In Situ Preparation of Metal Halide Perovskite Nanocrystal Thin Films for Improved Light-Emitting Devices.
Hybrid organic-inorganic halide perovskite semiconductors are attractive candidates for optoelectronic applications, such as photovoltaics, light-emitting diodes, and lasers. Perovskite nanocrystals are of particular interest, where electrons and holes can be confined spatially, promoting radiative recombination. However, nanocrystalline films based on traditional colloidal nanocrystal synthesis strategies suffer from the use of long insulating ligands, low colloidal nanocrystal concentration, and significant aggregation during film formation. Here, we demonstrate a facile method for preparing perovskite nanocrystal films in situ and that the electroluminescence of light-emitting devices can be enhanced up to 40-fold through this nanocrystal film formation strategy. Briefly, the method involves the use of bulky organoammonium halides as additives to confine crystal growth of perovskites during film formation, achieving CH3NH3PbI3and CH3NH3PbBr3perovskite nanocrystals with an average crystal size of 5.4 ± 0.8 nm and 6.4 ± 1.3 nm, respectively, as confirmed through transmission electron microscopy measurements. Additive-confined perovskite nanocrystals show significantly improved photoluminescence quantum yield and decay lifetime. Finally, we demonstrate highly efficient CH3NH3PbI3red/near-infrared LEDs and CH3NH3PbBr3green LEDs based on this strategy, achieving an external quantum efficiency of 7.9% and 7.0%, respectively, which represent a 40-fold and 23-fold improvement over control devices fabricated without the additives.
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Lianfeng
0000-0003-0967-6536
L
Zhao
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Yao-Wen
YW
Yeh
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Nhu L
NL
Tran
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Fan
F
Wu
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Zhengguo
Z
Xiao
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Ross A
RA
Kerner
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
YunHui L
0000-0002-0817-8757
YL
Lin
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Gregory D
0000-0003-3336-7960
GD
Scholes
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Nan
N
Yao
Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States.
Barry P
0000-0003-4409-8751
BP
Rand
in situ preparation; light-emitting diodes; nanocrystal synthesis; organic−inorganic hybrid perovskites; perovskite stability