2 research outputs found
Original Core–Shell Structure of Cubic CsPbBr<sub>3</sub>@Amorphous CsPbBr<sub><i>x</i></sub> Perovskite Quantum Dots with a High Blue Photoluminescence Quantum Yield of over 80%
All-inorganic perovskite
cesium lead halide quantum dots (QDs)
have been widely investigated as promising materials for optoelectronic
application because of their outstanding photoluminescence (PL) properties
and benefits from quantum effects. Although QDs with full-spectra
visible emission have been synthesized for years, the PL quantum yield
(PLQY) of pure blue-emitting QDs still stays at a low level, in contrast
to their green- or red-emitting counterparts. Herein, we obtained
core–shell structured cubic CsPbBr<sub>3</sub>@amorphous CsPbBr<sub><i>x</i></sub> (A-CsPbBr<sub><i>x</i></sub>)
perovskite QDs via a facile hot injection method and centrifugation
process. The core–shell structure QDs showed a record blue
emission PLQY of 84%, which is much higher than that of blue-emitting
cubic CsPbBr<sub>3</sub> QDs and CsPbBr<sub><i>x</i></sub>Cl<sub>3–<i>x</i></sub> QDs. Furthermore, a blue-emitting
QDs-assisted LED with bright pure blue emission was prepared and illustrated
the core–shell QDs’ promising prospect in optoelectrical
application
High-Efficiency Pure-Red CsPbI<sub>3</sub> Quantum Dot Light-Emitting Diodes Enabled by Strongly Electrostatic Potential Solvent and Sequential Ligand Post-treatment Process
Efficient pure-red emission light-emitting diodes (LEDs)
are essential
for high-definition displays, yet achieving pure-red emission is hindered
by challenges like phase segregation and spectral instability when
using halide mixing. Additionally, strongly confined quantum dots
(QDs) produced through traditional hot-injection methods face byproduct
contamination due to poor solubility of metal halide salts in the
solvent octadecene (ODE) at low temperatures. Herein, we introduced
a novel method using a benzene-series strongly electrostatic potential
solvent instead of ODE to prevent PbI2 intermediates and
promote their dissolution into [PbI3]−. Increasing methyl groups on benzene yields precisely sized (4.4
± 0.1 nm) CsPbI3 QDs with exceptional properties:
a narrow 630 nm PL peak with photoluminescence quantum yield (PLQY)
of 97%. Sequential ligand post-treatment optimizes optical and electrical
performance of QDs. PeLEDs based on optimized QDs achieve pure-red
EL (CIE: 0.700, 0.290) approaching Rec. 2020 standards, with an EQE
of 25.2% and T50 of 120 min at initial
luminance of 107 cd/m2