Controlled synthesis of CdTe nanocrystals for high performanced Schottky thin film solar cells

Abstract

We report the synthesis of CdTe semiconductor nanocrystals (NCs) with multi-armed, rod and tetrapod shapes, developed by a facile solution process using a cadmium carboxylate as the precursor at moderate temperatures of 220–300 °C. It was found that the size and morphology of the CdTe NCs were related to synthesis parameters such as the reaction temperature, carboxyl chain length and carboxylic acid. Based on these CdTe NCs, photovoltaic cells (PVC) in simple Schottky diode configuration of ITO/CdTe/Al were fabricated. The performances of the CdTe NCs solar cells were found to strongly rely on the morphology and surface ligand of the CdTe NCs. The best device could show a power conversion efficiency (PCE) of 5.15% under AM 1.5G illumination at 100 mW cm⁻², which is the highest efficiency of a CdTe NC-based Schottky solar cell reported to date. Notably, in comparison to the ITO/CdTe/LiF/Al device, the device configuration of ITO/CdTe/Al showed higher efficiency and better air-stability.