Syzgantseva Olga A, Saliba Michael, Grätzel Michael, Rothlisberger Ursula
Laboratory of Computational Chemistry and Biochemistry and ‡Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland.
J Phys Chem Lett. 2017 Mar 16;8(6):1191-1196. doi: 10.1021/acs.jpclett.6b03014. Epub 2017 Feb 28.
In this work we perform a computational study comparing the influence of monovalent cation substitution by methylammonium (MA), cesium (Cs), and rubidium (Rb) on the properties of formamidinium lead triiodide (FAPbI)-based perovskites. The relative stability of the desired, photoactive perovskite α phase ("black phase") and the nonphotoactive, nonperovskite δ phase ("yellow phase") is studied as a function of dopant nature, concentration and temperature. Cs and Rb are shown to be more efficient in the stabilization of the perovskite α phase than MA. Furthermore, varying the dopant concentration allows changing the relative stability at different temperatures, in particular stabilizing the α phase already at 200 K. Upon Cs or Rb doping, the corresponding onset of the optical spectrum is blue-shifted by 0.1-0.2 eV with respect to pure FAPbI.
在这项工作中，我们进行了一项计算研究，比较了用甲铵（MA）、铯（Cs）和铷（Rb）取代一价阳离子对基于甲脒铅三碘化物（FAPbI）的钙钛矿性质的影响。研究了所需的光活性钙钛矿α相（“黑色相”）和非光活性、非钙钛矿δ相（“黄色相”）的相对稳定性与掺杂剂性质、浓度和温度的关系。结果表明，Cs和Rb在稳定钙钛矿α相方面比MA更有效。此外，改变掺杂剂浓度可以改变不同温度下的相对稳定性，特别是在200K时就可以稳定α相。在Cs或Rb掺杂后，相对于纯FAPbI，相应的光谱起始点发生了0.1-0.2 eV的蓝移。
