Efficient Room-Temperature Phosphorescence in 2D Perovskite via Mixed Organic Cation Incorporation.

The achievement of RTP in hybrid organic-inorganic perovskites (HIOPs) via molecular engineering remains relatively uncommon. Here, a series of novel 2D HIOPs composed of mixed organic cations such as naphthalene methylamine (NMA) and 2-(4-methylphenyl) ethanamine (4MPEA) are reported. Efficient RTP and tunable emissions ranging from green to yellow to orange, depending on the doping ratio, are activated in the organic cation-mixed 2D HIOPs system. It has been certified that the triplet excitons of NMA primarily stem from the Wannier excitons of the inorganic layer through an energy transfer process. By gradually altering the halide composition from Br to Cl, the NMA substituted chlorine-based 2D HIOPs show an outstandingly long lifetime of 176 ms. Moreover, potential applications in multiple information encryption and displays have been demonstrated. Our study confirms the effectiveness of strategically hybridizing organic cations with inorganic matrices at the molecular level to achieve high performance RTP.