Thin film solar cell based on CuSbS2 absorber prepared by chemical bath deposition (CBD)

Abstract

CuSbS2 has been proposed as an alternative to other absorber materials, such as CIGS, because it’s an earth abundant, low cost and nontoxic material; also, its suitable band gap and high absorption coefficient has a potential application in photovoltaic devices. This work reports the CuSbS2 thin films preparation and characterization, grown by a one-step chemical bath deposition using thin films which were heat treated at 350, 380 and 400°C. X-ray diffraction analysis showed the formation of orthorhombic CuSbS2 after the films heating. The band gap energy value of the CuSbS2 decreased from 1.96 to 1.54eV due to the heat treatment at 350–400°C. The CuSbS2 films showed p-type conductivity and XPS spectrum shows the oxidation states of the elements in the obtained thin films. The films which were heat treated at 380°C showed a good crystalline and improved phase purity. The material was incorporated into a SnO2:F/CdS/Sb2S3/CuSbS2/C:Ag structure to evaluate its potential application as absorber in a solar cell achieving an encouraging 0.66% of conversion efficiency with 0.382V of Voc, 5.32mA/cm2 of Jsc and 32% of FF.