A multifunctional self-assembled monolayer for perovskite lasing diodes

Abstract Perovskite lasing diodes (PeLDs) require charge transport, optical gain, resonant feedback and high-density electrical injection to be integrated within a single thin-film device. Conventional hole transport materials (HTM) can, however, introduce non-radiative recombination and optical loss in nanophotonic cavities. Here we develop RS-3, a self-assembled monolayer that acts as a multifunctional hole-transport contact. The ultrathin RS-3 layer reduces buried-interface loss, increases net modal gain and preserves the periodic profile of the distributed-feedback (DFB) cavity after deposition of the quasi-two-dimensional N2F8 gain layer, enabling us to realize room-temperature current-assisted lasing under synchronized optical–electrical co-injection. RS-3-based light-emitting diodes also show lower turn-on voltage, higher current density and higher luminance than poly(9-vinylcarbazole)-based controls. Under pulsed optical pumping, the complete device lases near 550 nm at a threshold of 28 μJ cm⁻². With synchronized optical–electrical co-injection, the threshold decreases monotonically to 19 μJ cm⁻² as the pulsed current density increases to 1.30 kA cm⁻², with a minimum linewidth of 0.25 nm.