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In the present study, the role of active and transport layer materials in the degradation mechanism is studied using different device geometries. Initially, the absorbance of the active layer materials as a function of the degradation time is compared with the photovoltaic characteristics. Also, it has been found that the hole- and electron-transport layers play a pivotal role in the degradation process for the observed decreased device efficiency. The theoretical charge-transport model complements these experimental photovoltaic parameters well. The results are attributed to the change in the quasi-Fermi level, and exciton splitting for the fresh and aged devices. These interesting and impactful results reveal a basic understanding of the degradation mechanism for the P3HT:PC71BM and PTB7:PC71BM blend systems and provide insights for achieving long-term stability in such solar-cell devices. [ABSTRACT FROM AUTHOR]

Organic–inorganic perovskites photovoltaic materials are considered as one of the promising candidates for the emerging photovoltaic (PV) sector. It has drawn tremendous attention from fundamental research and PV industries, due to its high efficiency, chemical properties, and low fabrication cost. But, its lifetime under real field operation is always the major obstacle toward commercialization. Potential‐induced degradation (PID) is known as the common reliable threat in the established commercial PV technologies which lead to catastrophic failure within a short time. Thus, it is essential to enable reliability assessment of PID on the precommercial development stage of perovskite photovoltaics to further enrich the confidence by identifying, eliminating, and developing an understanding of the possible degradation mechanism in the field condition. In this article, different architecture‐based perovskite solar cells are studied to reveal the degradation mechanism under PID for the first time. The results show that PSCs of n–i–p with a phenyl C61 butyric acid methyl ester (PCBM) layer have good stability under PID compared with other treated structures with only 4% degradation after 18 h. [ABSTRACT FROM AUTHOR]

Solution processed hole transport layer based on graphene oxide (GO) and molybdenum oxide (MoO3) composite in bulk heterojunction organic solar cell (OSC) devices offer low cost, improved performance compared to conventional organic solar cells. Here, we have made a study comparing the power conversion efficiency (PCE) of this composite to the pristine GO and MoO3 as a hole transport layer in the organic photovoltaics. The devices with the composite shows optimized performance with PCE of ∼ 5.1%, while the pristine GO and MoO3 display 1.59% and 2.5%, respectively. These differences are attributed to the lower short circuit current (Jsc) and thereby lower fill factor (FF) with respect to the GO and MoO3. Nevertheless, the composite based devices exhibits improved optical absorption and photoluminescence quenching as compared to pristine interface layer. This study intends to highlight efficient modulation of the interface barrier of hole transport layer which allow us to give faster transport and extraction of the charge carrier efficiently at the electrodes. [ABSTRACT FROM AUTHOR]

Recent increase in the global consumption of pharmaceutical compounds has enhanced the economic burden for the human population and increased the accumulation of these pharmaceutical compounds in the environment via wastewater released from treatment plants to various water bodies, such as groundwater and surface water, which poses a severe threat to human health as well as aquatic and terrestrial life. Several conventional treatment techniques available to remove industrial pharmaceutical-active compounds (PACs), such as ozonation, photolysis, photocatalysis, and wetland treatment, for the remediation of wastewater resources. Owing to their unique physicochemical features, natural abundance, and the ability to substitute noble metal catalysts, MoS 2 -based hetero-nanostructured materials have attracted significant interest. This study provides a brief overview of the recent research on the structural properties and synthesis of MoS 2 -based heterojunctions, i.e., traditional type-II, all-solid-state, direct Z-scheme and S-scheme heterojunction photocatalytic systems. The layered 2D structure of MoS 2 -based materials contributes to the high mobility of the photoinduced charge carriers, which makes photodegradation rapid and highly stable. These innovative materials have high surface area, small size, photosensitivity, tunable pore size, and electrochemical and magnetic properties. The large-scale application of MoS 2 as a single semiconductor material remains limited. Essentially, a mechanistic investigation on the separation of photoinduced charge carriers and possible approaches to improve the photooxidative potential of MoS 2 with a maximum recovery rate are needed. Moreover, piezocatalytic route for remediation of the hazardous pharmaceutical is addressed. Finally, a brief, conclusive remark regarding current studies and the unresolved challenges of MoS 2 -based photocatalysts addressing future research. [Display omitted] • MoS 2 and its composites promote photochemical/photoelectrochemical PACs degradation. • MoS 2 in corroboration with peroxides promote decomposition of PACs pollutants. • MoS 2 and its composites promotes PACs degradations via PDS/PMS activation. • MoS2 and its composites promote piezocatalytic PACs abatement. [ABSTRACT FROM AUTHOR]

In the present study, a novel solution-processable 1,6,7,10-tetramethylfluoranthene (1), as the smallest fragment of fullerene, is synthesized and systematically studied for use as a non-fullerene acceptor in an organic solar cell (OSC). Molecule 1 has the potential to be synthesized on a large scale. Optical and electrochemical studies revealed that 1 has a high absorption range and an appropriate band gap, which is compatible with poly(3-hexylthiophene-2,5-diyl) (P3HT) as a donor. The morphology showed high intermixed blend with uniform distribution of donor–acceptor molecules. Steady state and time resolved photoluminescence studies showed efficient charge separation from the donor and acceptor. These studies can be confirmed by the conventional OSC device structure employing a blend of P3HT:1, which gives a power conversion efficiency (PCE) of up to 0.71% with an open circuit voltage (VOC) of 0.52 V and a fill factor (FF) of 44.89%. Despite this, the significant stability of the device, even after 60 h in open air, demonstrates that this molecule shows promising output and the result can be enhanced in the future with further optimization. [ABSTRACT FROM AUTHOR]

