Investigation of CsBr:BiBr3 precursor ratio concentration on cesium bismuth bromide perovskite formation

• Main Authors: Low, Yiin Jian, Liew, Josephine Ying Chyi, Talib, Zainal Abidin, Lim, Hong Ngee, Kamarudin, Mazliana Ahmad, Choo, Thye Foo, Fen, Yap Wing, Lee, Han Kee, Salisu, Bashir, Shitu, Ibrahim Garba
• Format: Article
• Published: Elsevier BV 2023
• Online Access: http://psasir.upm.edu.my/id/eprint/108893/; https://linkinghub.elsevier.com/retrieve/pii/S0301010422003445
• Institution: Universiti Putra Malaysia

The effect of precursor ratios on the formation of Cs3Bi2Br9 via a re-precipitation synthesis method has been studied thoroughly. X-ray diffraction analysis showed that the precursor ratio was critical for the Cs3Bi2Br9 phase formation. The Cs-rich or Bi-rich precursor ratio resulted in diverse perovskite structure formation of Cs3BiBr6 and Cs3Bi2Br6 with micron size platelet and semi-micron size crystal morphology respectively. Unreacted BiBr3 precursor remains in the supernatant solution under Bi-rich conditions. The synthesized powder dispersed in toluene shows the degradation of the Cs3Bi2Br9 phase at Cs-rich conditions. Photoluminescence quantum yield (PLQY) of 0.73 % was identified in Cs3Bi2Br9 with a large contribution to the exciton-related recombination process. A precursor ratio CsBr:BiBr3 of 3.0:2.0 is proposed to form a single-phase Cs3Bi2Br9 structure, as the deviation in precursor ratio would promote the Cs3BiBr6 structure growth and affect the material’s optical performance.