Recently, lead halide perovskites have attracted great interest in toxic gas detection, but as gas sensor, it is still a challenge to achieve their high-performance. Here, we propose a novel “turn-on” fluorescence NH₃/amine vapor sensor by depositing the CH₃NH₃PbBr₃ (MAPbBr₃) on the mesoporous TiO₂ (mp-TiO₂) layer. The fluorescence intensity of the sensor increases rapidly within seconds upon exposure to NH₃ gas (72 % at 5 ppm and 988 % at 100 ppm, respectively) with excellent reversibility, high gas selectivity, humidity insensitivity, and regeneration. Moreover, the sensor can be further used for detecting various amine vapors, including methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, and decylamine. We presumed the “turn-on” fluorescence sensing mechanism is that the trace NH₃ or amine molecules could decrease the surface trap defects and facilitate the formation of passivation layer. It will impede the electron-injection into mp-TiO₂, which induces the radiative electron-hole recombination and fluorescence enhancement. This research demonstrates that it is feasible to design a “turn-on” fluorescence gas sensor based on the mp-TiO₂-based perovskite.

最近，卤化钙钛矿对有毒气体检测引起了极大的兴趣，但是作为气体传感器，实现其高性能仍然是一个挑战。在这里，我们通过在中孔TiO ₂（mp-TiO ₂）层上沉积CH ₃ NH ₃ PbBr ₃（MAPbBr ₃）提出了一种新颖的“开启”荧光NH ₃ /胺蒸气传感器。暴露于NH ₃后，传感器的荧光强度在数秒内迅速增加气体（5 ppm时为72％，100 ppm时为988％），具有优异的可逆性，高气体选择性，湿度不敏感性和再生能力。此外，该传感器可以进一步用于检测各种胺蒸气，包括甲胺，乙胺，丙胺，丁胺，己胺，辛胺和癸胺。我们认为“开启”荧光传感机制是微量的NH ₃或胺分子可以减少表面陷阱缺陷并促进钝化层的形成。这将阻止电子注入mp-TiO ₂，从而引起辐射电子-空穴复合和荧光增强。这项研究表明，基于mp-TiO ₂设计“开启”荧光气体传感器是可行的钙钛矿。