2 research outputs found
Template-Free Uniform-Sized Hollow Hydrogel Capsules with Controlled Shell Permeation and Optical Responsiveness
This study has established a robust and straightforward
method
for the fabrication of uniform polyÂ(vinylamine) hydrogel capsules
without using templates that combines the dispersion polymerization
and the sequential hydrolysis/cross-linking. The particle sizes are
determined by the degree of cross-linking as well as by the cross-linking
reaction time, while the shell thickness is independent of these variables.
Diffusion-limited reactions occur at the periphery of the particles,
leading to the formation of hydrogel shells with a constant thickness.
The treatment of the surfaces of hollow hydrogel capsules with oppositely
charged biopolymers limits the permeability through the shell of species
even with low molecular weights less than 400 g/mol. Furthermore,
we demonstrated that the hydrogel shell phase decorated with Au nanoparticles
can be optically ruptured by exposure to laser pulse, a feature that
has potential uses in optically responsive drug delivery
Bright and Efficient Full-Color Colloidal Quantum Dot Light-Emitting Diodes Using an Inverted Device Structure
We report highly bright and efficient inverted structure
quantum
dot (QD) based light-emitting diodes (QLEDs) by using solution-processed
ZnO nanoparticles as the electron injection/transport layer and by
optimizing energy levels with the organic hole transport layer. We
have successfully demonstrated highly bright red, green, and blue
QLEDs showing maximum luminances up to 23 040, 218 800,
and 2250 cd/m<sup>2</sup>, and external quantum efficiencies of 7.3,
5.8, and 1.7%, respectively. It is also noticeable that they showed
turn-on voltages as low as the bandgap energy of each QD and long
operational lifetime, mainly attributed to the direct exciton recombination
within QDs through the inverted device structure. These results signify
a remarkable progress in QLEDs and offer a practicable platform for
the realization of QD-based full-color displays and lightings