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Ultrabright Near-Infrared Lead-Free Perovskite Light-Emitting Diodes with Negligible Efficiency Roll-Off
Tianjun Liu1, Qichun Gu2, Xinjuan Li3
1Cavendish Laboratory, University of Cambridge, CambridgeCB3 0HE, U.K.
Journal of the American Chemical Society
|July 30, 2026
Summary
This study introduces a novel molecular engineering approach for lead-free tin perovskites, significantly boosting photoluminescence quantum efficiency and enabling high-performance near-infrared LEDs with minimal efficiency roll-off. This breakthrough advances lead-free perovskite technology for optoelectronics.
Area of Science:
- Materials Science
- Solid-State Physics
- Optoelectronics
Background:
- Lead-free halide perovskites offer tunable optoelectronic properties for light-emitting diodes (LEDs).
- Efficiency roll-off in perovskite LEDs is a major limitation, caused by nonradiative recombination and structural instabilities.
- Existing solutions struggle to maintain performance at high current densities.
Purpose of the Study:
- To develop a lead-free perovskite material with improved efficiency and stability for high-current-density applications.
- To investigate the impact of molecular engineering on perovskite semiconductor properties.
- To demonstrate the potential of engineered perovskites in near-infrared LEDs.
Main Methods:
- Molecular engineering of cesium tin iodide (CsSnI3) using N,N'-diphenylthiourea (DPTA).
- Precise control of charge-carrier concentration and lattice growth.
- Characterization using photoluminescence quantum efficiency (PLQE) measurements and high-resolution transmission electron microscopy (HRTEM).
- Fabrication and testing of near-infrared LEDs.
Main Results:
- Achieved a photoluminescence quantum efficiency (PLQE) of 36% at a carrier concentration of 10^18 cm^-3 in DPTA-engineered CsSnI3.
- Uniform local strain distribution in doped films enhanced carrier wave-function overlap, boosting PLQE.
- Fabricated near-infrared LEDs with 13.4% external quantum efficiency (EQE) and peak radiance of 1248 W sr^-1 m^-2.
- Demonstrated minimal efficiency roll-off at current densities exceeding 3500 mA cm^-2.
Conclusions:
- DPTA engineering provides a new strategy for enhancing lead-free perovskites.
- Engineered CsSnI3 exhibits superior optoelectronic properties suitable for high-power applications.
- This work paves the way for electrically pumped perovskite laser diodes and advanced optoelectronic devices.
