Institute of Optoelectronic Materials and Devices, China Jiliang University, Hangzhou 310018, P. R. China.
School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
Nano Lett. 2021 Dec 22;21(24):10222-10229. doi: 10.1021/acs.nanolett.1c03134. Epub 2021 Nov 30.
Achieving bright photon upconversion under low irradiance is of great significance and finds many stimulating applications from photovoltaics to biophotonics. However, it remains a daunting challenge to significantly intensify upconversion luminescence in small nanoparticles with a simple structure. Herein, we report the amplification of photon upconversion through engineering interfacial density of states between the core and the shell layer in sub-10 nm colloidal rare-earth ions doped fluoride nanocrystals. Through tuning of the metal cations in the shell layer of alkaline-earth-based core/shell nanoparticles, both the interfacial phonon frequency and the density of state are evidently decreased, resulting in the luminescence intensification of up to 8224 times. The generality of this upconversion enhancement strategy has been verified through expansion of this approach to alkali-based core/shell nanoparticles. The engineering of photon density of state in such core/shell nanoparticles enables dynamic display and high-level security information storage.
在低辐照度下实现明亮的上转换光子是非常重要的，它在从光伏到生物光子学的许多领域都有令人兴奋的应用。然而，用简单的结构在纳米颗粒中显著增强上转换发光仍然是一个艰巨的挑战。在此，我们通过在亚 10nm 胶体稀土离子掺杂氟化物纳米晶中工程化核壳层之间的态密度，报告了光子上转换的放大。通过调节碱土基核/壳纳米粒子壳层中的金属阳离子，界面声子频率和态密度明显降低，导致上转换发光强度增强高达 8224 倍。通过将这种方法扩展到基于碱的核/壳纳米粒子，验证了这种上转换增强策略的通用性。在这种核壳纳米粒子中对光子态密度的工程设计能够实现动态显示和高级别的安全信息存储。
