT films, which varies subtly according to the temperature. For nanocomposites with RGO, the polarization degree in the emission decreases, and the roughness on the surface increases. As a result, the RGO improves the energy transfer between adjacent polymer chains at the cost of greater surface roughness. Then, the greater energy transfer may favor applications of this type of nanocomposite in organic photovoltaic cells (OPVCs) with enhancement in energy conversion efficiency. [ABSTRACT FROM AUTHOR]

Organic electronics have great potential due to their flexible structure, high performance, and their ability to build effective and low-cost photodetectors. We investigated the parameters of the P3HT and PCBM layers for device performance and optimization. SCAPS-1D simulations were employed to optimize the thicknesses of the P3HT and PCBM layers, investigate the effects of shallow doping in the P3HT layer, and assess the influence of the back contact electrode's work function on device performance. Furthermore, this study explored the impact of interface defect layer density on the characteristics of the device. Through systematic analyses, the optimal parameters for enhancing device responsivity were identified. The findings indicate that a P3HT layer thickness of 1200 nm, a PCBM layer thickness of 20 nm, and a back contact electrode with a work function of 4.9 eV achieve the highest responsivity. Notably, at a bias of −0.5 V, the responsivity exceeds 0.4 A/W within the wavelength range of 450 nm to 630 nm. These optimized parameters underscore the significant potential of the developed device as an organic photodetector, particularly for visible light detection. [ABSTRACT FROM AUTHOR]

To unlock the full potential of PSCs, machine learning (ML) was implemented in this research to predict the optimal combination of mesoporous‐titanium dioxide (mp‐TiO2) and weight percentage (wt%) of phenyl‐C61‐butyric acid methyl ester (PCBM), along with the current density (Jsc), open‐circuit voltage (Voc), fill factor (ff), and energy conversion efficiency (ECE). Then, the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM‐PSCs with nanopatterned TiO2 layer. Subsequently, the PCBM‐PSCs with nanopatterned TiO2 layers were fabricated and characterized to further understand the effects of nanopatterning depth and wt% of PCBM on PSCs. Experimentally, the highest ECE of 17.338% is achieved at 127 nm nanopatterning depth and 0.10 wt% of PCBM, where the Jsc, Voc, and ff are 22.877 mA cm−2, 0.963 V, and 0.787, respectively. The measured Jsc, Voc, ff, and ECE values show consistencies with the ML prediction. Hence, these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs but also highlighted that nanopatterning depth has a significant impact on Jsc, and the incorporation of PCBM on perovskite layer influenced the Voc and ff, which further boosted the performance of PSCs. [ABSTRACT FROM AUTHOR]

An experimental investigation has been undertaken to explore a variety of properties of organic perovskite solar cells (OPSCs) that are distinct in their photovoltaic response. In this study, OPSCs were constructed using zinc oxide, ZnO and [6,6]-phenylC 6 1 -acid methyl ester, PCBM, as electron transfer materials (ETM), poly(3-hexylthiophene), P3HT, as hole transport material (HTM), and CH3NH3PbIX2 as a photosensitizer, where X is either Cl or I. The structural and optical characteristics of the ETM and HTM layers and the perovskite materials of OPSCs were investigated. The I – V and P – V curves of each solar cell prepared in OPSCs were measured using an integrated cell tester. This comprises a photovoltaic I – V measurement system and a solar simulation system. As a result of these results, the OPSC's performance is evaluated. The calculations in this work suggest that the highest power conversion efficiency (PCE = 6.31%) was achieved in photovoltaic devices using CH3NH3PbI3 as the effective absorber layer and ZnO with PCBM as the ETM layer. At a light intensity of 100 mW/cm2, each OPSC cell was performed. Under the same conditions, the I – V curves were evaluated for each OPSC device. By improving the selection of organic and inorganic active materials in the ETM layer, OPSC performance may be improved. [ABSTRACT FROM AUTHOR]

In this study we develop a strategy to insulate 6,6 ‐Phenyl C61 butyric acid methyl ester (PCBM) on the basal plane of transition metal dichalcogenides (TMDs). Concretely single layers of MoS2, MoSe2, MoTe2, WS2, WSe2 and WTe2 and ultrathin MoO2 and WO2 were grown via chemical vapor deposition (CVD). Then, the thiol group of a PCBM modified with cysteine reacts with the chalcogen vacancies on the basal plane of TMDs, yielding PCBM‐MoS2, PCBM‐MoSe2, PCBM‐WS2, PCBM‐WSe2, PCBM‐WTe2, PCBM‐MoO2 and PCBM‐WO2. Afterwards, all the hybrid materials were characterized using several techniques, including XPS, Raman spectroscopy, TEM, AFM, and cyclic voltammetry. Furthermore, PCBM causes a unique optical and electrical impact in every TMDs. For MoS2 devices, the conductivity and photoluminescence (PL) emission achieve a remarkable enhancement of 1700 % and 200 % in PCBM‐MoS2 hybrids. Similarly, PCBM‐MoTe2 hybrids exhibit a 2‐fold enhancement in PL emission at 1.1 eV. On the other hand, PCBM‐MoSe2, PCBM‐WSe2 and PCBM‐WS2 hybrids exhibited a new interlayer exciton at 1.29–1.44, 1.7 and 1.37‐154 eV along with an enhancement of the photo‐response by 2400, 3200 and 600 %, respectively. Additionally, PCBM‐WTe2 and PCBM‐WO2 showed a modest photo‐response, in sharp contrast with pristine WTe2 or WO2 which archive pure metallic character. [ABSTRACT FROM AUTHOR]

