论文标题
sn/ge替换为（（c $ _ \ textrm {n} $ h $ _ {2 \ textrm {n} -1} $ nh $ _3 $）$ _ 2 $ _ 2 $ _4 $ _4 $; n = 3）
Sn/Ge substitution in ((C$_\textrm{n}$H$_{2\textrm{n}-1}$NH$_3$)$_2$PbI$_4$; n=3): An emerging 2D layered hybrid perovskites with enhanced optoelectronic properties$^†$
论文作者
论文摘要
与三维（3D）对应物相比，二维（2D）钙钛矿显示出更高的稳定性。因此，2D钙钛矿在对其物理特性和光电应用的基本理解中引起了极大的关注。在这里，我们提出了基于基于原始环状铵基于原始环状氨基的无机无机（IO）混合系统的低维自然化（C $ _ {\ textrm {n}} $ H $ _ {2 \ textrm {\ textrm {n}} $ _ {2 \ textrm {n} n} -1} -1} -1} -1} -1} $ nh $ nh $ _ {3} $ {3} $） （（c $ _ {\ textrm {n}} $ h $ _ {2 \ textrm {n} -1} $ nh $ _3 $）$ _ 2 $ _ 2 $ PBI $ _4 $ _4 $; n = 3-6）]。但是，铅（PB）引起的巨大带隙性质和毒性的存在禁止其应用。因此，在目前的工作中，我们研究了GE/SN替代和PB散布（Pb-$ \ boxtimes $）的作用，以降低PB的浓度并通过形成混合的钙钛矿结构来提高太阳能细胞效率。我们已经使用最先进的杂化密度功能理论（DFT）讨论了自旋轨道耦合（SOC）的效果。我们发现具有PB-$ \ boxtimes $的混合构象异构体不具有结构性稳定性。此外，它们具有间接的带隙，这对太阳能电池应用不利。只有那些具有良好热力学和结构稳定性的构象体才能进一步研究光学性质。我们的结果推断，SN替换比GE取代PB并提高效率更有利。使用Wannier-mott方法计算出的原始和取代构象异构体的激子结合能大于铅卤化物钙钛矿，而电子偶联的前者中的电子偶联较小。从计算的光谱有限的最大效率（SLME）中，这些2D钙钛矿作为常规铅卤化物钙钛矿的替代方案表现出足够的希望。
Two-dimensional (2D) perovskites show higher stability in comparison to their three-dimensional (3D) counterparts. Therefore, 2D perovskites have invoked remarkable attention in basic understanding of their physical properties and optoelectronic applications. Here we present a low-dimensional naturally self-assembled inorganic-organic (IO) hybrid systems based on primary cyclic ammonium-based (C$_{\textrm{n}}$H$_{2\textrm{n}-1}$NH$_{3}$) semiconductor series [viz. ((C$_{\textrm{n}}$H$_{2\textrm{n}-1}$ NH$_3$)$_2$PbI$_4$; n=3-6)]. However, the wide bandgap nature and presence of toxicity due to lead (Pb) prohibit their applications. Therefore, in the present work, we study the role of Ge/Sn substitution and Pb-vacancy (Pb-$\boxtimes$) to reduce concentration of Pb and to enhance solar cell efficiency by the formation of mixed perovskite structures. We have discussed the effect of spin-orbit coupling (SOC) using state-of-the-art hybrid density functional theory (DFT). We find the mixed conformers with Pb-$\boxtimes$ do not possess structural stability. Moreover, they have indirect bandgap, which is not good for solar cell applications. Only those conformers, which have favourable thermodynamics and structural stability, are considered for further study of optical properties. Our results infer that Sn substitution is more favorable than that of Ge in replacing Pb and enhancing the efficiency. Exciton binding energies calculated using Wannier-Mott approach for pristine and substituted conformers are larger than lead halide perovskites, while the electron-phonon coupling is smaller in the former. From computed spectroscopic limited maximum efficiency (SLME), these 2D perovskites show enough promise as alternatives to conventional lead halide perovskites.
