Enhanced Charge Injection and Recombination of CsPbBr3 Perovskite Nanocrystals upon Internal Heterovalent Substitution

• Published in: Journal of physical chemistry. C 2019-12, Vol.123 (49), p.29916-29921
• Main Authors: Jia, Jingna, Fu, Kena, Hou, Shifeng, Zhang, Bin, Fu, Li, Hsu, Hsien-Yi, Zou, Guizheng
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.9b10449

Heterovalent substitution of the Pb­(II) cation of CsPbBr3 perovskite nanocrystals (PNCs) with Sb­(III) cation is developed as an internal engineering strategy to tailor their optoelectrical properties. Partially replacing Pb­(II)–Br bonds of cubic CsPbBr3 PNCs with stronger Sb­(III)–Br bonds can not only enlarge the band gap and preserve the highly-passivated surface states of parent PNCs but also enable the obtained Sb­(III)–CsPbBr3 PNCs with both blue-shifted and enhanced absorbance, photoluminescence, and electrochemiluminescence as well as boosted electron and hole-injection responses via electrochemical redox. The enhanced absorbance and radiative charge transfer originate from both the increased vacancies in crystals and the impurity states in the band gap of PNCs upon substituting Pb­(II) with Sb­(III) because the increased vacancies are more favorable to recombine the electrons injected via photoexcitation and/or electrochemical redox, while suitable impurity states in the band gap of PNCs also facilitate electron transfer for charge recombination. Sb­(III)–CsPbBr3 PNCs are promising monochromatic fluorophores and electrochemiluminophores; therefore, judiciously choosing suitable internal-engineering strategy to process PNCs has promise for their extended application.