Perovskite-based metal oxide phototransistors have emerged as promising photodetection devices owing to the superior optoelectronic properties of perovskite materials and the high carrier mobility of metal oxides. However, high dark current has been one major problem for this type of device. Here, we studied the dark current behaviors of phototransistors fabricated based on the Indium Gallium Zinc Oxide (IGZO) channel and different perovskite materials. We found that depositing organic–inorganic hybrid perovskites materials (MAPbI3/FAPbI3/FA0.2MA0.8PbI3) on top of IGZO transistor can increase dark current from ~10−6 mA to 1~10 mA. By contrast, we observed depositing an inorganic perovskite material, CsPbI3, incorporated with PCBM additive can suppress the dark current down to ~10−6 mA. Our study of ion migration reveals that ion migration is pronounced in organic–inorganic perovskite films but is suppressed in CsPbI3, particularly in CsPbI3 mixed with PCBM additive. This study shows that ion migration suppression by the exclusion of organic halide and the incorporation of PCBM additive can benefit low dark current in perovskite phototransistors. [ABSTRACT FROM AUTHOR]

Inorganic–Organic hybridization provides an alternative route for resolving the limitations associated with crystalline silicon (c-Si) such as high temperature processing, complex fabrication techniques by taking integrated advantages of both the materials. Therefore, hybrid heterojunction solar cell (HSCs) becomes promising candidates in easy and efficient fabrication of photovoltaic (PV) devices. Thus, to fabricate and comprehend the working principle of a practical, economical, and viable device with better PV performance, numerical modelling and simulation plays a very crucial role in cutting down the cost of fabrication, minimising the experimental time scale and producing great integration capabilities. Hence, the performance of phenyl-C61-butyric acid methyl ester (PCBM) with p-Si was analysed by exploring the effect of various controllable material parameters such as: thickness, acceptor density, donor density, defect density, back metal contact, temperature, light intensity and resistances using Solar Cell Capacitance Simulator in one Dimension (SCAPS-1D) tool. It is found that the solar cell design, 'Ag/PCBM/p-Si/Au' can achieve device power conversion efficiency as high as 27.67% under the optimized set of parameters. These parameters are: thickness of p-Si as 200 µm, acceptor density and defect density of p-Si as 1019 cm−3 and 1014 cm−3 respectively, thickness of PCBM as 5 nm and its donor density as 1020 cm−3; temperature of the solar cell as 300 K for the minimum (0 Ωcm2) and maximum (1.0 × 106 Ωcm2) values of series and shunt resistance respectively with Au (5.1 eV) as back metal contact under the illumination intensity of 100 mW/cm2. Results of the study provides exhaustive theoretical basis for conducting experimental study and providing constructive research avenues for PV industry in fabricating simple, efficient and high performing solar cells in near future. [ABSTRACT FROM AUTHOR]

Organic phototransistors, renowned for their exceptional biocompatibility, hold promise in phototherapy for tracking the efficacy of photosensitive drugs within treatment areas. Nevertheless, it has been found that organic semiconductors are less effective in detecting ultraviolet (UV) light because of their narrow bandgap. Here, we show that UV photodetection in phototransistors using donor-acceptor (D-A) polymer semiconductors can be significantly enhanced by incorporating PCBM nanocrystals. This integration results in a band mismatch between the nanocrystals and the D-A polymer at the interface. These nanocrystals also demonstrate a notable capability of modulating threshold voltage under UV light. The devices incorporating nanocrystals exhibit a photoresponsivity of 0.16 A/W, surpassing the photoresponsivity of the devices without nanocrystals by 50%. The specific detection rate of devices with nanocrystals is around 2.00 × 1010 Jones, which is twice as high as that of devices without nanocrystals. The presented findings offer a potential avenue to improve the efficiency of polymer phototransistors for UV detection.

Polymer-based composites with excellent dielectric properties are essential for advanced energy storage applications. In this work, the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as a filler was incorporated into the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) composite to improve its dielectric performance. P(VDF-HFP) composite films with varying PCBM concentrations were prepared via solution casting and their dielectric, energy storage, and charge–discharge properties were characterized. It was found that the doped PCBM could introduce new charge traps with an energy level of 1.25 eV that modulate charge transport and energy storage characteristics of the polymer matrix. The dielectric constant of the composites was enhanced to the maximum of 10.87 as 0.2 vol% PCBM was added, while the breakdown strength reached 455 MV/m, achieving an energy density of 7.38 J/cm3, which is 33% higher than the pristine P(VDF-HFP) film. Furthermore, the charge–discharge efficiency of the composites was enhanced 66% under the electric field of 300 MV/m. These results demonstrate that PCBM significantly improves the dielectric and energy storage properties of P(VDF-HFP) composites, providing a promising approach for the development of high-performance dielectric materials in flexible energy storage devices.

We analyzed the interaction of three materials, reduced graphene oxide (RGO), [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and poly(3-hexylthiphene) (P3HT), as well as the dependence of its photophysical properties within the temperature range of 90 to 300 K. The nanocomposite of the films was analyzed by optical absorption ultraviolet–visible (UV-Vis) and photoluminescence (PL) and emission ellipsometry (EE) as a function of sample temperature. The surface morphology was studied by atomic force microscopy (AFM). We noted that onset levels (Eonset) of the nanocomposite of P3HT and RGO are smaller than the others. The PL spectra showed the presence of anomalies in the emission intensities in the nanocomposite of P3HT and PCBM. It was also possible to determine the electron–phonon coupling by calculating the Huang–Rhys parameters and the temperature dependence of samples. Through EE, it was possible to analyze the degree of polarization and the anisotropy. We observed a high degree of polarized emission of the P3HT films, which varies subtly according to the temperature. For nanocomposites with RGO, the polarization degree in the emission decreases, and the roughness on the surface increases. As a result, the RGO improves the energy transfer between adjacent polymer chains at the cost of greater surface roughness. Then, the greater energy transfer may favor applications of this type of nanocomposite in organic photovoltaic cells (OPVCs) with enhancement in energy conversion efficiency.

Replacing the traditional CdS buffer layer with more environmentally friendly materials is an urgent issue for environment‐friendly CZTSSe solar cells. Herein, a nontoxic, flexible, and conductive organic molecular semiconductor PCBM to replace CdS is used and a Cd‐free CZTSSe solar cell is obtained. By introducing mild spin‐coated ZnO window layers, the damage of PCBM in conventional sputtering ZnO process is effectively avoided, and a higher efficiency than previously reported organic semiconductor buffer layer systems and comparable to CdS buffer layer devices are achieved. The flexible PCBM covers the surface of the CZTSSe absorber layer densely and forms a flatter film surface, which is beneficial for the following ZnO deposition. The CZTSSe/PCBM interface exhibits a typical "spike‐like" energy band alignment with a conduction band offset value of only 0.1 eV. Compared with CZTSSe/CdS interface, the CZTSSe/PCBM heterojunction possesses larger interfacial recombination resistance and a longer carrier lifetime. The ideal coating ability, suitable energy band alignment, as well as the better interface carriers transfer behavior suggest that the organic molecular semiconductors can be used instead of the CdS buffer layer to pave the way for truly environment‐friendly kesterite photovoltaic devices. [ABSTRACT FROM AUTHOR]

Organic photovoltaic cells are electronic devices that convert sunlight into electricity. To this end, the number of studies on organic photovoltaic cells (OVCs) is growing, and this trend is expected to continue. Computational studies are still needed to verify and prove the capability of CVOs, specifically the nanometer molecule PCBM, based on successful experimental results. In this paper, we present a theoretical and computational investigation of PCBM and PC71BM derivatives using the DFT method. On this basis, we employ independent and time-dependent density theories. HOMO, LUMO and GAPH-L energies, ionization potentials and electronic affinity are determined and found to be in agreement with experiments. Using DFT theory based on B3LYP and M062X methods with bases 6-31G (d,p) and 6-311G (d), calculations show that the most efficient acceptors are presented in the group of PC71BM derivatives and are in substantial agreement with experiments. The geometries of the structures are optimized by Gaussian 09. [ABSTRACT FROM AUTHOR]

Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C71 butyric acid methyl ester (PCBM) polymer solar cell is studied by using GPVDM simulations and experiments. The research focuses on the effects of active layer thickness on solar cell structures as bulk heterojunction (BHJ) (ITO/P3HT:PCBM/Al) as compared to a bilayer structure (ITO/P3HT/PCBM/Al). The optimal active layer thickness of 200 nm is obtained in the simulation for BHJ solar structure. The results also indicate that bulk heterojunctions exhibit slightly higher efficiency than bilayer solar cell with the same thickness, possibly due to a better and worthier total surface region for charge separation and reduced recombination between the electrons and holes. BHJ solar cell is fabricated in the experiment by using spin coating. The results show that higher spin speeds result in a thinner active layer, and the device coated at 2500 rpm had the highest power conversion efficiency of 0.91 % because of a higher Isc and fill factor, despite a low absorption. The results suggest that bulk resistance, and morphology of the active layer play important roles in the carrier transport in the P3HT:PCBM solar cell.

