Abstract
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.
| Original language | English |
|---|---|
| Pages (from-to) | 2316-2321 |
| Number of pages | 6 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 8 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 18 May 2017 |
| Externally published | Yes |
| Publication type | A1 Journal article-refereed |
Funding
This work was financed by the Swedish Research Council (VR) the Knut and Alice Wallenberg Foundation, and NPRP Grant # NPRP7-227-1-034 from the Qatar National Research Fund, Interreg Oresund-Kattegat-Skagerrak European regional development fund, and the Program of Study Abroad for Young Teachers by the Agricultural University of Hebei. Keli Han thanks the support from the National Natural Science Foundation of China (Grant No: 21533010).
ASJC Scopus subject areas
- General Materials Science
- Physical and Theoretical Chemistry