Ti-Alloying of BaZrS3 Chalcogenide Perovskite for Photovoltaics

Xiucheng Wei; Haolei Hui; Samanthe Perera; Aaron Sheng; David F Watson; Yi-Yang Sun; Quanxi Jia; Shengbai Zhang; Hao Zeng

doi:10.1021/acsomega.0c00740

Ti-Alloying of BaZrS₃ Chalcogenide Perovskite for Photovoltaics

ACS Omega. 2020 Jul 24;5(30):18579-18583. doi: 10.1021/acsomega.0c00740. eCollection 2020 Aug 4.

Authors

Xiucheng Wei¹, Haolei Hui¹, Samanthe Perera¹, Aaron Sheng², David F Watson², Yi-Yang Sun³, Quanxi Jia⁴, Shengbai Zhang⁵, Hao Zeng¹

Affiliations

¹ Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States.
² Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States.
³ State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China.
⁴ Department of Materials Design and Innovation, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States.
⁵ Department of Physics, Applied Physics & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States.

Abstract

BaZrS₃, a prototypical chalcogenide perovskite, has been shown to possess a direct band gap, an exceptionally strong near band edge light absorption, and good carrier transport. Coupled with its great stability, nontoxicity with earth-abundant elements, it is thus a promising candidate for thin film solar cells. However, its reported band gap in the range of 1.7-1.8 eV is larger than the optimal value required to reach the Shockley-Queisser limit of a single-junction solar cell. Here, we report the synthesis of Ba(Zr_1-x Ti _x )S₃ perovskite compounds with a reduced band gap. It is found that Ti-alloying is extremely effective in band gap reduction of BaZrS₃: a mere 4 atom % alloying decreases the band gap from 1.78 to 1.51 eV, resulting in a theoretical maximum power conversion efficiency of 32%. Higher Ti-alloying concentration is found to destabilize the distorted chalcogenide perovskite phase.