Organic semiconductor materials are widely used in X‐ray detection. It has advantages such as flexibility, low cost, and high sensitivity. In this paper, we present an X‐ray detector utilizing a heterojunction structure composed of TIPS‐pentacene and PCBM. This structure incorporates SEBS technology while increasing the charge carrier mobility, thus increasing the flexibility of the device and reducing the dark current. Finally, the device provides ideas for the development of low‐cost, high‐performance direct X‐ray detectors. [ABSTRACT FROM AUTHOR]

Organic electronics have great potential due to their flexible structure, high performance, and their ability to build effective and low-cost photodetectors. We investigated the parameters of the P3HT and PCBM layers for device performance and optimization. SCAPS-1D simulations were employed to optimize the thicknesses of the P3HT and PCBM layers, investigate the effects of shallow doping in the P3HT layer, and assess the influence of the back contact electrode’s work function on device performance. Furthermore, this study explored the impact of interface defect layer density on the characteristics of the device. Through systematic analyses, the optimal parameters for enhancing device responsivity were identified. The findings indicate that a P3HT layer thickness of 1200 nm, a PCBM layer thickness of 20 nm, and a back contact electrode with a work function of 4.9 eV achieve the highest responsivity. Notably, at a bias of −0.5 V, the responsivity exceeds 0.4 A/W within the wavelength range of 450 nm to 630 nm. These optimized parameters underscore the significant potential of the developed device as an organic photodetector, particularly for visible light detection.

Perovskite-based metal oxide phototransistors have emerged as promising photodetection devices owing to the superior optoelectronic properties of perovskite materials and the high carrier mobility of metal oxides. However, high dark current has been one major problem for this type of device. Here, we studied the dark current behaviors of phototransistors fabricated based on the Indium Gallium Zinc Oxide (IGZO) channel and different perovskite materials. We found that depositing organic–inorganic hybrid perovskites materials (MAPbI3/FAPbI3/FA0.2MA0.8PbI3) on top of IGZO transistor can increase dark current from ~10−6 mA to 1~10 mA. By contrast, we observed depositing an inorganic perovskite material, CsPbI3, incorporated with PCBM additive can suppress the dark current down to ~10−6 mA. Our study of ion migration reveals that ion migration is pronounced in organic–inorganic perovskite films but is suppressed in CsPbI3, particularly in CsPbI3 mixed with PCBM additive. This study shows that ion migration suppression by the exclusion of organic halide and the incorporation of PCBM additive can benefit low dark current in perovskite phototransistors.

Wide‐bandgap perovskite solar cells (PSCs) are a promising technology with a series of potential applications, including tandem photovoltaics, solar‐driven electrochemical energetic devices, and outfit morphing power supply for underwater equipment. However, the energy‐level difference between the charge transport layer and perovskite may result in inefficient interfacial charge extraction, leading to the series carrier accumulation at the interface that impairs the photovoltaic performance. Herein, [6,6]‐phenyl C61 butyric acid methyl ester is introduced between SnO2 and FAPbBr3 to alleviate the energy‐level mismatch. Significant photoluminescence quenches and decreased series resistance both verify the promoted interfacial charge extraction efficiency. Besides, the film on the flattened nonwetting electronic transport layers film has better quality, thus reducing defect density and nonradiative recombination. As a result, a 20% power conversion efficiency (PCE) improvement, from 7.02% to 8.55%, is achieved under AM1.5G illumination. More importantly, for the first time, this work demonstrates a highly efficient PSC with a PCE over 43% under the 532 nm laser condition, providing a promising wireless fast charging way with high‐power laser irradiation in deep ocean. [ABSTRACT FROM AUTHOR]

The operational stability of p–i–n perovskite solar cells (PSCs) is dramatically subjected to the quality of the perovskite light harvester and the interface layer atop the perovskite. Herein, a dual crosslinked functional layer strategy of using the versatile polydimethylsiloxane as an additive both in the perovskite layer and in phenyl‐C61‐butyric acid methyl ester interface layer, to improve the device tolerance against light, thermal, humidity, and bending stress, is reported. As a result, a promising power conversion efficiency of 21.6% (stabilized at 21.3%) for nickel oxide‐based p–i–n PSCs is achieved. In addition, the unencapsulated devices maintain 97% of their initial efficiencies after continuous operation under 1 sun equivalent illumination at 60 °C with maximum power point tracking for 1000 h and 80% of their initial efficiencies exposed in ambient air for 500 h. The application of the aforementioned strategy in the flexible device also improves the bending mechanical stability, of which the corresponding flexible devices maintain 85% of their initial efficiencies after 1000 cycles at a radius of 8 mm. [ABSTRACT FROM AUTHOR]

