Observation of Quantum Confinement in Monodisperse Methylammonium Lead Halide Perovskite Nanocrystals Embedded in Mesoporous Silica.
Hybrid organic-inorganic metal halide perovskites have fascinating electronic properties and have already been implemented in various devices. Although the behavior of bulk metal halide perovskites has been widely studied, the properties of perovskite nanocrystals are less well-understood because synthesizing them is still very challenging, in part because of stability. Here we demonstrate a simple and versatile method to grow monodisperse CH3NH3PbBrxIx-3perovskite nanocrystals inside mesoporous silica templates. The size of the nanocrystal is governed by the pore size of the templates (3.3, 3.7, 4.2, 6.2, and 7.1 nm). In-depth structural analysis shows that the nanocrystals maintain the perovskite crystal structure, but it is slightly distorted. Quantum confinement was observed by tuning the size of the particles via the template. This approach provides an additional route to tune the optical bandgap of the nanocrystal. The level of quantum confinement was modeled taking into account the dimensions of the rod-shaped nanocrystals and their close packing inside the channels of the template. Photoluminescence measurements on CH3NH3PbBr clearly show a shift from green to blue as the pore size is decreased. Synthesizing perovskite nanostructures in templates improves their stability and enables tunable electronic properties via quantum confinement. These structures may be useful as reference materials for comparison with other perovskites, or as functional materials in all solid-state light-emitting diodes.
World Premier International (WPI) Research Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS) , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Victor
V
Malgras
World Premier International (WPI) Research Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS) , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Satoshi
S
Tominaka
International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS) , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
James W
JW
Ryan
World Premier International (WPI) Research Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS) , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Joel
J
Henzie
World Premier International (WPI) Research Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS) , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Toshiaki
T
Takei
Research and Utilization Division, Japan Synchrotron Radiation Research Institute , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan.
Koji
K
Ohara
World Premier International (WPI) Research Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS) , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Yusuke
Y
Yamauchi