Improving the Five-Photon Absorption from Core–Shell Perovskite Nanocrystals
Xuanyu Zhang, Shuyu Xiao, Zhihang Guo, Baozhen Yuan, Xiongbin Wang, Samo Zhang, Yueqing Shi, Guichuan Xing, Tingchao He, Rui Chen
Abstract
It is necessary to improve the action cross section (η × σ n ) of high-order multiphoton absorption (MPA) for fundamental research and practical applications. Herein, the core–shell FAPbBr 3 /CsPbBr 3 nanocrystals (NCs) were constructed, and fluorescence induced by up to five-photon absorption was observed. The value of η × σ 5 reaches 8.64 × 10 –139 cm 10 s 4 photon –4 nm –3 at 2300 nm, which is nearly an order of magnitude bigger than that of the core-only NCs. It is found that the increased dielectric constant promotes modulation of MPA effects, addressing the electronic distortion in high-order nonlinear behaviors through the local field effect. Meanwhile, the quasi-type-II band alignment suppresses the biexciton Auger recombination, ensuring the stronger MPA induced fluorescence. In addition, the core–shell structure can not only reduce the defect density but also promote the nonradiative energy transfer though the antenna-like effect. This work provides a new avenue for the exploitation of high-performance multiphoton excited nanomaterials for future photonic integration.