Influence of Domain Distribution on Efficiency Roll-Off in Blue Ruddlesden–Popper Perovskite Light-Emitting Diodes

Abstract Over the past decade, quasi-two-dimensional (2D) perovskites leveraging quantum confinement and carrier funneling have enabled promising innovations for the commercialization of full-color displays. However, the relationship between the crystal structures and device performance, particularly on the efficiency roll-off under high current injection, remains unclear. Here, we conducted time- and intensity-dependent optical characterizations, alongside electrical and thermal stability analyses, of quantum well phases with varying thicknesses and phenyl-alkyl-ammonium cations. Our findings reveal that the efficiency roll-off in quasi-2D perovskites with fewer inorganic layers is larger regardless of the spacer cation species. Additionally, we examined the contribution of Auger recombination, charge carrier imbalance, field-induced exciton dissociation, and Joule heating on the efficiency roll-off. We found that the efficiency roll-off is primarily influenced by the first-order recombination and Auger recombination, while other factors play negligible roles. These insights provide design guidelines for organic molecules and multiquantum-well structures toward stable blue perovskite light-emitting diodes.