Efficient Blue Electroluminescence Using Quantum-Confined Two-Dimensional Perovskites.
Solution-processed hybrid organic-inorganic lead halide perovskites are emerging as one of the most promising candidates for low-cost light-emitting diodes (LEDs). However, due to a small exciton binding energy, it is not yet possible to achieve an efficient electroluminescence within the blue wavelength region at room temperature, as is necessary for full-spectrum light sources. Here, we demonstrate efficient blue LEDs based on the colloidal, quantum-confined 2D perovskites, with precisely controlled stacking down to one-unit-cell thickness (n = 1). A variety of low-k organic host compounds are used to disperse the 2D perovskites, effectively creating a matrix of the dielectric quantum wells, which significantly boosts the exciton binding energy by the dielectric confinement effect. Through the Förster resonance energy transfer, the excitons down-convert and recombine radiatively in the 2D perovskites. We report room-temperature pure green (n = 7-10), sky blue (n = 5), pure blue (n = 3), and deep blue (n = 1) electroluminescence, with record-high external quantum efficiencies in the green-to-blue wavelength region.
Sudhir
S
Kumar
Jakub
J
Jagielski
Sergii
S
Yakunin
School of Mathematics and Physics, Queen's University Belfast , Belfast BT7 1NN, North Ireland, United Kingdom.|School of Chemistry and Chemical Engineering, Queen's University Belfast , Belfast BT9 5AL, United Kingdom.
Peter
P
Rice
Department of Chemical Engineering and Materials Science, Yuan Ze University , Taoyuan 320, Taiwan.
Yu-Cheng
YC
Chiu
Department of Mechanical Engineering, Materials Science & Engineering Program, Florida State University , Tallahassee, Florida 32310, United States.
Mingchao
M
Wang
Georgian
G
Nedelcu
Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
Yeongin
Y
Kim
Department of Mechanical Engineering, Materials Science & Engineering Program, Florida State University , Tallahassee, Florida 32310, United States.
Shangchao
S
Lin
School of Mathematics and Physics, Queen's University Belfast , Belfast BT7 1NN, North Ireland, United Kingdom.|School of Chemistry and Chemical Engineering, Queen's University Belfast , Belfast BT9 5AL, United Kingdom.
Elton J G
EJG
Santos
Empa - Swiss Federal Laboratories for Materials Science and Technology , CH-8600 Dübendorf, Switzerland.
Maksym V
MV
Kovalenko
Chih-Jen
CJ
Shih
2D materials; colloidal synthesis; hybrid perovskites; light-emitting diodes