Ultralong room temperature phosphorescence (URTP) is an attractive phenomenon in organic photonics. Polymer‐based URTP materials are superior alternatives to traditional inorganic or organometallic phosphors because of their unique transparency and flexibility. However, few URTP polymer films achieve room temperature phosphorescence lifetimes longer than 2 s and the polymer films with longer lifetimes show extremely low phosphorescence quantum yields (<2%). Herein, a reasonable strategy is proposed to simultaneously achieve ultralong room temperature phosphorescence lifetimes and high phosphorescence quantum yields in polymer films, based on the effective suppression of nonradiative decay of organic phosphors by dense 3D network. A record‐breaking 2.28 s ultralong phosphorescence lifetime and up to 8.35% phosphorescence quantum yield are realized simultaneously in the tetramethylbenzidine (TMB)‐doped URTP polymer film fabricated by a simple doping method. The URTP can be excited by ultralow power UV light (5 µW cm⁻²) or only sunlight, which demonstrates the superb practicality of the polymer network films. In addition, it is noted that the film can still emit phosphorescence lasting 3 s at a temperature as high as 60 °C. A double encryption system is successfully developed based on the unique features of the URTP films.

中文翻译：

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3D网络增强的有机磷掺杂聚合物薄膜的超长和高效室温磷光

超长室温磷光（URTP）是有机光子学中的一种有吸引力的现象。基于聚合物的URTP材料具有独特的透明性和灵活性，是传统无机或有机金属磷光体的优良替代品。但是，很少有URTP聚合物薄膜具有比2 s更长的室温磷光寿命，并且具有更长寿命的聚合物薄膜显示出极低的磷光量子产率（<2％）。本文中，基于通过密集的3D网络有效抑制有机磷光体的非辐射衰变，提出了一种合理的策略，可同时在聚合物薄膜中实现超长的室温磷光寿命和高磷光量子产率。创纪录的2.28 s超长磷光寿命，长达8个。通过简单的掺杂方法制备的掺有四甲基联苯胺（TMB）的URTP聚合物薄膜可同时实现35％的磷光量子产率。URTP可以被超低功率紫外线（5 µW cm^-2）或仅阳光照射，这证明了聚合物网络薄膜的卓越实用性。另外，应当指出，该膜在高达60℃的温度下仍可以发出持续3秒的磷光。基于URTP电影的独特功能，成功开发了双重加密系统。