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Bismuth Doping Alters Structural Phase Transitions in Methylammonium Lead Tribromide Single Crystals
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2021-03-11 , DOI: 10.1021/acs.jpclett.1c00334
Erin Jedlicka 1 , Jian Wang 1 , Joshua Mutch 2 , Young-Kwang Jung 3 , Preston Went 2 , Joseph Mohammed 1 , Mark Ziffer 1 , Rajiv Giridharagopal 1 , Aron Walsh 3, 4 , Jiun-Haw Chu 2 , David S. Ginger 1
Affiliation  

We study the effects of bismuth doping on the crystal structure and phase transitions in single crystals of the perovskite semiconductor methylammonium lead tribromide, MAPbBr3. By measuring the temperature-dependent specific heat capacity (Cp), we find that as the Bi doping increases, the phase transition assigned to the cubic to tetragonal phase boundary decreases in temperature. Furthermore, after doping we observe one phase transition between 135 and 155 K, in contrast to two transitions observed in the undoped single crystal. These results appear strikingly similar to previously reported effects of mechanical pressure on perovskite crystal structure. Using X-ray diffraction, we show that the lattice constant decreases as Bi is incorporated into the crystal, as predicted by density functional theory. We propose that bismuth substitutional doping on the lead site is dominant, resulting in BiPb+ centers that induce compressive chemical strain that alters the crystalline phase transitions.

中文翻译:

铋掺杂改变甲基铵三溴化铅单晶中的结构相变

我们研究了铋掺杂对钙钛矿半导体甲基铵三溴化铅MAPbBr 3的单晶体的晶体结构和相变的影响。通过测量温度相关的比热容(C p),我们发现随着Bi掺杂的增加,分配给立方相至四方相边界的相变温度降低。此外,与未掺杂的单晶中观察到的两个跃迁相反,在掺杂之后,我们观察到在135 K和155 K之间的一个相变。这些结果与以前报道的机械压力对钙钛矿晶体结构的影响惊人地相似。使用X射线衍射,我们发现,随着Bi被掺入晶体中,晶格常数会降低,这是由密度泛函理论预测的。我们提出,铅位点上的铋取代掺杂占主导地位,导致Bi Pb +中心诱导了压缩化学应变,从而改变了晶体的相变。
更新日期:2021-03-25
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