Fig. 7
From: Hybrid perovskite light emitting diodes under intense electrical excitation
Evidence of charge imbalance. Electroluminescence spectra at high current density, demonstrating blue poly-TPD emission due to electron leakage out of the perovskite emissive layer as shown in the inset. Emission at wavelengths below 410 nm is cut off due to the use of a long-pass filter and the photoluminescence spectrum of poly-TPD (blue line) is overlaid for comparison
