• Energy Research

Abstract Thermoplastic polyolefin (TPO) is a newly developed non-crosslinking material for photovoltaic (PV) module lamination as an alternative to ethylene–vinyl-acetate (EVA) encapsulant. This article assesses its applicability as an encapsulant material. We report the results of various characterization tests for discoloration, optical, and thermal properties degradation before and after the UV accelerated test. To evaluate its weathering stability, the UV-365 acceleration test has been conducted on the glass to glass TPO laminate, with EVA as a benchmark. In 50 days of weatherability tests, the transmittance of EVA significantly reduced while TPO remained almost unchanged. The discoloration of TPO is around nine times slower than that of EVA. The analytical tools like Raman spectroscopy, fluorescent imaging, and spectra have been used to assess the degradation behavior, which indicates a clear difference between EVA and TPO based encapsulant. Thermal properties (glass and melt transitions) of TPO and EVA have been studied through heat-cool-heat cycle testing by differential scanning calorimeter (DSC). This test confirmed that TPO thermal properties remain almost unchanged, whereas EVA shows significant changes after 50 days of UV exposure. In the thermogravimetry analysis (TGA) results, we found that TPO is stable till a significantly higher temperature than EVA. Additionally, the 180° peel adhesion test suggests that TPO has a higher adhesion strength than EVA. This work will help in understanding the applicability of newly developed non-crosslinking TPO as a potential replacement for EVA for the PV modules.

Abstract CZTS, is a good absorber material which also shows electrocatalytic behavior thus making it a suitable candidate for use as counter electrode for DSSCs. At the same time it is the long term stability of the counter electrode which is the primary motivation for carrying out this work. Herein, CZTS is electrodeposited on FTO coated glass and used as counter electrode to fabricate DSSCs. Sealed DSSCs were subjected to ageing in dark and under illumination at room temperature and cells were examined periodically using I-V and EIS measurements. CZTS counter electrode based DSSCs showed relatively stable performance after 120 days of ageing under illumination with slight decrement in the electrocatalytic activity of CZTS.

Abstract Photovoltaic conversion technologies took the opportunity to trap the abundant solar energy, but soiling reduces these device's energy yield. In this endeavor, we developed a novel anti-soiling coating with excellent weather stability to counter the challenges posed by soiling. The developed anti-soiling coating characteristics like ambient condition curablity, good mechanical and weather stability to encounter the real field conditions are because of the bonding of functionalized hybrid Zr-O-Si network with the glass. The X-ray photoelectron spectroscopy, FTIR, and Raman spectroscopy analysis indicate the presence of the functionalized hybrid Zr-O-Si network in the coating. The coating exhibited good thermal stability up to 150 °C and observed a minimal decrement of

AbstractCu2ZnSnS4 (CZTS) has emerged as a potential candidate in optoelectronic devices due to its non-toxicity, low cost and abundance of its constituents in earth's crust. Conventional CZTS synthesized techniques are either energy intensive or use toxic chemical. A modified, low temperature solid state reaction route for synthesis of CZTS nanoparticles using metal acetates, thiourea and SnCl2 is demonstrated. Synthesis of stoichiometric amount of these precursors at 250°C for 1h is sufficient to form single phase. Synthesised powder was characterized by means of X-ray diffraction (XRD), Raman spectroscopy and Transmission Electron Microscopy (TEM) and UV–visible (UV–vis) absorption spectrumm. Band gap of as prepared CZTS was found to be around 1.45eV, which is appropriate for use as absorber layer in a thin film solar cell.

Abstract Dye sensitized solar cells (DSSCs) are a low cost alternative to silicon-based and thin film solar cells. Usually DSSCs utilize platinum to catalyze the iodine redox couple and complete the electric circuit. Though, platinum is an excellent catalytic material for use in preparation of counter electrodes (CEs) for DSSCs but it is expensive. Alternatives to replacement of platinum (Pt) that have been examined are carbon materials, conductive polymers. In this work, counter electrode for DSSCs was fabricated using carbon material obtained from carbonization of sugar free at high temperature. Slurry of the carbon produced by carbonization was made with polyvinylpyrrolidone (PVP) as a surfactant and a coating was obtained by doctor blading the slurry over the FTO glass substrate. The DSSCs based on produced carbon CE show a maximum power conversion efficiency of 6.72% (area 0.25 cm 2 ), which is comparable to 8.19% of the cell with the conventional Pt CE at the same experimental conditions. The current density (Jsc) and open circuit voltage (V OC ) of the DSSCs was 17.10 mA cm −2 and 0.66 V respectively.

Contact layers play an important role in thin film solar cells, but new material development and optimization of its thickness is usually a long and tedious process. A high-throughput experimental approach has been used to accelerate the rate of research in photovoltaic (PV) light absorbers and transparent conductive electrodes, however the combinatorial research on contact layers is less common. Here, we report on the chemical bath deposition (CBD) of CdS thin films by combinatorial dip coating technique and apply these contact layers to Cu(In,Ga)Se2 (CIGSe) and Cu2ZnSnSe4 (CZTSe) light absorbers in PV devices. Combinatorial thickness steps of CdS thin films were achieved by removal of the substrate from the chemical bath, at regular intervals of time, and in equal distance increments. The trends in the photoconversion efficiency and in the spectral response of the PV devices as a function of thickness of CdS contacts were explained with the help of optical and morphological characterization of the CdS thin films. The maximum PV efficiency achieved for the combinatorial dip-coating CBD was similar to that for the PV devices processed using conventional CBD. The results of this study lead to the conclusion that combinatorial dip-coating can be used to accelerate the optimization of PV device performance of CdS and other candidate contact layers for a wide range of emerging absorbers.

Abstract An earth-abundant and relatively less toxic, quaternary Cu2ZnSnSe4 (CZTSe) quantum dots (QDs) were prepared by hot injection method at low temperature to use as a sensitizer for QDSC. The formation of tetragonal phase and stoichiometry were confirmed by X-ray diffraction (XRD), Raman spectroscopy and energy dispersive X-ray (EDX) analysis, respectively. The UV–Vis-NIR and photoluminescence spectroscopy was used to determine the bandgap (1.66 eV) and narrow emission (1050–1130 nm) range. Moreover, transmission electron microscopy (TEM) was used to find out the average size of CZTSe QDs and it was found to be ∼5 nm. It can highly adsorb on the porous TiO2 nanofibers (NFs) and enhance the absorbance due to its smaller size. The photoconversion efficiency was investigated using the prepared CZTSe QDs sensitized porous TiO2 NFs based QDSC and its photoconversion efficiency (PCE) was found to be 3.61% which is higher than that of the conventional TiO2 NFs based QDSC (η ≈ 2.84%).