The effect of annealing steps of spin coated Sb2S3 film in planar structure solar cells

Abstract

The inorganic Sb2S3 thin-film solar cells have increasing attention due to their merit features, which are suitable for solar cell applications. The performance of solar devices is varied based on different conditions of film deposition. The annealing temperature is an important factor in the spin-coated Sb2S3 layers because it changes from amorphous to crystalline during the preparation. Therefore, the present work was done by a step-annealing process of Sb2S3. Herein, Sb2S3 precursor was prepared by using 1 mmol of Sb2S3 and 1.5 mmol of thiourea in 1 ml of 2-methoxy ethanol and it was spin-coated at 4000 rpm on com-TiO2/FTO. Just after coating, the cells were annealed in two different conditions. For the first condition, the coated Sb2S3 was pre-heated inside the tube furnace at 160 oC for 1 minute, then again annealed at 280 oC for 10 minutes. In the second condition, the Sb2S3 was annealed in a single step at 280 oC for 10 minutes. All these annealing processes have proceeded under the N2 stream. In the cell with a two-step annealing, the desired phase was synthesized and photo-generated electron-hole pairs effectively converted. By improving the photovoltaic parameters, the power conversion efficiency (PCE) of 1.76% was achieved in a configuration of FTO/com-TiO2/Sb2S3/P3HT/Ag.