Size-And Wavelength-Dependent Two-Photon Absorption Cross-Section of CsPbBr₃ Perovskite Quantum Dots

Summary, in English

All-inorganic colloidal perovskite quantum dots (QDs) based on cesium, lead, and halide have recently emerged as promising light emitting materials. CsPbBr₃ QDs have also been demonstrated as stable two-photon-pumped lasing medium. However, the reported two photon absorption (TPA) cross sections for these QDs differ by an order of magnitude. Here we present an in-depth study of the TPA properties of CsPbBr₃ QDs with mean size ranging from 4.6 to 11.4 nm. By using femtosecond transient absorption (TA) spectroscopy we found that TPA cross section is proportional to the linear one photon absorption. The TPA cross section follows a power law dependence on QDs size with exponent 3.3 ± 0.2. The empirically obtained power-law dependence suggests that the TPA process through a virtual state populates exciton band states. The revealed power-law dependence and the understanding of TPA process are important for developing high performance nonlinear optical devices based on CsPbBr₃ nanocrystals.

• Author: Junsheng Chen; Karel Zidek; Pavel Chábera; Dongzhou Liu; Pengfei Cheng; Lauri Nuuttila; Mohammed J. Al-Marri; Heli Lehtivuori; Maria E. Messing; Keli Han; Kaibo Zheng; Tõnu Pullerits
• Department/s: Chemical Physics; NanoLund: Centre for Nanoscience; Solid State Physics
• Publishing year: 2017-05-18
• Language: English
• Pages: 2316-2321
• Publication/Series: Journal of Physical Chemistry Letters
• Volume: 8
• Issue: 10
• Links: http://dx.doi.org/10.1021/acs.jpclett.7b00613
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Topic: Condensed Matter Physics (including Material Physics, Nano Physics)
• Status: Published
• ISBN/ISSN/Other: ISSN: 1948-7185