Antimony Chalcogenides Based Thin-Film Solar Cell

Abstract

AbstractThin-film solar cell technology is now one of the major focuses of research mainly due to CIGS and CdTe solar cells which have efficiency more than 20%. The main limitation is lying with the low abundance of In and Te and the toxicity of Cd, among these materials which is the bottleneck to use these materials as an absorber layer for solar cell. As a replacement, new materials like CZTS, CTS, SnS, and Sb2S3/Se3 are emerging and studied as absorber material for thin-film solar cells by the research community. These semiconductors have the advantages like p-type conductivity, high absorption coefficient, and suitable direct bandgap to be used as a thin-film absorber layer material. CZTS, the most researched material, obtained efficiency of 12.6%, but defects, appearance of secondary phases, and phase complexity are the major drawbacks for this material to improve its efficiency. For the last few years, instead of a lot of research to improve the efficiency, no significant enhancement of efficiency is achieved. So the research community is concentrating now on other binary materials which actually showing improved performance in terms of solar cell efficiency. Thin-film antimony chalcogenides, i.e. Sb2S3/Se3 recently appearing as an emerging topic of interest among the researchers. Sb2S3/Se3, a V-VI semiconductor, possess excellent optoelectrical properties like high absorption coefficient (>105 cm−1), tunable bandgap (1.04–1.67 eV), intrinsic p-type conductivity, decent carrier mobility (9–15 cm2/V.s), low toxicity, moisture, and air stability. Hence, these materials are very much suitable for the application in various optoelectronic fields. Apart from the above advantages, these materials have other added advantages like earth abundance, less structural complexity, less appearance of other secondary phases, and low melting point. Recent studies show that Sb2S3/Se3 obtained considerable momentum in its research and achieved record efficiency of 7.5% and 9.2%, respectively. Though the research is concentrating on its promising aspects of improvement in efficiency, in actual it is still behind the Shockley–Queisser (S-Q) limit of efficiency and also far lower than the reported efficiency of CdTe and CIGS solar cells. The main obstacles in obtaining high efficiency for antimony chalcogenide solar cell are non-ideal series and shunt resistance, deep defects, non-radiative and interface recombination, interdiffusion between layers, etc. This chapter is divided into three sections: firstly different deposition techniques (vacuum and non-vacuum) to have good-quality Sb2S3/Se3 thin film; secondly, progress made till now in terms of photo conversion efficiency, and thirdly, analysing the Sb2S3/Se3-based photovoltaic devices, identifying their main limitations, and providing insights for improving current device performance will be discussed.