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Mixed Lead–Tin Halide Perovskites for Efficient and Wavelength‐Tunable Near‐Infrared Light‐Emitting Diodes
Author(s) -
Qiu Weiming,
Xiao Zhengguo,
Roh Kwangdong,
Noel Nakita K.,
Shapiro Andrew,
Heremans Paul,
Rand Barry P.
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201806105
Subject(s) - materials science , optoelectronics , light emitting diode , perovskite (structure) , quantum efficiency , diode , tin , halide , electroluminescence , nanotechnology , inorganic chemistry , chemistry , layer (electronics) , chemical engineering , engineering , metallurgy
Near‐infrared (NIR) light‐emitting diodes (LEDs), with emission wavelengths between 800 and 950 nm, are useful for various applications, e.g., night‐vision devices, optical communication, and medical treatments. Yet, devices using thin film materials like organic semiconductors and lead based colloidal quantum dots face certain fundamental challenges that limit the improvement of external quantum efficiency (EQE), making the search of alternative NIR emitters important for the community. In this work, efficient NIR LEDs with tunable emission from 850 to 950 nm, using lead–tin (Pb‐Sn) halide perovskite as emitters are demonstrated. The best performing device exhibits an EQE of 5.0% with a peak emission wavelength of 917 nm, a turn‐on voltage of 1.65 V, and a radiance of 2.7 W Sr −1 m −2 when driven at 4.5 V. The emission spectra of mixed Pb‐Sn perovskites are tuned either by changing the Pb:Sn ratio or by incorporating bromide, and notably exhibit no phase separation during device operation. The work demonstrates that mixed Pb‐Sn perovskites are promising next generation NIR emitters.