@article{del Águila2020, 
author = {Andrés Granados del Águila and T. Thu Ha Do and Jun Xing and Wen Jie Jee and Jacob B. Khurgin and Qihua Xiong},
title = {Efficient up-conversion photoluminescence in all-inorganic lead halide perovskite nanocrystals},
year = {2020},
journal = {Nano Research},
volume = {13},
number = {7},
pages = {1962-1969},
keywords = {colloidal nanocrystals, lead halide perovskite, up-conversion photoluminescence, phonons},
url = {https://www.sciopen.com/article/10.1007/s12274-020-2840-7},
doi = {10.1007/s12274-020-2840-7},
abstract = {Up-conversion photoluminescence (UCPL) refers to the elementary process where low-energy photons are converted into high-energy ones via consecutive interactions inside a medium. When additional energy is provided by internal thermal energy in the form of lattice vibrations (phonons), the process is called phonon-assisted UCPL. Here, we report the exceptionally large phonon-assisted energy gain of up to ~ 8kBT (kB is Boltzmann constant, T is temperature) on all-inorganic lead halide perovskite semiconductor colloidal nanocrystals that goes beyond the maximum capability of only harvesting optical phonon modes. By systematic optical study in combination with a statistical probability model, we explained the nontrivial phonon-assisted UCPL process in perovskites nanocrystals, where in addition to the strong electron-phonon (light-matter) coupling, other nonlinear processes such as phonon-phonon (matter-matter) interaction also effectively boost the up-conversion efficiency.}
}