The optimization of semi-transparent organic solar cells involves balancing average visible transparency (AVT) and power conversion efficiency (PCE). We propose enhancing ST-OSC performance by replacing the conventional opaque Ag electrode with a MoO 3 /Ag/MoO 3 as a dielectric/metal/dielectric (DMD) layer structure, explored theoretically and experimentally. A prototype ST-OSC configuration, comprising ITO/ZnO/P3HT: PCBM/MoO3/Ag/MoO3, was fabricated with varying thicknesses of the MoO 3 /Ag/MoO 3 layer, determined through theoretical calculations utilizing MATLAB software. This study investigates the impact of metal layer thickness on two active layer densities (10 and 18 mg/mL) and evaluates AVT, color rendering index, Correlated Color Temperature, and CIELAB color coordinates (a*, b*). Both theoretical calculations and experimental results confirm that the optimized configuration of the DMD structure with specific layer thicknesses for each component (MoO 3 = 10nm/Ag = 6nm/MoO 3 = 30 nm) achieves an AVT of over 59.60 %. This high level of transparency makes this configuration suitable for applications requiring both high transparency and efficient light transmission. The optimized device delivered high-quality light transmission, approaching white perception to the human eye. This combined approach validates empirical results and provides a deeper understanding of transparent OSC mechanisms. [Display omitted] • MoO 3 /Ag/MoO 3 is an effective transparent top electrode in semi-transparent solar cells. • Optimizing with a 6 nm Ag layer maximizes AVT to 65.5%. • All Ag thickness variations achieve AVT > 50%, suitable for windows. • Study evaluates color parameters for building integration. • Experimental and theoretical results show good agreement. [ABSTRACT FROM AUTHOR]

Poly(3‐hexylthiophene), or P3HT, is a semicrystalline polymer with charge conduction anisotropy with respect to its different axes, which calls for gaining better control of texture for targeted device applications. A blend system of P3HT and [6,6]‐phenyl C61‐butyric acid methyl ester (PCBM) is studied for understanding the role of PCBM in texture control of P3HT crystallites. 2D grazing incidence diffraction (2D‐GIXD) combined with high resolution grazing incidence X‐ray diffraction (1D‐GIXD) is performed on thin films of pristine P3HT and blend (P3HT/PCBM) thin films prepared by spin coating. Thermal annealing at 110 °C is used for relaxing the films. The lamellar P3HT crystallites preferably orient along the surface plane with lamellar stacking in a vertical direction and have a distribution of orientation with a limiting angle of 44°. In the pristine P3HT system, the rotations of crystallites are confirmed by the retreat of the limiting angle. The observed intensity cross‐over for precursor and annealed samples is again the signature of the rotations of crystallites. For the blend system, the intensity cross‐over is absent and there is no sign of retreat of the limiting angle, which explicitly confirms the blocking of rotation lamellar crystallites. This study provides, for the first time, the clear evidence with unambiguous analysis of blocking of rotation of crystallites due to presence of PCBM, which is explained with an analogy of the "ball‐and‐stick" mechanism. Atomic force microscopy (AFM) studies of surface morphology correlates with the above findings. [ABSTRACT FROM AUTHOR]

This contribution demonstrates the effects of mole ratio, concentration of perovskite components and fullerene derivatives used as electron transport layer (ETL) on the stability and performances of inverted perovskite solar cells (PSCs). C60, C70, PC61BM and PC71BM are selected as ETL materials. Methylammonium iodide (MAI):Lead (II) iodide (PbI2):Lead(II) chloride (PbCl2) are used to form MAPb2I2Cl which is a mixed halogen perovskite structure. The fabricated perovskite device containing PCBM with optimized concentration and mole ratio gives high power conversion efficiency (PCE) of 9.07% with an open-circuit voltage (Voc) of 0.91V, short circuit current density of 14.1mA/cm², and fill factor of 0.71. The lifetime characteristics and the stability are found significantly dependent on the fullerene type. The devices containing PC61BM and PC71BM are able to maintain 50% and 30% of its initial performances, respectively, even after 1100 hours. Overall, the obtained results represent an important step understanding the impacts on the p-i-n type perovskite lifetimes. [ABSTRACT FROM AUTHOR]

Bulk-heterojunction (BHJ) polymer solar cells have received a great deal of attention mainly due to the possibility of higher power conversion efficiency for photovoltaic applications. Therefore, in this study, relatively novel polymer BHJ solar cells are proposed (ITO/ETL/PTB7:PC70BM/PEDOT:PSS/Au) with various electron transport layers (ETL) such as zinc oxysulfide (Zn(O,S)), zinc selenide (ZnSe), and poly[(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide (PFN-Br). Here, each ETL material is selected based on the energy bandgap compatibility with ITO as well as the PTB7:PC70BM active layer and is based on other physical properties, which are generally required for efficient photovoltaic responses. Each proposed device is comprehensively optimized and then photovoltaic responses are simulated and compared using the software SCAPS-1D. It was observed that the ITO/Zn(O,S)/PTB7:PC70BM/PEDOT:PSS/Au device offered the highest power-conversion efficiency of up to 17.15% with an open-circuit voltage of 0.85 volts, a short-circuit current of 28.23 mA/cm2, and a fill factor of 70.69%. [ABSTRACT FROM AUTHOR]

