Highly luminescent and stable layered perovskite as the emitter for light emitting diodes

Article abstract of DOI:10.1002/pssa.201600246

Air instability and poor exciton recombination of 3D perovskites MAPbX₃ (MA = CH₃NH₃, X = halogens) seriously hinder their applications in light emitting diodes. Herein, we report a promising alternative to solve these two critical drawbacks. Layered perovskite OA₂(MA)_n?1Pb_nBr_3n+1 (OA = C₈H₁₇NH₃) has higher binding energy and is passivated by long organic chain, which can be synthesized using a facile method. By increasing the OA⁺ ratio in layered perovskite, strong quantum confinement effect and obvious features of exciton were observed in photoluminescence and UV-Vis absorption spectra. Notably, the photoluminescence quantum yield (PLQY) of (OA)₂(MA)₂Pb₃Br₁₀ (n = 3 layered perovskite) can be up to 67.3% due to the enhanced exciton recombination, significantly higher than its 3D counterpart. Moreover, layered perovskite exhibits promoted stability in air than that of the 3D perovskite. The layered perovskite (OA)₂(MA)₂Pb₃Br₁₀-based perovskite light emitting diodes (PeLEDs) with a maximum current efficiency, a maximum power efficiency and the external quantum efficiency (EQE) of 1.43 cd A^?1, 0.89 lm W^?1, and 0.53% was demonstrated, which can be compared with that of the best-reported perovskite quantum dots LEDs so far. The demonstration of layered perovskite renders its bright future in optoelectronic applications, such as displays and photodetections.