Effective Phase Control for High-Performance Red-Light-Emitting Quasi-2D Perovskite Solar Cells via MACl Additive

Quasi-2D Ruddlesden–Popper (RP) perovskite films have been widely used in fabricating high-performance perovskite light-emitting diodes (PeLEDs) and solar cells because of their environmental stability and specific optoelectronic properties. However, it is rarely reported that dual-functional light-emitting quasi-2D perovskite solar cells can be obtained with excellent performance. Herein, we demonstrated the effectiveness of MACl for modulating the phase distribution and crystal orientation. By adjusting the MACl concentration, the optimized perovskite PEA2MA2Pb3I10–xClx films show increased phase purity and mixed crystalline orientation consisting of in-plane and out-plane orientations. Then we demonstrated that the optimal perovskite films could realize dual-functional application with a device structure of ITO (Glass)/PEDOT:PSS/Perovskite/PCBM/PEI/Ag. When functioning as a solar cell, the optimal device shows an open voltage (Voc) of 1.183 V and a power conversion efficiency (PCE) of 8.64%. When functioning as a LED, the optimal device exhibits a red emission at 645 nm with a maximum luminance (Lmax) of 1598 cd/m2 and an external quantum efficiency (EQE) of 2.2%. Our work investigates the effect of MACl on phase control toward narrow distribution and crystal orientation modulation and then demonstrates that an enhanced performance quasi-2D perovskite light-emitting solar cell can be realized with both improved charge transport and effective radiative recombination.