In semi-transparent perovskite solar cells (PSCs) comprising a sputtered top electrode, the minimisation of detrimental sputter damage and/or its curing by post-processing treatment is essential to reach high efficiencies. In this work, we investigate the influence of sputter damage and post-deposition annealing steps for different electron transport layers (ETLs) in PSCs without the need of a protective buffer layer such as tin oxide deposited by atomic layer deposition. We compare solution-processed 6,6-Phenyl C61 butyric acid methyl ester (PCBM) to thermally evaporated C 60 , each in combination with a bathocuproine (BCP) layer deposited by spin coating or thermal evaporation including a thickness variation. In general, we find that C 60 is more resilient against sputter damage and thus C 60 -based cells show higher as-grown power conversion efficiencies (PCEs). Post-deposition annealing of the complete cell stack increases the PCE further to values > 16 % on 0.5 cm2 active area. However, we observe that the remaining solvent in the spin-coated PCBM layer is highly beneficial for the curing of the sputter damage during post-deposition annealing and we achieve even higher PCEs for cells incorporating solution-processed PCBM with up to > 18 % on 0.5 cm2. We show an alternative way to reach high efficiency semi-transparent perovskite solar cells without using thermally evaporated C 60 and/or a buffer layer like tin oxide deposited by atomic layer deposition (ALD). • Semi-transparent perovskite solar cells with PCE >18 % on 0.5 cm2 active area and a absorber bandgap of 1.63 eV. • No protective buffer layer like ALD-SnOx between ETL and sputtered TCO. • Curing of sputter damage with a short post-deposition annealing step at 90 °C. • Small residues of solvent in PCBM layer are detected by ToF-SIMS and are of great importance for the curing of sputter damage. • Investigating the influence of the ETL deposition method on as-grown efficiencies and post-deposition annealing behaviour. [ABSTRACT FROM AUTHOR]

Summary: Optimal interfaces play a key role in charge transport/recombination characteristics and minimized potential loss of perovskite solar cells (PSCs). Currently, n‐type oxide semiconductors are the most common electron transport layer (ETL) material, but the imperfect electronic structure, unfavorable band alignment, and corresponding poor interface of ETL/perovskite absorber remain a great challenge for achieving a high photovoltaic performance of PSCs. Here, we combine a fullerene derivative or a non‐fullerene organic semiconductor with tin(IV) oxide (SnO2) to promise much‐improved surface and electronic structure of ETL interface in Ruddlesden‐Popper perovskites (RPPs)‐based photovoltaic devices. The organic semiconductors fill a bumpy surface of SnO2 to make the surface smoother, which effectively avoids the shunt pathways at the interface of the ETL/RPP absorber layer, and thereby suppresses unintended electron‐hole recombination. The organic‐inorganic bilayered ETLs also improve the electronic structure of the SnO2 surface, which provides favorable optoelectronic properties such as quick electron extraction and elongated carrier lifetime in the device. Moreover, the hydrophobic organic semiconductor is helpful in not only growing a uniform, compact, and largely grained RPP absorber layer but also improving the stability of the perovskite absorber layer. Benefiting from the optimized bilayer ETLs, the power conversion efficiency is obviously enhanced up to 10.17% in the RPP‐based photovoltaic devices. More importantly, the bilayer ETLs allow improved long‐term stability in ambient storage of the devices, providing a viable path to design practical interfaces of efficient and stable RPP‐based PSCs. Highlights: Hybrid bilayer electron transport layer is designed to enhance the efficiency of Ruddlesden‐Popper perovskite solar cells.Phenyl‐C61‐butyric acid methyl ester and ITIC are inserted as n‐type organic semiconductors onto SnO2 film for the bilayer electron transport layer.Tailored optoelectronic properties of the bilayer electron transport layers deliver 10.17% efficiency of Ruddlesden‐Popper perovskite solar cells. [ABSTRACT FROM AUTHOR]

In this work, the detailed morphology studies of polymer poly(3-hexylthiophene-2,5-diyl) (P3HT):fullerene(PCBM) and polymer(P3HT):polymer naphthalene diimide thiophene (PNDIT) solar cell are presented to understand the challenge for getting high performance all-polymer solar cells. The in situ X-ray scattering and optical interferometry and ex situ hard and soft X-ray scattering and imaging techniques are used to characterize the bulk heterojunction (BHJ) ink during drying and in dried state. The crystallization of P3HT polymers in P3HT:PCBM bulk heterojunction shows very different behavior compared to that of P3HT:PNDIT BHJ due to different mobilities of P3HT in the donor:acceptor glass. Supplemented by the ex situ grazing incidence X-ray diffraction and soft X-ray scattering, PNDIT has a lower tendency to form a mixed phase with P3HT than PCBM, which may be the key to inhibit the donor polymer crystallization process, thus creating preferred small phase separation between the donor and acceptor polymer.

