Hot injection synthesis parameters effects on the structure, crystallinity, microstructure and optical properties of Sb2S3 nanopowders

Abstract

Antimony sulfide amorphous and crystalline nanoparticles were synthesized by the hot-injection method. X-ray diffraction analysis confirmed the gradual growth and crystallization of amorphous particles with synthesis time and temperature. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed spherical shapes of amorphous nanoparticles of 10–50 nm in radius and clothespin-shaped crystalline particles with a radius and length of several micrometers and an approximate aspect ratio of 2.5. Diffuse reflectance spectroscopy (DRS) implied a 1.8–2.0 eV, size-tunable, indirect band gap for the amorphous phase and a smaller, ∼1.6 eV, direct band gap for the crystalline phase. Thermogravimetry (TG/DSC) and Fourier-transform infrared (FTIR) spectroscopy studies show that amorphous powders have a low concentration of organic molecules, which are primarily eliminated during crystallization. The powders were spray deposited as an absorber layer in ITO/TiO2 + Sb2S3/P3HT/I2(I−)/Al-composed solar cells, giving up to 1.2 % energy conversion efficiency when illuminated by a 290 W/m2 tungsten lamp as a source.