Modification of polysulfide electrolyte by applying various amines, thiourea and urea as efficient additives to improve photovoltaic performance of quantum dot-sensitized solar cells

Abstract

In this study, for the first time we reported a low-cost and straightforward method to modify the polysulfide electrolyte using amine additives including aromatic amines (1,8-naphthalenediamine, 1,5-naphthalenediamine), linear amines (ethylenediamine, diethylamine, ethylamine, tert-butylamine, and butylamine), thiourea, and urea in the polysulfide electrolyte system to improve the CdS/CdSe QDSSCs performance. The photovoltaic data showed that the highest power conversion efficiencies (PCEs) were obtained for 1,5-naphthalenediamine amongst aromatic amine groups, diethylamine amidst linear amine groups and thiourea. The best-measured PCE was 3.42% (JSC = 18.98 mA·cm−2, VOC = 0.50 V, FF = 0.36) at AM1.5, which was due to presence of thiourea additive in the polysulfide electrolyte. The results of data revealed that the interaction between thiourea additive, TiO2, and redox couple in the electrolyte solution caused to a molecular complex formation, increase the electron lifetime (τ), JSC and, ultimately, improve the PCE value compared to other additives under investigation in this study.