Steady‐state and time‐resolved photoluminescence (PL) and electrophotoluminescence (E‐PL) have been recorded for bulk heterojunction samples of thin films of regio‐regular poly(3‐hexylthiophene) (P3HT) and methyl [6,6]‐phenyl‐C61‐butanoate (PCBM). The PL spectra of the bulk heterojunction samples showed a monotonic decrease of PL quantum yield with increased PCBM content in the film. The PL decay was measured with both a femtosecond up‐conversion technique and a time‐correlated single‐photon‐counting technique. The mechanism of PL quenching deviated from a simple Stern‐Volmer equation, explained in terms of an apparent static quenching with a sphere‐of‐action model and dynamic quenching. With increased content of PCBM, the static quenching played a dominant role. Upon application of an electric field, the E‐PL spectra of both P3HT and bulk heterojunction samples showed an enhanced quantum yield and incremented lifetime of PL of P3HT. The long‐range electron transfer from P3HT to PCBM was retarded upon application of an electric field; the field‐induced change increased with increasing PCBM content. [ABSTRACT FROM AUTHOR]

This paper presents the study of the photoluminescent properties of molecular compositions consisting of melanin and an electron-acceptor material - fullerene derivative, [6,6]-phenyl C61 butyric acid methyl ester (PCBM). These molecular compositions have not been studied well and are promising for molecular electronics of natural materials, in particular, for organic solar cells. The novelty of this work relates to the study of photoluminescence spectra obtained for these molecular compositions and nanocomposites in various solvents (chloroform, acetonitrile, and toluene) as well as in a polystyrene matrix; these studies were carried out at various, in particular, liquid helium (4.2 K), temperatures. The obtained results allowed us to ascertain mechanisms of the state of aggregation and donor-acceptor interaction between melanin and PCBM. [ABSTRACT FROM AUTHOR]

This paper presents the production and results of optoelectronic characterization process for ITO/PEDOT:PSS/P3HT:PCBM/Al organic solar cells (OSC). OSCs were produced in open air environment with various P3HT:PCBM active layer thicknesses of 70, 110, 140, 175 and 190 nm. The diode properties of the solar cells in the dark have been investigated by using current-voltage (I-V) measurements. The absorption characteristics have been investigated by using transmission spectroscopy, and optical band gap energy (Eg) for each sample has been calculated. Solar cell parameters for each solar cell has been investigated by using current density-voltage (J-V) measurements under AM 1.5 solar raditation, and important solar cell parameters have been calculated. It was observed that fill factor (FF) value of the solar cells increase between 0.3239 and 0.3409 with decreasing diode ideality factor (n) value. The highest value of PCE was found to be 0.59, which belongs to the cell having 140 nm P3HT:PCBM thickness.

With the aim of determining the best input geometry for DFT calculations of [60]PCBM, the geometry of 24 chemically possible [60]PCBM conformers were optimised and their electronic energies and average bond strains were determined. A DFT analysis of the relevant dihedral angles provided insights into the dynamical behaviour of the ester group through sterically restricted bond rotations. In addition, the 13C NMR spectra of the six better performing conformers were simulated and compared with an experiment. There is a close correlation between average bond strain, total electronic energy and mean absolute error of the simulated 13C NMR spectra of the ester carbons. The best overall candidate conformer for the input geometry had the C61-C4, C4-C3 and C3-C2 single bonds of the alkyl chain in syn, anti and anti arrangements, respectively, and had the C2-C1 and C1-O single bonds of the ester in syn and anti arrangements, respectively. This contrasts strikingly with most representations of PCBM in the literature, which depict all relevant bonds in anti arrangements. [ABSTRACT FROM AUTHOR]

Bulk-heterojunction (BHJ) polymer solar cells have received a great deal of attention mainly due to the possibility of higher power conversion efficiency for photovoltaic applications. Therefore, in this study, relatively novel polymer BHJ solar cells are proposed (ITO/ETL/PTB7:PC70BM/PEDOT:PSS/Au) with various electron transport layers (ETL) such as zinc oxysulfide (Zn(O,S)), zinc selenide (ZnSe), and poly[(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide (PFN-Br). Here, each ETL material is selected based on the energy bandgap compatibility with ITO as well as the PTB7:PC70BM active layer and is based on other physical properties, which are generally required for efficient photovoltaic responses. Each proposed device is comprehensively optimized and then photovoltaic responses are simulated and compared using the software SCAPS-1D. It was observed that the ITO/Zn(O,S)/PTB7:PC70BM/PEDOT:PSS/Au device offered the highest power-conversion efficiency of up to 17.15% with an open-circuit voltage of 0.85 volts, a short-circuit current of 28.23 mA/cm2, and a fill factor of 70.69%.

Sun energy conversion to electrical energy using nanostructured organic/inorganic hybrid semiconductors is one of the best solutions for today’s energy crisis. In particular, researchers are focusing on multitechniques to increase the power conversion efficiency of polymer solar cells, including thermal annealing and the incorporation of metal or transition metal oxide nanoparticles (NPs) into the active layer of polymer solar cells (PSCs). The design approaches for thermal annealing are to improve the nanoscale morphology and optical properties of the active layer. The incorporation of metal NPs is based on localized surface plasmonic resonance (LSPR) effect which can be used to enhance the optical absorption in photovoltaic devices. Meanwhile, transition metal oxide NPs such as copper oxide (CuO) NPs in the active layer play a key role as light harvesting centers, charged particle hopping centers, and surface morphology developer, enabling a considerable reduction in the physical thickness of solar photovoltaic absorber layers. In this study, thermal annealing was used to optimize the power conversion efficiency of bulk heterojunction P3HT/PC70BM SCs synthesized by incorporating gold nanoparticles and copper oxide nanoparticles. Thermal annealing increased the power conversion efficiency by up to 48.3 % compared to the reference cell. The optimum short-circuit current (Jsc) of the cells was measured to be 8.704 mA/cm² compared to 5.838 mA/cm² in the reference cell; meanwhile, the external quantum efficiency (EQE) increased from 44 to 64 %. [ABSTRACT FROM AUTHOR]

