Filip Marina R, Qiu Diana Y, Del Ben Mauro, Neaton Jeffrey B
Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom.
School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States.
Nano Lett. 2022 Jun 22;22(12):4870-4878. doi: 10.1021/acs.nanolett.2c01306. Epub 2022 Jun 9.
Interlayer organic cations in quasi-two-dimensional halide perovskites are a versatile tuning vehicle for the optoelectronic properties of these complex systems, but chemical intuition for this design route is yet to be established. Here, we use density functional theory, the approximation, and the Bethe-Salpeter equation approach to understand the contribution of the organic cation to the quasiparticle band gap and exciton binding energy of layered perovskites. We show that organic cations in quasi-two-dimensional perovskites contribute significantly to the dielectric screening in these systems, countering quantum confinement effects on the quasiparticle band gap and the exciton binding energy. Using a simple electrostatics model inspired by parallel-plate capacitors, we decouple the organic cation and inorganic layer contributions to the effective dielectric constants and show that dielectric properties of layered perovskites are broadly tunable via the interlayer cation, providing a direct means of tuning photophysical properties for a variety of applications.
准二维卤化物钙钛矿中的层间有机阳离子是调节这些复杂体系光电性质的通用工具，但这种设计途径的化学原理尚未确立。在此，我们使用密度泛函理论、 近似方法以及贝叶斯 - 萨尔皮特方程方法来理解有机阳离子对层状钙钛矿的准粒子带隙和激子结合能的贡献。我们表明，准二维钙钛矿中的有机阳离子对这些体系中的介电屏蔽有显著贡献，抵消了量子限制对准粒子带隙和激子结合能的影响。通过一个受平行板电容器启发的简单静电模型，我们将有机阳离子和无机层对有效介电常数的贡献解耦，并表明层状钙钛矿的介电性质可通过层间阳离子广泛调节，为各种应用提供了一种直接调节光物理性质的方法。
