Zhang Xuanyu, Xiao Shuyu, Guo Zhihang, Yuan Baozhen, Wang Xiongbin, Zhang Samo, Shi Yueqing, Xing Guichuan, He Tingchao, Chen Rui
Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
J Phys Chem Lett. 2023 Aug 24;14(33):7581-7590. doi: 10.1021/acs.jpclett.3c01809. Epub 2023 Aug 17.
It is necessary to improve the action cross section (η × σ) of high-order multiphoton absorption (MPA) for fundamental research and practical applications. Herein, the core-shell FAPbBr/CsPbBr nanocrystals (NCs) were constructed, and fluorescence induced by up to five-photon absorption was observed. The value of η × σ reaches 8.64 × 10 cm s photon nm 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.
为了基础研究和实际应用，有必要提高高阶多光子吸收（MPA）的作用截面（η×σ）。在此，构建了核壳结构的FAPbBr/CsPbBr纳米晶体（NCs），并观察到了高达五光子吸收诱导的荧光。在2300 nm处，η×σ的值达到8.64×10 cm s光子nm，这比仅含核心的NCs的值大近一个数量级。研究发现，增加的介电常数促进了MPA效应的调制，通过局部场效应解决了高阶非线性行为中的电子畸变问题。同时，准II型能带排列抑制了双激子俄歇复合，确保了更强的MPA诱导荧光。此外，核壳结构不仅可以降低缺陷密度，还可以通过类天线效应促进非辐射能量转移。这项工作为开发用于未来光子集成的高性能多光子激发纳米材料提供了一条新途径。