This article describes a silicon quantum dot (Si QD) solar cell with absorption enhancement due to quantum-confinement in the front-side emitter region, which helps in the improvement of the short-circuit current density. The Si QD solar cell is theoretically mimicked using an equivalent circuit to account the possible recombination losses under low concentration illumination. The electrical output is estimated using proposed theoretical model by considering the fundamental properties of intrinsic Si reported in the literature. An increase of ∼7.5% in generated current density is observed due to extra absorption of incident radiation through Si QD, which is in accordance with the experimental findings. The performance of Si QD/c-Si solar cell has been studied with respect to low concentration illumination, wherein with increasing CR from 1 sun to 5 suns, the short circuit current density increases from 29.4 to 147.2 mA/cm 2 and the open circuit voltage increases from 0.565 to 0.609 V. This study provides a theoretical framework for design optimization of a future Si QD solar cells to achieve better performance of the device. [ABSTRACT FROM AUTHOR]

Commercially available polycrystalline silicon solar cells have been studied under varying illumination conditions to evaluate their application in low-concentration photovoltaic systems. The present work explores a detailed analytical framework for determining a broad range of performance indicating parameters for polycrystalline silicon solar cells by using the impedance spectroscopy (IS) technique. The IS measurements show that the diffusion capacitance varies from 1×10 −7 to 5×10 −7 F/cm 2 and diffusion resistance from 0.5 to 770 Ω-cm 2 with the applied bias. The IS measurements also indicated that the effective lifetime of charge carriers decreases with increasing illumination. This study confirms that commercially available polycrystalline silicon solar cells can work satisfactorily under low concentration (<3.5 suns). [ABSTRACT FROM AUTHOR]

A solid-state mesoporous titanium dioxide (mTiO 2 ) layer based hetero-junction solar cell, employing nanoparticles (NPs) of methyl ammonium lead iodide perovskite (CH 3 NH 3 PbI 3 ) as light harvesters has been studied. The optimum performance parameters of CH 3 NH 3 PbI 3 are observed as a function of sintering temperature and confirmed by X-ray diffraction analysis and UV–vis spectrophotometry. A solid-state solar cell with the sandwich structure of mTiO 2 /CH 3 NH 3 PbI 3 /Graphite paste showed a power conversion efficiency of 1.11% tested under standard Air Mass 1.5 Global (1000 W m −2 , AM1.5G) solar spectrum. Two-diode model is used to explore the performance limiting factors of the developed solid-state perovskite solar cell. [ABSTRACT FROM AUTHOR]

In recent years, metal halide perovskite solar cells have become a major competitor in the run to lower the levelized cost of electricity (LCOE) of photovoltaic (PV) systems. Commercialization of this new technology mainly depends on the long‐term stability of such devices, for which potential‐induced degradation (PID) may represent a factor of detrimental impact. As PID can trigger rapid and significant losses in PV systems, it is generally considered among the most critical failure modes with a high financial repercussion. Herein, the results of PID tests on perovskite solar cells are reported for the very first time. The solar cells are found to be extremely susceptible to PID: 18 h of high‐voltage stress, according to the PID test standard IEC 62804‐1 TS (foil method at 60 °C), shows a performance degradation of up to 95%, which mainly results from a decrease in the short‐circuit current. These results also uncover near full PID recoverability and pave the way toward further research into its mechanisms, kinetics, and mitigation. [ABSTRACT FROM AUTHOR]

This work describes the role of relative humidity (R.H.) on the performance degradation of methyl-ammonium lead-iodide (CH 3 NH 3 PbI 3 ) based hole transport material (HTM) free hetero-junction perovskite solar cell. It has been observed that the power conversion efficiency (η) of perovskite solar cells decreases from 4.52% to 1.28% with increases in R.H. from <40% to 75%. A semi-analytical optoelectronic model is further developed to explore the effect of humidity on performance limiting parameters, i.e. absorption coefficient, diffusion length. The shunt resistance decreases whereas space charge region width and series resistance increases with respect to the increase in R.H. from <40% to 75%. The charge carrier losses through recombination, spatial relaxation and thermalization are also analysed and found to increase from 76% at <40%R.H to 84% at 75%R.H. [ABSTRACT FROM AUTHOR]

A perovskite heterojunction solar cell is fabricated with architecture of hole transport material (HTM) free discrete electrode. The morphological, structural and optical properties are studied by FESEM, XRD and UV–Vis spectrophotometry techniques. A single diode model has been used to investigate the cell characteristics. The interface between TiO 2 and CH 3 NH 3 PbI 3 layer is found analogous to Schottky diode that acts as a heterojunction for excitation and dissociation of charge carriers due to the existence of an internal electric field at the junction. The SCAPS simulation is done to explore the role of interface defects and band offsets. Device simulation has shown an improvement of 16%, 6% and 25% in V OC , FF and η respectively with incorporation of the HTM layer in device structure. [ABSTRACT FROM AUTHOR]

The present work describes a method for the development of hole-transport material (HTM) free, solution processable perovskite solar cell under ambient air conditions. This study mainly focuses on the working mechanism of the perovskite solar cell using impedance spectroscopy and current–voltage ( I – V ) techniques. Impedance spectroscopy reveals various interfacial processes in terms of resistive and capacitive elements, which provided an insight into the charge transport through the junction and bulk of the FTO–perovskite solar cell. The study also provides a new architecture of pervoskite solar cell, where in conducting polymer (poly-aniline) as a hole-extraction electrode increases the efficiency by 21% relative to FTO electrode. This article systematically explains the bridging and trapping effects within the perovskite solar cells for the first time. [ABSTRACT FROM AUTHOR]