We present a structural and optoelectronic study of 1D piperidinium, pyridinium, and 3-hydroxypyridinium lead trihalides. In contrast to the piperidinium and pyridinium species whose single inorganic chains [PbX₃¹⁻]_n are separated by organic cations, the 3-hydroxypyridinium compound is characterized by double inorganic chains. According to DFT the valence and conduction bands of the piperidinium lead trihalides are composed of occupied p-orbitals of the halogen anions and unoccupied p-orbitals of the Pb²⁺ cations. In contrast, the pyridinium species feature low-lying cationic energy levels formed from the cation's π*-orbitals. Thus, electronic transitions between the cationic energy levels and valence bands require less energy than valence to conduction band transitions in the case of piperidinium lead trihalides. The presence of an OH group in the pyridinium ring leads to a bathochromic shift of the cationic energy levels resulting in a decreased energy of transitions from the cationic energy levels to the valence band. Electronic transitions predicted by DFT are observable in experimental optical absorption and luminescence spectra. This study paves the way for creation of 1D perovskite-like structures with desired optoelectronic properties.

中文翻译：

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有机阳离子对一维哌啶鎓，吡啶鎓和3-羟基吡啶鎓三卤化铅的电子，光学和发光性质的影响

我们目前对一维哌啶，吡啶鎓和3-羟基吡啶三卤化铅的结构和光电研究进行了研究。与单一的无机链[PbX ₃ ^1- ] _n被有机阳离子隔开的哌啶鎓和吡啶鎓类相比，3-羟基吡啶鎓化合物的特征在于具有双无机链。根据DFT，哌啶鎓三卤化铅的价态和导带由卤素阴离子的占据的p-轨道和Pb ^2+的未占据的p-轨道组成阳离子。相反，吡啶鎓类的特征是由阳离子的π*轨道形成的低位阳离子能级。因此，在三卤化铅铅的情况下，阳离子能级和价带之间的电子跃迁所需的能量少于价带到导带跃迁的价。吡啶鎓环中OH基的存在导致阳离子能级的红移，导致从阳离子能级到价带的跃迁能降低。DFT预测的电子跃迁在实验的光吸收和发光光谱中可见。这项研究为创建具有所需光电特性的一维钙钛矿状结构铺平了道路。