Tiny flaws in blue perovskite LEDs tank light output, study finds
Researchers discovered that microscopic variations in chemical composition sabotage blue perovskite light-emitting diodes—a promising display technology. The finding explains why these devices underperform and points to practical fixes, potentially accelerating commercial development of cheaper, more efficient blue LEDs for next-generation screens.
Originaltitel: Effects of local compositional heterogeneity in mixed halide perovskites on blue electroluminescence
<p>Compositional heterogeneity is commonly observed in mixed bromide/iodide perovskite photoabsorbers, typically with minimal effects on charge carrier recombination and photovoltaic performance. Consistently, it has so far received very limited attention in bromide/chloride-mixed perovskites, which hold particular significance for blue light -emitting diodes. Here, we uncover that even a minor degree of localized halide heterogeneity leads to severe non -radiative losses in mixed bromide/chloride blue perovskite emitters, presenting a stark contrast to general observations in photovoltaics. We not only provide a visualization of the heterogeneity landscape spanning from micro -to sub-microscale but also identify that this issue mainly arises from the initially formed chloride -rich clusters during perovskite nucleation. Our work sheds light on a long-term neglected factor impeding the advancement of blue light -emitting diodes using mixed halide perovskites and provides a practical strategy to mitigate this issue.</p>