Hydrogen Bond-Assisted Dual Passivation for Blue Perovskite Light-Emitting Diodes

Abstract

Although significant progress has been made in the development of green, red, and near-infrared perovskite light-emitting diodes (PeLEDs), blue PeLEDs exhibit inferior performance, owing to various defects and poor carrier injection in solution-processed perovskite films. Thus, this study incorporates dual-passivation additive diphenylphosphinamide (DPPA) into perovskite films, and through density functional theory calculations and experimental characterizations, DPPA has been proven to be an effective passivator. Its phosphine oxide group coordinates with unsaturated lead ions, passivating perovskite defects, while the amino group forms hydrogen bonds with adjacent halide ions, suppressing their migration and further strengthening the passivation effect. Blue quasi-two-dimensional PeLEDs based on DPPA-modified perovskite films achieved an external quantum efficiency of 12.31% with an emission peak at 486 nm. Moreover, the device operational lifetime was extended by 32% with more stable spectra owing to the decreased defect density and suppressed ion migration in the perovskite film.

Surface co-modification enabling efficient and spectrally stable mixed-halide blue light-emitting diodes

“…31 The peak gradually shifts towards low wavenumbers and broadens after adding DPH, indicating the successful doping of NH 4 + and the existence of N–H⋯X that can enhance the stability of the crystal structure. 30,36 Meanwhile, this is indicative of successful doping into the perovskite lattice of NH 4 + , consistent with the XRD and TEM results.…”

Bright and Stable Red Perovskite LEDs under High Current Densities

“…The strong interactions between SFA and I – are evidenced by the clear shifts and broadening of the 127 I NMR spectra for the CsI:SFA samples. The NMR results suggest that SFA effectively interacts with FA + , Pb 2+ , and I – . , Combining FABr with BA molecules, which have only one amino group, has a minimal impact on the 1 H spectrum of FABr. In contrast, incorporating SFA and BSA molecules, which feature sulfone groups, leads to a notable broadening of the FABr’s 1 H spectrum.…”

Precursor Engineering Induced High-Efficiency Electroluminescence of Quasi-Two-Dimensional Perovskites: A Synergistic Defect Inhibition and Passivation Approach

“…The EQE statistics for both LEDs from 22 devices are shown in the inset of Figure d, with average peak EQE values of 11% and 19% for LEDs without and with O-Tg, respectively. It is noteworthy that the EQE of O-Tg-based red Q-2D perovskite LEDs is comparable to those of the best performing pure red LEDs (Table S2), ,− demonstrating the promising potential of synergistic defect inhibition and passivation.…”