High-Performance Pure Red Quasi-Two-Dimensional Perovskite Light-Emitting Diodes with Bifunctional Potassium Trifluoroacetate Additive

Solution-processed pure iodide-based quasi-two-dimensional (quasi-2D) perovskites exhibit tremendous potential for pure red light-emitting diodes, required for a wide color gamut display. However, the nonradiative recombination derived from the numerous defects and broad phase distribution restricts the performance of quasi-2D perovskite light-emitting diodes (PeLEDs). Herein, we demonstrate high-performance pure red quasi-2D PeLEDs by introducing a bifunctional potassium trifluoroacetate (KTFA) additive that simultaneously passivates the defects and regulates phase distribution. The KTFA-modified PeLEDs achieve a peak external quantum efficiency of 18.70%, a maximum luminance of 2377.1 cd m^–2, and an electroluminescence (EL) emission peak at 650 nm with a CIE coordinate of (0.705,0.295) approaching the pure red emission of Rec.2020 standard. Moreover, our devices demonstrate a stable EL spectrum and a half-lifetime (T₅₀) of 476 min at an initial luminance of 100 cd m^–2. Our work provides a viable strategy to boost the performance of quasi-2D PeLEDs.