Low‐dimensional hybrid organic‐inorganic metal halides (OIMHs) have attracted considerable attention in anti‐counterfeiting due to their non‐toxicity and high photoluminescence quantum yield (PLQY). However, many reported OIMHs are either not reversible or have a poor PLQY. In this study, two antimony‐based halides, (C21H21P)2SbCl5 and (C22H24P)2SbCl5, are synthesized using different organic cations. Both compounds exhibit bright orange–yellow emissions with a PLQY of 82.6% and 83.5%, respectively. The orange–yellow emission of (C21H21P)2SbCl5 and (C22H24P)2SbCl5 are attributed to the radiative recombination of self‐trapping excitons. While (C21H21P)2SbCl5 maintains stable orange–yellow luminescence when exposed to ethanol, (C22H24P)2SbCl5 undergoes a structural transformation to non‐luminescent (C22H24P)2Sb2Cl8 upon ethanol treatment, which can be reverted to its luminescent state by heating. Even after multiple cycles, the PLQY of (C22H24P)2SbCl5 is still over 80%, demonstrating excellent cycling stability. (C21H21P)2SbCl5 and (C22H24P)2SbCl5 are also explored as fluorescent materials for Morse code anti‐counterfeiting and optical logic gate applications. This work offers a completely new option for fluorescent material used for security information.

中文翻译：

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乙醇诱导的锑卤化物中的可逆相变，用于莫尔斯电码防伪门和光学逻辑门


低维杂化有机-无机金属卤化物 （OIMHs） 因其无毒和高光致发光量子产率 （PLQY） 而在防伪领域引起了相当大的关注。然而，许多报道的 OIMH 要么是不可逆的，要么 PLQY 较差。在这项研究中，使用不同的有机阳离子合成了两种锑基卤化物 （C21H21P）2SbCl5 和 （C22H24P）2SbCl5。两种化合物都表现出明亮的橙黄色发射，PLQY 分别为 82.6% 和 83.5%。（C21H21P）2SbCl5 和 （C22H24P）2SbCl5 的橙黄色发射归因于自捕获激子的辐射复合。虽然 （C21H21P）2SbCl5 在暴露于乙醇时保持稳定的橙黄色发光，但 （C22H24P）2SbCl5 在乙醇处理后发生结构转变为非发光 （C22H24P）2Sb2Cl8，可以通过加热恢复到其发光状态。即使经过多次循环，（C22H24P）2SbCl5 的 PLQY 仍然超过 80%，表现出优异的循环稳定性。（C21H21P）2SbCl5 和 （C22H24P）2SbCl5 也被探索作为莫尔斯电码防伪和光学逻辑门应用的荧光材料。这项工作为用于安全信息的荧光材料提供了一个全新的选择。