Publications by authors named "A-Ra Hong"

In this study, we synthesized NaYF-based downshifting nanophosphors (DSNPs), and fabricated DSNP-polydimethylsiloxane (PDMS) composites. Nd ions were doped into the core and shell to increase absorbance at 800 nm. Yb ions were co-doped into the core to achieve intense near-infrared (NIR) luminescence.

View Article and Find Full Text PDF

In this study, heavy-metal-free orange light-emitting ZnSe:Mn/ZnS doped-core/shell (d-C/S) quantum dots (QDs) were synthesized using a nucleation doping strategy. To synthesize high quality d-C/S QDs with high photoluminescence (PL) quantum yield (QY), the Mn concentration was optimized. The resulting ZnSe:Mn(5%)/ZnS d-C/S QDs showed a high PL QY of 83.

View Article and Find Full Text PDF
Article Synopsis
  • A new hybrid plasmonic upconversion (UC) architecture combines a hierarchical plasmonic film and a polymeric microlens array to boost photodetection efficiency at 1550 nm.
  • The design leverages plasmonic metasurfaces and nanoassembly films to create an intense electromagnetic field, enhancing UC emission through amplified plasmonic coupling.
  • Coupled with a triple-cation perovskite photodetector, this setup achieves remarkable responsivity and detectivity, outperforming traditional devices by over 10 times at low power densities.
View Article and Find Full Text PDF

Here, excitation orthogonalized red/green/blue upconversion luminescence (UCL)-based full-color tunable rare-earth (RE) ion-doped upconversion nanophosphors (UCNPs) are reported. The LiREF-based core/sextuple-shell (C/6S) UCNPs are synthesized, and they consist of a blue-emitting core, green-emitting inner shell, and red-emitting outer shell, with inert intermediate and outermost shells. The synthesized C/6S UCNPs emit blue, green, and red light under 980, 800, and 1532 nm, respectively.

View Article and Find Full Text PDF

In this study, Li-based blue- and green-emitting core@shell (C@S) upconversion nanophosphors (UCNPs) and NaGdF-based red-emitting C@S UCNPs were synthesized, and IR-808 dyes were conjugated with the C@S UCNPs to enhance upconversion (UC) luminescence. The surface of the as-synthesized C@S UCNPs, which was originally capped with oleic acid, was modified with BF to conjugate the IR-808 dye having a carboxyl functional group to the surface of the UCNPs. After the conjugation with IR-808 dyes, absorbance of the UCNPs was significantly increased.

View Article and Find Full Text PDF

In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near-infrared (NIR) light are reported. When a NaYF:Nd,Yb active-shell is formed on the 12.7 nm sized NaGdF:Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red, depending on the Ce concentration under excitation with 800 nm NIR light.

View Article and Find Full Text PDF

Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F:Yb,Er and Li(Gd,Y)F:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF shell.

View Article and Find Full Text PDF

Colloidal quantum dots (QDs) are attractive candidates for future lighting technology. However, in contrast to display applications, the realization of balanced white lighting devices remains conceptually challenging. Here, we demonstrate two-component white light-emitting QD-LEDs with high color rendering indices (CRI) up to 78.

View Article and Find Full Text PDF

The core/shell-structured upconversion nanophosphors (UCNPs) and Cd-free CuInS(2)/ZnS quantum dots (QDs) were synthesized via coprecipitation and hot-injection methods, respectively, and they were applied to near infrared (NIR) photodetectors. The β-NaYF(4):Yb,Er/β-NaYF(4) UCNPs emitted intense visible light peaking at 522, 542, and 656 nm via (2)H(11/2), (4)S(3/2), and (4)F(9/2)→(4)I(15/2) transitions under excitation with 980 nm NIR light. The core/shell UCNPs showed 6.

View Article and Find Full Text PDF

The development of a simple and reliable method for nanoparticles-based ink in an aqueous solution is still a challenge for its inkjet printing application. Herein, we demonstrate the inkjet printing of fractal-aggregated silver (Ag) electrode lines on substrates. Spherical, monodisperse Ag nanoparticles have been synthesized using silver nitrate as a precursor, ethylene glycol as a reducing agent, and polyvinyl pyrrollidone as a capping agent.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessionjk49tcik9mo60dp351m341ci6kf7eh8d): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once