A first-principles study on the optoelectronic properties of mixed-halide double perovskites Cs2TiI6−xBrx. (3rd August 2020)

• Record Type: Journal Article
• Authors: Liu, Diwen; Zha, Wenying; Yuan, Rusheng; Chen, Jianming; Sa, Rongjian
• Is Part Of: New journal of chemistry. Volume 44:Number 32(2020)
• Page Start: 13613
• Page End: 13618
• Publication Date: 2020-08-03
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d0nj02535f
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : All-inorganic double perovskites as promising photovoltaic materials have received great attention in recent years. Abstract : All-inorganic double perovskites as promising photovoltaic materials have received great attention in recent years. In this work, the structural, mechanical, electronic, and optical properties of mixed-halide double perovskites Cs2 TiI6− x Br x ( x = 0, 2, 4, and 6) were studied by using first-principles calculations. The calculated lattice parameters of Cs2 TiI6− x Br x agree well with the reported experimental values. The calculated results have confirmed that these compounds are thermodynamically stable. Moreover, these mixed-halide double perovskites can easily be converted into thin films based on their unique mechanical properties. The obtained band gaps of the Cs2 TiI6− x Br x systems using the PBE+ U method have better matched with the experimental values. When the Br content increases, the band gap of Cs2 TiI6− x Br x increases gradually, which leads to a decreased optical performance in the visible light region. Based on a suitable direct band gap and strong absorption coefficient, Cs2 TiI2 Br4 is an ideal potential material for single-junction solar cells.