The synthesis, crystal structure and room‐temperature phosphorescence (RTP) of a 2D metal‐free inorganic covalent framework ((H2en) [B5O8(OH)], named as CityU‐12, and en represents for ethylenediamine) are reported. The precise structure information of CityU‐12 has been disclosed through both single‐crystal X‐ray diffraction (SCXRD) analysis and low‐dose high‐resolution transmission electron microscopy (LD‐HRTEM) study. The SCXRD results show that CityU‐12 composes of 2D anionic B─O‐based covalent inorganic frameworks with protonated ethylenediamine locating in the pore sites of 2D B─O layers while LD‐HRTEM suggests that CityU‐12 has an interplanar distance of 0.60 nm for (00) crystal plane and 0.60 nm for (10) crystal plane. The optical studies show that CityU‐12 is an excellent nonconventional RTP material with the emission peak at 530 nm and a lifetime of 1.5 s. The quantum yield is 84.6% and the afterglow time is as long as 2.5 s. This work demonstrates that metal‐free B─O frameworks can be promising nonconventional phosphors for RTP.

中文翻译：

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二维无金属无机共价框架：合成、晶体结构和室温磷光


报道了二维无金属无机共价骨架（(H2en)[B5O8(OH)]，命名为CityU-12，en代表乙二胺）的合成、晶体结构和室温磷光（RTP）。 CityU-12 的精确结构信息已通过单晶 X 射线衍射 (SCXRD) 分析和低剂量高分辨率透射电子显微镜 (LD-HRTEM) 研究公开。 SCXRD 结果表明，CityU-12 由二维阴离子 B─O 基共价无机骨架组成，质子化乙二胺位于二维 B─O 层的孔位中，而 LD-HRTEM 表明 CityU-12 的面间距为 0.60 nm (00) 晶面为 0.60 nm，(10) 晶面为 0.60 nm。光学研究表明，CityU-12是一种优异的非常规RTP材料，发射峰位于530 nm，寿命为1.5 s。量子产率为84.6%，余辉时间长达2.5 s。这项工作表明，无金属 B─O 框架可以成为很有前途的 RTP 非常规荧光粉。