Li Deyang, Chen Guanying
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering & Key Laboratory of Micro-systems and Micro-structures, Ministry of Education, Harbin Institute of Technology, Harbin 150001, People's Republic of China.
J Phys Chem Lett. 2023 Mar 23;14(11):2837-2844. doi: 10.1021/acs.jpclett.3c00382. Epub 2023 Mar 13.
Near-infrared (NIR) luminescent phosphors hold promise for a wide range of applications, from bioimaging to light-emitting diodes (LEDs), but are typically confined to wavelengths <1300 nm and manifest substantial thermal quenching pervasive in luminescent materials. Here we observed the thermally enhanced NIR luminescence of Er (1540 nm), a 2.5-fold enhancement with increasing temperature from 298 to 356 K, from Yb- and Er-codoped CsPbCl perovskite quantum dots (PQDs) (photoexcited at ∼365 nm). Mechanistic investigations revealed that thermally enhanced phenomena originated from combined effects of thermally stable cascade energy transfer (from a photoexcited exciton to a pair of Yb and then to surrounding Er) and minimized quenching of surface-adsorbed water molecules on the I state of Er induced by the temperature increase. Importantly, these PQDs enable producing phosphor-converted LEDs emitting at 1540 nm with inherited thermally enhanced properties, having implications for a wide range of photonic applications.
近红外（NIR）发光磷光体在从生物成像到发光二极管（LED）等广泛的应用中具有前景，但通常限于波长<1300 nm，并且在发光材料中普遍存在显著的热猝灭现象。在此，我们观察到在Yb和Er共掺杂的CsPbCl钙钛矿量子点（PQD）（在~365 nm光激发）中，Er（1540 nm）的近红外发光随温度升高而增强，从298 K到356 K温度升高时增强了2.5倍。机理研究表明，热增强现象源于热稳定的级联能量转移（从光激发的激子到一对Yb，然后到周围的Er）以及温度升高导致表面吸附水分子对Er的I态猝灭最小化的综合作用。重要的是，这些PQD能够制造出在1540 nm发射且具有继承的热增强特性的磷光转换LED，对广泛的光子应用具有重要意义。
