Ma Linlin, Zhou Chenyang, Zhang Haoyue, Sun Yan, Wang Beibei, Feng Xia, Chu Ya, Wu Zibo, Wang Chao, Zhao Guangjiu
Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical Engineering Education, School of Science, Tianjin University, Tianjin 300354, China.
Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical Engineering Education, School of Science, Tianjin University, Tianjin 300354, China.
J Colloid Interface Sci. 2021 Apr 15;588:494-500. doi: 10.1016/j.jcis.2020.12.094. Epub 2020 Dec 28.
In this work, we report a family of co-halogenated two-dimensional hybrid perovskites (2DHPs) based on phenethylammonium lead halogen ((PEA)Pb(Cl/Br)) in which the organic cation-site (PEA) is substituted with halogen at the para-site, namely the formation of 4-halophenethylamine (X-p-PEA) (X = Cl, Br; p: para-site). The organic cations are regulated by introducing halogen ions at the para-site of the benzene ring to promote the structural distortion of the lead halide octahedral inorganic layer. Furthermore, (X-p-PEA) causes a shift in the energy band distribution of 2DHPs. In this case, the photoluminescence competition of free excitons (FEs) and self-trapped excitons (STEs) changes the microscopic relaxation process of excitons. In addition, we found that (Br-p-PEA) can increase the photoluminescence quantum yield (PLQY). At the same time, we regulate the halogen-site of perovskites from lead-chloride perovskites (LCPs) to lead bromine perovskites (LBPs), achieving emission from white light to blue light. Therefore, the co-halogenation regulation strategy of organic cation-site and halogen-site can effectively regulate the photoluminescence wavelength and improve the PLQY. This is of great significance for the development of perovskite materials with specific optoelectronic applications.
在本工作中，我们报道了一族基于苯乙铵铅卤化物（(PEA)Pb(Cl/Br)）的共卤化二维杂化钙钛矿（2DHPs），其中有机阳离子位点（PEA）在对位被卤素取代，即形成了4-卤代苯乙胺（X-p-PEA）（X = Cl、Br；p：对位）。通过在苯环的对位引入卤素离子来调控有机阳离子，以促进卤化铅八面体无机层的结构畸变。此外，（X-p-PEA）导致2DHPs的能带分布发生偏移。在这种情况下，自由激子（FEs）和自陷激子（STEs）的光致发光竞争改变了激子的微观弛豫过程。另外，我们发现（Br-p-PEA）可以提高光致发光量子产率（PLQY）。同时，我们将钙钛矿的卤素位点从氯化铅钙钛矿（LCPs）调控到溴化铅钙钛矿（LBPs），实现了从白光到蓝光的发射。因此，有机阳离子位点和卤素位点的共卤化调控策略可以有效调控光致发光波长并提高PLQY。这对于开发具有特定光电子应用的钙钛矿材料具有重要意义。
