Zhou Tingwei, Shao Bin
Chongqing key Laboratory of Micro&Nano Structure Optoelectronics, School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
China Academy of Space Technology (Xi'an), Xi'an, 710110, China.
Phys Chem Chem Phys. 2023 Oct 18;25(40):27409-27416. doi: 10.1039/d3cp03721e.
The direct band gaps of two-dimensional (2D) metal halide perovskites can be tuned component engineering, but their electron transition type hardly changes. Herein, atomically thin (CNH)MX (M = Ge, Sn, Pb; X = Cl, Br, I) hybrid perovskites with hydrophobic superalkali cations were systematically explored using high-throughput hybrid density functional calculations and molecular dynamics simulations. We found that the electron transition between the M and X atoms was converted into that between the CNH parts and X atoms X change in the 2D (CNH)MX perovskites. Negative formation energy, stable thermodynamic and kinetic properties, sharp valence bands, and tunable direct band gaps were obtained for the 2D perovskites. A power conversion efficiency (PCE) of 32.54% was obtained in theory for the passivated cubic NHCHNHPbI (FAPbI) perovskite containing the 2D (CNH)PbI perovskite. The hybrid Pb-free (CNH)SnI perovskite with a direct bandgap of 1.56 eV may be viewed as a potential passivation material for perovskite devices. Moreover, the CNH cations and X atoms show different hydrogen bonding interactions, which can be extended to other atomically thin organic-inorganic hybrid perovskites.
二维（2D）金属卤化物钙钛矿的直接带隙可通过组分工程进行调控，但其电子跃迁类型几乎不变。在此，我们使用高通量混合密度泛函计算和分子动力学模拟，系统地探索了具有疏水超碱阳离子的原子级薄（CNH）MX（M = Ge、Sn、Pb；X = Cl、Br、I）混合钙钛矿。我们发现，在二维（CNH）MX钙钛矿中，随着X的变化，M和X原子之间的电子跃迁转变为CNH部分和X原子之间的电子跃迁。二维钙钛矿具有负形成能、稳定的热力学和动力学性质、尖锐的价带以及可调控的直接带隙。对于含有二维（CNH）PbI钙钛矿的钝化立方NHCHNHPbI（FAPbI）钙钛矿，理论上获得了32.54%的功率转换效率（PCE）。具有1.56 eV直接带隙的无铅混合（CNH）SnI钙钛矿可被视为钙钛矿器件的潜在钝化材料。此外，CNH阳离子和X原子表现出不同的氢键相互作用，这可扩展到其他原子级薄的有机-无机混合钙钛矿。
