Design, structure, and optical properties of organic-inorganic perovskites containing an oligothiophene chromophore
Design, structure, and optical properties of organic-inorganic perovskites containing an oligothiophene chromophore
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DOI：
10.1021/ic991048k
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发表时间：
1999-12-27
影响因子：
4.6
通讯作者：
Kagan, CR
中科院分区：
文献类型：
--
作者：
Mitzi, DB;Chondroudis, K;Kagan, CR
一种四噻吩衍生物，5,5'''-双（氨乙基）-2,2':5',2'':5'',2'''-四噻吩（AEQT），已被选用于嵌入层状有机 - 无机钙钛矿结构中。除了具有合适的分子形状以及两个可与无机骨架键合的连接氨乙基外，AEQT还是一种染料，并且能够影响基于卤化铅（II）的钙钛矿的光学性质。C₂₀H₂₂S₄N₂PbBr₄晶体是从含有溴化铅（II）和四噻吩衍生物（AEQT·2HBr）盐的缓慢冷却的水溶液中生长出来的。这种新的层状钙钛矿采用单斜（C2/c）亚晶胞，其晶格参数为a = 39.741(2)埃，b = 5.8420(3)埃，c = 11.5734(6)埃，β = 92.360(1)度，Z = 4。在X射线衍射数据中观察到宽的超结构峰，这表明沿a轴和b轴存在有序性差的双倍超晶胞。AEQT²⁺的四噻吩部分几乎是平面的，相邻噻吩环之间呈顺 - 反 - 顺关系。每个四噻吩生色团在最近邻的溴化铅（II）层之间呈人字形排列，相对于相邻的四噻吩是有序的。钙钛矿（AEQT）PbX₄（X = Cl，Br，I）的热烧蚀薄膜在室温下的光学吸收光谱显示出来自卤化铅（II）层的激子峰以及来自四噻吩部分的吸收。在任何含生色团的钙钛矿的光致发光光谱中都没有观察到无机层激子跃迁的证据。然而，对于X = Cl，观察到强烈的四噻吩光致发光，其发射峰在大约λ(max) = 532 nm处。对于X = Br和I的材料也观察到类似的光致发光，但有明显的猝灭，因为相对于生色团的最高已占分子轨道 - 最低未占分子轨道间隙，无机层的带隙减小。
A quaterthiophene derivative, 5,5'''-bis(aminoethyl)-2,2':5',2 ":5 ",2'''-quaterthiophene (AEQT), has been selected for incorporation within the layered organic-inorganic perovskite structure. In addition to having an appropriate molecular shape and two tethering aminoethyl groups to bond to the inorganic framework, AEQT is also a dye and can influence the optical properties of lead(II) halide-based perovskites. Crystals of C20H22S4N2PbBr4 were grown from a slowly cooled aqueous solution containing lead(II) bromide and quaterthiophene derivative (AEQT . 2HBr) salts. The new layered perovskite adopts a monoclinic (C2/c) subcell with the lattice parameters a = 39.741(2) Angstrom, b = 5.8420(3) Angstrom, c = 11.5734(6) Angstrom, beta = 92.360(1)degrees, and Z = 4. Broad superstructure peaks are observed in the X-ray diffraction data, indicative of a poorly ordered, doubled supercell along both the a and b axes. The quaterthiophene segment of AEQT(2+) is nearly planar, with a syn-anti-syn relationship between adjacent thiophene rings. Each quaterthiophene chromophore is ordered between nearest-neighbor lead(II) bromide sheets in a herringbone arrangement with respect to neighboring quaterthiophenes. Room temperature optical absorption spectra for thermally ablated films of the perovskites (AEQT)PbX4 (X = CI, Br, I) exhibit an exciton peak arising from the lead(II) halide sheets, along with absorption from the quaterthiophene moiety. No evidence of the inorganic sheet excitonic transition is observed in the photoluminescence spectra for any of the chromophore-containing perovskites. However, strong quaterthiophene photoluminescence is observed for X = Cl, with an emission peak at approximately lambda(max) = 532 nm. Similar photoluminescence is observed For the X = Br and I materials, but with substantial quenching, as the inorganic layer band gap decreases relative to the chromophore HOMO-LUMO gap.