Size Dependence of Trion and Biexciton Binding Energies in Lead Halide Perovskite Nanocrystals
Kenichi Cho, Takao Satô, Takumi Yamada, Ryota Sato, Masaki Saruyama, Toshiharu Teranishi, Hidekatsu Suzuura, Yoshihiko Kanemitsu
Abstract
Lead halide perovskite nanocrystals (NCs) have attracted much attention as light-source materials for light-emitting diodes, lasers, and quantum light emitters. The luminescence properties of perovskite NCs and the performance of NC-based light-source devices depend on trion and biexciton dynamics. Here, we examined the size dependence of trion and biexciton binding energies by conducting low-temperature single-dot spectroscopy on three different perovskite NCs: CsPbBr 3, CsPbI 3, and FAPbBr 3 . While the photoluminescence spectral widths of the all-inorganic CsPbBr 3 and CsPbI 3 NCs were narrow, compared with those of the organic–inorganic hybrid FAPbBr 3 NCs, the binding energies of trions and biexcitons of all three samples showed similar size dependences, independent of the A-site cation and halogen. The effective-mass approximation calculations implied the importance of dynamical dielectric screening on the formation of trions and biexcitons.