Synergistic passivation and stepped-dimensional perovskite analogs enable high-efficiency near-infrared light-emitting diodes

Abstract

Formamidinium lead iodide (FAPbI3) perovskites are promising emitters for near-infrared light-emitting diodes. However, their performance is still limited by defect-assisted nonradiative recombination and band offset-induced carrier aggregation at the interface. Herein, we introduce a couple of cadmium salts with acetate or halide anion into the FAPbI3 perovskite precursors to synergistically passivate the material defects and optimize the device band structure. Particularly, the perovskite analogs, containing zero-dimensional formamidinium cadmium iodide, one-dimensional δ-FAPbI3, two-dimensional FA2FAn-1PbnI3n+1, and three-dimensional α-FAPbI3, can be obtained in one pot and play a pivotal and positive role in energy transfer in the formamidinium iodide-rich lead-based perovskite films. As a result, the near-infrared FAPbI3-based devices deliver a maximum external quantum efficiency of 24.1% together with substantially improved operational stability. Combining our findings on defect passivation and energy transfer, we also achieve near-infrared light communication with device twins of light emitting and unprecedented self-driven detection.

A Multifunctional Additive Strategy Enables Efficient Pure‐Blue Perovskite Light‐Emitting Diodes

“…[1][2][3][4][5] The external quantum efficiency (EQE) of perovskite LEDs has exceeded 20% DOI: 10.1002/adma.202302161 in the green to near-infrared wavelengths, making them comparable to commercial organic LEDs (OLED), owing to their excellent optical and electrical properties. [1,[6][7][8][9][10][11][12] Specifically, high-efficiency sky-blue emissive PeLEDs have already shown the great potential of blue emission, with the EQE reaching 18% at 480 nm. [1] However, sky-blue emission has not been enough to meet the wide color gamut and fullcolor display requirements for the Rec.…”

Enhanced efficiency and stability of blue perovskite light-emitting diodes through dual defect passivation

“…[4][5][6] Many strategies including tuning dimensionality, controlling crystallization, and defect passivation have been widely used to improve the quality of perovskites, resulting in significant progress in near-infrared, red and green perovskite LEDs. [7][8][9][10][11] However, blue perovskite LEDs, which are typically obtained by using a mixture of chloride and bromide, lag behind other color devices. On one hand, the large bandgap of blue perovskites and the different crystallization rates of chloride/bromide perovskites lead to more intrinsic defects.…”

High Efficiency Near‐Infrared Perovskite Light Emitting Diodes With Reduced Rolling‐Off by Surface Post‐Treatment

“…[1][2][3] Significant progress has been obtained with above 20% external quantum efficiency (EQE). [4][5][6][7] However, most of the PeLED have a serious EQE rolling-off under high current density. [8,9] Unlike QLEDs and low-dimensional PeLED, 3D PeLED does not restrict charge carriers, and its Auger recombination is not too severe to cause the EQE rolling off.…”