A detailed first principles theoretical study of assemblies of five polymer (as donor)–PCBM (as acceptor) assemblies is presented here, with a view to assessing the potential of these organics photovoltaics (PV) in comparison to the more efficient Si-based PV cells. The geometric structures, electronic and optical properties are calculated using density functional theory (DFT) and time dependent DFT (TDDFT). Charge transfer upon absorption of light is analyzed using natural transition orbitals (NTOs). For all the polymer–PCBM assemblies studied, structural optimization leads to the polymer wrapping around the PCBM, irrespective of its initial mode of attachment to the PCBM, leading to a considerable change in the energy level spectrum of each assembly. Thus, these systems behave as molecular tweezers, which have a wide variety of applications, such as sensors. Although each polymer–PCBM assembly shows weaker absorption than the polymer-only system, the charge transfer characteristics , either direct or indirect, are excellent for all the systems. The detailed theoretical study presented in this work, considering several different properties of these polymer–PCBM assemblies in tandem, will help in understanding the viability of polymer–PCBM assemblies for use in PV applications giving pointers for improving their efficiency and providing an impetus for further experimental work on these promising systems. [Display omitted] • TD-DFT study of push-pull polymer-PCBM assemblies for photovoltaic applications. • The polymer-PCBM assemblies have been shown to act as molecular tweezers. • Use of natural transition orbitals (NTOs) for the analysis of Charge Transfer. [ABSTRACT FROM AUTHOR]

Bu çalışmada Gümüş/n-tipi Silisyum/poly[N-9′-heptadecanyl-2,7–carbazole–alt-5,5-(4′,7′-di–2–thienyl-2′,1′,3′-benzothiadiazole:[6,6]-phenyl-C61-butyric acid methyl ester/Altın (Ag/n-Si/PCDTBT:PC61BM/Au) organik metal-polimer yarıiletken Schottky bariyer diyotları, polimer arayüz olarak %20 PCDTBT ve %80 PCBM karışımı kullanılarak üretilmiştir. Üretilen diyotların 240 - 350 K sıcaklık aralığında akım-voltaj ölçümleri yapılarak, bu sıcaklıklardaki diyot idealite faktörü değerlerinin 1,80 ve 2,26 aralığında değiştiği gözlemlenmiştir. Çalışmanın ikinci aşamasında, İndiyum Kalay Oksit/PCDTBT:PCBM/Gümüş (ITO/PCDTBT:PCBM/Ag) organik güneş hücresi %20:%80 PCDTBT:PCBM hacimsel oranına sahip olacak şekilde üretilmiş ve güç dönüştürme verimi % 0,85 olarak bulunmuştur.

High-resolution (600 MHz) 1H and 13C chemical shift and 2D HETCOR NMR spectra of [60]PCBM were recorded. Resonances from every carbon atom of the ester, phenyl and cyclo-fullerenyl groups, were fully accounted. Assignments of the fullerene cyclopropa-ring, and all phenyl and ester carbons to their respective resonances were based on a HETCOR 2D NMR spectrum. Remaining fullerene assignments were made to a high level of confidence with the aid of an ωB97X hybrid HF/DFT simulation of the 13C NMR spectrum employing a triple zeta Dunning-type basis set. The best result was obtained with the range-separation parameter ω set effectively to zero. This indicates that the fraction of HF in the HF/DFT hybrid at very short range is the dominant factor in achieving good NMR results, that ωB97X with its 15.77% HF fraction at r ij = 0 seems very well suited, and that allowing the HF fraction to increase with range is not particularly beneficial. The resulting spectrum had a remarkable qualitative agreement with experiment with a very low mean absolute error for fullerene carbons of 0.09 ppm, which was considerably lower than the 0.28 ppm of the more commonly used B3LYP/6-31G(d , p) method. Image 1 [ABSTRACT FROM AUTHOR]

The dielectric properties of the Al/PCBM:ZnO/p-Si structure were investigated using the impedance spectroscopy technique. PCBM:ZnO layer was obtained by spin coating method on the p-Si. The morphological properties of the PCBM:ZnO were investigated using atomic force microscopy. The results highlighted that PCBM:ZnO thin film has uniform surfaces. The dielectric parameters such as real and imaginary parts of the electric modulus (M′ and M″) and ac electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε″), loss tangent (tan δ) values were determined. The results of the dielectric properties of the Al/PCBM:ZnO/p-Si structures impressed voltage and frequency changing. The Al/PCBM:ZnO/p-Si structures can be regarded as a candidate for organic diode applications. [ABSTRACT FROM AUTHOR]