CdS-carbon black hybrid nanocomposite buffer layer for antimony sulfide solar cells

Abstract

Hydrothermal synthesis of antimony sulfide (Sb2S3) has emerged as a suitable method to fabricate Sb2S3 solar cells. Conventionally, a CdS film is essential to obtain homogeneous and high-quality Sb2S3 films, which in turn improves the photovoltaic performance of Sb2S3 devices. However, the CdS film also requires a post-treatment process to achieve the desired electronic conductivity. Herein, we report a hybrid nanocomposite buffer layer consisting of CdS and carbon black nanoparticles synthesized on a TiO2 film by a one-pot chemical bath deposition route. This method enables high electrical conductivity of the buffer layer with low roughness and n-type nature. Thus, devices based on the nanocomposite buffer layer improve the junction quality at the buffer layer/Sb2S3 interface, reducing the trap state recombination. As a result, the power conversion efficiency of the Sb2S3 solar cell increases from 4.95 to 6.03%. Such improvement demonstrates that using the nanocomposite buffer layer is a facile and efficient approach to reduce the need for a post-treatment process of CdS.