Issue 60, 2020

Indirect-to-direct band gap transition and optical properties of metal alloys of Cs2Te1−xTixI6: a theoretical study

Abstract

In recent years, double perovskites have attracted considerable attention as potential candidates for photovoltaic applications. However, most double perovskites are not suitable for single-junction solar cells due to their large band gaps (over 2.0 eV). In the present study, we have investigated the structural, mechanical, electronic and optical properties of the Cs2Te1−xTixI6 solid solutions using first-principles calculations based on density functional theory. These compounds exhibit good structural stability compared to CH3NH3PbI3. The results suggest that Cs2TeI6 is an indirect band gap semiconductor, and it can become a direct band gap semiconductor with the value of 1.09 eV when the doping concentration of Ti4+ is 0.50. Moreover, an ideal direct band gap of 1.31 eV is obtained for Cs2Te0.75Ti0.25I6. The calculated results indicate that all the structures are ductile materials except for Cs2Te0.50Ti0.50I6. Our results also show that these materials possess large absorption coefficients in the visible light region. Our work can provide a route to explore stable, environmentally friendly and high-efficiency light absorbers for use in optoelectronic applications.

Graphical abstract: Indirect-to-direct band gap transition and optical properties of metal alloys of Cs2Te1−xTixI6: a theoretical study

Article information

Article type
Paper
Submitted
04 sen 2020
Accepted
28 sen 2020
First published
06 okt 2020
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2020,10, 36734-36740

Indirect-to-direct band gap transition and optical properties of metal alloys of Cs2Te1−xTixI6: a theoretical study

D. Liu, W. Zha, R. Yuan, B. Lou and R. Sa, RSC Adv., 2020, 10, 36734 DOI: 10.1039/D0RA07586H

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements