Yang Jia-Jia, Liu Xiang-Yang, Li Zi-Wen, Frauenheim Thomas, Yam ChiYung, Fang Wei-Hai, Cui Ganglong
College of Chemistry, Beijing Normal University, Beijing 100875, China.
Phys Chem Chem Phys. 2021 Mar 21;23(11):6536-6543. doi: 10.1039/d0cp06579j. Epub 2021 Mar 10.
Here, we used collinear and noncollinear density functional theory (DFT) methods to explore the interfacial properties of two heterojunctions between a fullerene (C and C) and the MAPbI(110) surface. Methodologically, consideration of the spin-orbit interaction has been proven to be required to obtain accurate energy-level alignment and interfacial carrier dynamics between fullerenes and perovskites in hybrid perovskite solar cells including heavy atoms (such as Pb atoms). Both heterojunctions are predicted to be the same type-II heterojunction, but the interfacial electron transfer process from MAPbI to C is completely distinct from that to C. In the former, the interfacial electron transfer is slow because of the associated large energy gap, and the excited electrons are thus trapped in MAPbI for a while. In contrast, in the latter, the smaller energy gap induces ultrafast electron transfer from MAPbI to C. These points are further supported by DFT-based nonadiabatic dynamics simulations including the spin-orbit coupling (SOC) effects. These gained insights could help rationally design superior fullerene-perovskite interfaces to achieve high power conversion efficiencies of fullerene-perovskite solar cells.
在此，我们使用共线和非共线密度泛函理论（DFT）方法来探究富勒烯（C 和 C）与 MAPbI(110) 表面之间两种异质结的界面性质。从方法学角度来看，已证明在包括重原子（如 Pb 原子）的混合钙钛矿太阳能电池中，考虑自旋轨道相互作用对于获得富勒烯与钙钛矿之间准确的能级对齐和界面载流子动力学是必要的。预计这两种异质结均为相同类型的 II 型异质结，但从 MAPbI 到 C 的界面电子转移过程与到 C 的过程完全不同。在前者中，由于相关的大能量间隙，界面电子转移缓慢，因此激发电子会在 MAPbI 中被困一段时间。相比之下，在后者中，较小的能量间隙导致从 MAPbI 到 C 的超快电子转移。基于 DFT 的包含自旋轨道耦合（SOC）效应的非绝热动力学模拟进一步支持了这些观点。这些获得的见解有助于合理设计优异的富勒烯 - 钙钛矿界面，以实现富勒烯 - 钙钛矿太阳能电池的高功率转换效率。
