Steric Effects in Ruddlesden–Popper Blue Perovskites for High Quantum Efficiency

Abstract

AbstractRuddlesden–Popper perovskites (RPPs) feature enhanced stability compared to their bulk counterparts and attract attention for potential applications in light‐emitting diodes (LEDs). However, to date, blue‐emitting RPPs rely on halide compositional tuning, resulting in spectral shifts due to halide segregation under photo‐/electrical‐excitation. Here, efficient blue‐emitting materials with single‐halide RPPs using organic spacer engineering are reported. Experimental and computational results show that the (110)‐oriented thin films exhibit larger bandgap and enhanced stability regardless of the choice of spacers, relative to the (100)‐oriented RPPs. The correlation between the lattice structures and optoelectronic properties reveals that this new class of RPPs exhibits sky‐blue emission at 483 nm with a quantum efficiency of ≈62%. Spearman correlation between the steric size of the spacers and the bandgap is estimated to be 92%, showing that the steric effect is crucial influencers. The protocol and strategy established in this study can be exploited to develop blue perovskite LEDs.