Highly bright and stable single-crystal perovskite light-emitting diodes

Metal-halide perovskite light-emitting diodes (PeLEDs) have attracted great interest because of their tunable emission wavelength, narrow emission bandwidth and high external quantum efficiency. However, PeLEDs face two critical issues that limit their potential applications: short device lifetime due to ion migration and low brightness due to severe Auger recombination. Here we demonstrate that both issues can be mitigated by in situ solution-grown perovskite single crystals (SCs). By minimizing the trap density using mixed cations and adding excess ammonium halides and polyvidone to the precursor, the external photoluminescence quantum yield (PLQY) of the SCs is enhanced to 28.3%, corresponding to an internal PLQY of 89.4%. Benefitting from the suppressed Auger recombination in SCs, SC-PeLEDs with a thickness of 1.5 mu m exhibit a high luminance of 86,000 cd m(-2) and a peak external quantum efficiency of 11.2%. Thanks to suppressed ion migration, the extrapolated T-50 lifetime for SC-PeLEDs reaches a value of 12,500 h at an initial luminance of 100 cd m(-2). Our results show that SC growth represents a viable route to increase the lifetime of PeLEDs for practical applications. Single-crystal perovskite LEDs exhibit reduced ion migration and Auger recombination and increased device lifetime. Perovskite single-crystals-based LEDs exhibit a maximum brightness of 86,000 cd m(-2), a peak EQE of 11.2% and T-50 lifetime of 12,500 h at an initial luminance of 100 cd m(-2).

Automated summary

By minimizing the trap density using mixed cations and excess ammonium halides and polyvidone as precursors, the use of in situ solution-grown perovskite single crystals (SCs) can mitigate ion migration and severe Auger recombination, resulting in increased device lifetime and brightness.