Search

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]

This paper investigates the effect of ageing on the performance of dye-sensitized solar cells (DSCs). The electrical characterization of fresh and degraded DSCs is done under AM1.5G spectrum and the current density-voltage (J-V) characteristics are analyzed. Short circuit current density (JSC) decreases significantly whereas a noticeable increase in open circuit voltage is observed. These results have been further investigated electroanalytically using electrochemical impedance spectroscopy (EIS). An increase in net resistance results in a lower JSC for the degraded DSC. This decrease in current is mainly due to degradation of TiO2-dye interface, which is observed from light and dark J-V characteristics and is further confirmed by EIS measurements. A reduction in the chemical capacitance of the degraded DSC is observed, which is responsible for the shifting of Fermi level with respect to conduction band edge that further results in an increase of open circuit voltage for the degraded DSC. It is also confirmed from EIS that the degradation leads to a better contact formation between the electrolyte and Pt electrode, which improves the fill factor of the DSC. But the recombination throughout the DSC is found to increase along with degradation. This study suggests that the DSC should be used under low illumination conditions and around room temperature for a longer life. [ABSTRACT FROM AUTHOR]

Piecewise linear parabolic trough collector (PLPTC) is designed and developed to concentrate solar radiation on monocrystalline silicon based photovoltaicmodule. Atheoreticalmodel is used to performelectrical energy and exergy analysis of low-concentration photovoltaic (LCPV) system working under actual test conditions (ATC).Theexergy efficiency of LCPV system is in the range from 5.1% to 4.82% with increasing rate of input exergy rate from 30.81W to 96.12W, when concentration ratio changes from 1.85 to 5.17 Sun. Short-circuit current shows increasing trend with increasing input exergy rate of 0.011 A/W. Power conversion efficiency decreases from 7.07 to 5.66%, and open-circuit voltage decreases from 9.86 to 8.24V with temperature coefficient of voltage 0.021 V/K under ATC. The results confirm that the commercially available silicon solar PV module performs satisfactorily under low concentration. [ABSTRACT FROM AUTHOR]

A low-concentration photovoltaic (LCPV) system has immense potential for further cost reduction of solar photovoltaic (PV) power as compared to flat panel PV. This paper explains the performance of commercially available solar PV module mounted on parabolic trough collector experimentally and theoretically. A piecewise linear parabolic trough collector is modeled and designed to focus the solar radiation with uniform intensity on solar PV module. Silicon solar PV module based LCPV system is also modeled and simulated to study the variation of output power, open-circuit voltage, and short-circuit current with respect to module temperature and irradiance. The developed theoretical model is able to predict the performance of a LCPV system under the actual test conditions (ATCs). It was observed that the open-circuit voltage decreases from 9.86 to 8.24 V with temperature coefficient of voltage ≈-0.021 V/K under ATC. The short-circuit current of LCPV system shows increasing trend with light concentration with a rate of ≈0.285 Am2/kW. The results confirm that the commercially available silicon solar PV module performs satisfactorily up to ∼8 Sun concentration. [ABSTRACT FROM AUTHOR]