Uniform Sb2S3 optical coatings by chemical spray method

• Published in: Beilstein journal of nanotechnology 2019-01, Vol.10 (1), p.198-210
• Main Authors: Eensalu, Jako S, Katerski Atanas, Erki, Kärber, Oja Acik Ilona, Mere Arvo, Malle, Krunks
• Format: Article
• Language: English
• Subjects: Absorptivity; Antimony; antimony sulfide; Coatings; Crystallization; Deposition; Energy dispersive X ray spectroscopy; Full Research Paper; Glass substrates; Heat treatment; Island growth; Morphology; Nanoscience; Nanotechnology; Optical coatings; Optical properties; Organic chemistry; Photovoltaic cells; Polycrystals; Precursors; Raman spectroscopy; Scanning electron microscopy; Solar energy absorbers; Spectrum analysis; Spray pyrolysis; Spraying; Thickness; Thin films; Titanium dioxide; ultrasonic spray; vacuum annealing; Volmer–Weber growth; X-ray diffraction
• ISSN: 2190-4286; 2190-4286
• DOI: 10.3762/bjnano.10.18

Antimony sulfide (Sb2S3), an environmentally benign material, has been prepared by various deposition methods for use as a solar absorber due to its direct band gap of ≈1.7 eV and high absorption coefficient in the visible light spectrum (1.8 × 105 cm−1 at 450 nm). Rapid, scalable, economically viable and controllable in-air growth of continuous, uniform, polycrystalline Sb2S3 absorber layers has not yet been accomplished. This could be achieved with chemical spray pyrolysis, a robust chemical method for deposition of thin films. We applied a two-stage process to produce continuous Sb2S3 optical coatings with uniform thickness. First, amorphous Sb2S3 layers, likely forming by 3D Volmer–Weber island growth through a molten phase reaction between SbCl3 and SC(NH2)2, were deposited in air on a glass/ITO/TiO2 substrate by ultrasonic spraying of methanolic Sb/S 1:3 molar ratio solution at 200–210 °C. Second, we produced polycrystalline uniform films of Sb2S3 (E g 1.8 eV) with a post-deposition thermal treatment of amorphous Sb2S3 layers in vacuum at 170 °C,