Low Temperature Photoluminescence Properties of α‐CsPbI3 Nanocrystals with High Quantum Yield. Issue 10 (15th August 2022)

• Record Type: Journal Article
• Authors: Sun, Chunyu; Wang, Xinzhan; Qiu, Pengfei; Mou, Xuejiao; Lu, Wanbing; Teng, Xiaoyun; Fu, Guangsheng; Yu, Wei
• Is Part Of: Crystal research and technology. Volume 57:Issue 10(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-15
• Subjects: CsPbI3 nanocrystals -- low temperature photoluminescence -- thermal transfer; Crystallography -- Periodicals; 548
• DOI: 10.1002/crat.202100243
• Languages: English
• ISSNs: 0232-1300

Abstract

Abstract: Temperature‐dependent photoluminescence (PL) properties of high quality cubic phase α‐CsPbI3 nanocrystals are investigated, and thermal transfer from free excitons to trapped excitons is observed. Free exciton recombination is the main origin of the high PL quantum yield (97%) at room temperature. Little change of PL peak energy is observed with decreasing temperature from 280 to 200 K, and it shifts from 1.84 to 1.81 eV in the region of 200 and 80 K. The PL peak intensity decreases with decreasing temperature first and then increases, and the minimum value is observed at 180 K. Two PL bands are obtained by Gaussian fittings in the PL spectra detected at different temperatures, and the high energy band is attributed to the emission of free excitons, while that for the low energy band is related to the transition of trapped excitons. The PL integrated intensity ratio of trapped exciton and free exciton transition increases from 0.18 to 2.10 with decreasing the temperature, which suggests that thermal transfer from free exciton to trapped exciton states leads to the dominant optical emission of trapped exciton recombination in the low temperature region. Abstract : Temperature‐dependent photoluminescence properties of high quality cubic phase CsPbI3 nanocrystals are investigated. Free exciton recombination is the main origin of the high photoluminescence quantum yield (97%) at room temperature, and thermal transfer from free exciton to trapped exciton states leads to the dominant optical emission of trapped exciton recombination in the low temperature region.