Enhanced Size Selection in Two-Photon Excitation for CsPbBr₃ Perovskite Nanocrystals

Summary, in English

Cesium lead bromide (CsPbBr₃) perovskite nanocrystals (NCs), with large two-photon absorption (TPA) cross-section and bright photoluminescence (PL), have been demonstrated as stable two-photon-pumped lasing medium. With two-photon excitation, red-shifted PL spectrum and increased PL lifetime is observed compared with one-photon excitation. We have investigated the origin of such difference using time-resolved laser spectroscopies. We ascribe the difference to the enhanced size selection of NCs by two-photon excitation. Because of inherent nonlinearity, the size dependence of absorption cross-section under TPA is stronger. Consequently, larger size NCs are preferably excited, leading to longer excited-state lifetime and red-shifted PL emission. In a broad view, the enhanced size selection in two-photon excitation of CsPbBr₃ NCs is likely a general feature of the perovskite NCs and can be tuned via NC size distribution to influence their performance within NC-based nonlinear optical materials and devices.

• Author: Junsheng Chen; Pavel Chábera; Torbjörn Pascher; Maria E. Messing; Richard Schaller; Sophie Canton; Kaibo Zheng; Tõnu Pullerits
• Department/s: Chemical Physics; NanoLund: Centre for Nanoscience; Solid State Physics
• Publishing year: 2017-10-19
• Language: English
• Pages: 5119-5124
• Publication/Series: Journal of Physical Chemistry Letters
• Volume: 8
• Issue: 20
• Links: http://dx.doi.org/10.1021/acs.jpclett.7b02178
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Topic: Physical Chemistry (including Surface- and Colloid Chemistry); Condensed Matter Physics (including Material Physics, Nano Physics)
• Status: Published
• ISBN/ISSN/Other: ISSN: 1948-7185