Highly Efficient CdSe Quantum Dot-Sensitized Solar Cells via a Facile SILAR Method: Dependence of the SILAR Cycles on Optical Properties and Photovoltaic Performance

Abstract

This work emphasizes using CdSe as a sensitizer in quantum dot-sensitized solar cells (QDSSCs) due to its beneficial band alignment with TiO2, enhancing effective charge injection. This study presents highly efficient CdSe QDSSCs developed using the successive ionic layer adsorption and reaction (SILAR) method. The XRD analysis revealed a hexagonal crystal structure for the synthesized CdSe quantum dots (QDs) with an average particle size of 9.2 nm. Increasing the SILAR cycles from 3 to 5 showed a decrease in the energy bandgap, reducing it from 1.79 eV to 1.68 eV, as observed in the investigation of optical properties. The optimal photovoltaic performance of CdSe QDSSCs was achieved at 4 SILAR cycles, yielding a notable power conversion efficiency (PCE) of 6.77% (Jsc = 14.63 mA/cm2, Voc = 0.71 V, FF = 65.2%), which is higher than that of a previous report of SILAR-prepared CdSe QDSSCs.