The impact of pre-annealing temperature on the performance of sb2s3 film in planar solar cell structure

Abstract

Sb2S3 has recently been widely used as a light-harvesting material in thin-film solar cells due to its exciting optical and electrical properties. Various strategies such as different precursor solutions and vacuum and non-vacuum deposition have been used to enhance the photovoltaic properties. Since the temperature impacts the optical absorption and crystallization of Sb2S3 films, the performance of the devices could be improved by the annealing temperature. This work aims to investigate the solar cell’s performance based on pre-annealing temperature. In this work, the Sb2S3 precursor was prepared by dissolving thiourea and SbCl3 in 2- methoxyethanol and spin-coated on a dense compact TiO2 (c-TiO2) layer at 4000 rpm for 30 s. Coated Sb2S3 films were pre-annealed at 155, 170, 185, and 200oC for 1 minute. After getting cool down, these thin films were annealed at 280oC for 10 mins in the tube furnace under the N2 stream. This system used compact TiO2 and P3HT as electron and hole transport materials, respectively. By increasing the annealing temperature, the devices were analyzed using UV-Vis absorption spectroscopy, Current Density-Voltage (J-V) measurement, Incident Photon to current conversion efficiency (IPCE), X-ray diffraction (XRD), and Impedance (EIS). The well-defined crystallization structure (Stibnite) of Sb2S3 was obtained in our study. The photovoltaic parameters were enhanced by increasing the pre-annealing temperature up to 185oC as 10.6-14.2 mA/cm2 of Jsc, 433-526.1 mV of Voc, and 31-41% of FF. The IPCE spectra were in very good agreement with the short circuit current of the devices, showing the highest EQE of 55%, and the series and charge transfer resistances data supported the performance changes with pre-annealing temperature. The performance of the Sb2S3 solar cell can preciously be controlled by pre-annealing temperature, due to changes in optical and electrical properties and the device fabricated at 185oC harvested the sunlight effectively with 3.04% of efficiency