RESUMEN
I-III-VI-based semiconductor quantum dots (QDs) have been intensively explored because of their unique controllable optoelectronic properties. Here we report one-pot synthesis of Na-doped Ag-In-Ga-S (AIGS) QDs incorporated in a Ga2O3 matrix. The obtained QDs showed a sharp band-edge photoluminescence peak at 557 nm without a broad-defect site emission. The PL quantum yield (QY) of such QDs was 58%, being much higher than that of AIGS QDs without Na+ doping, 29%. The obtained Na-doped AIGS/Ga2O3 composite particles were used as an emitting layer of green QD light-emitted diodes. A sharp electroluminescence (EL) peak was observed at 563 nm, being similar to that in the PL spectrum of the QDs used. The external quantum efficiency of the device was 0.6%.
RESUMEN
Narrowing the emission peak width and adjusting the peak position play a key role in the chromaticity and color accuracy of display devices with the use of quantum dot light-emitting diodes (QD-LEDs). In this study, we developed multinary Cu-In-Ga-S (CIGS) QDs showing a narrow photoluminescence (PL) peak by controlling the Cu fraction, i.e., Cu/(In+Ga), and the ratio of In to Ga composing the QDs. The energy gap of CIGS QDs was enlarged from 1.74 to 2.77 eV with a decrease in the In/(In+Ga) ratio from 1.0 to 0. The PL intensity was remarkably dependent on the Cu fraction, and the PL peak width was dependent on the In/(In+Ga) ratio. The sharpest PL peak at 668 nm with a full width at half maximum (fwhm) of 0.23 eV was obtained for CIGS QDs prepared with ratios of Cu/(In+Ga) = 0.3 and In/(In+Ga) = 0.7, being much narrower than those previously reported with CIGS QDs, fwhm of >0.4 eV. The PL quantum yield of CIGS QDs, 8.3%, was increased to 27% and 46% without a PL peak broadening by surface coating with GaSx and Ga-Zn-S shells, respectively. Considering a large Stokes shift of >0.5 eV and the predominant PL decay component of â¼200-400 ns, the narrow PL peak was assignable to the emission from intragap states. QD-LEDs fabricated with CIGS QDs surface-coated with GaSx shells showed a red color with a narrow emission peak at 688 nm with a fwhm of 0.24 eV.
RESUMEN
Chemodynamic therapy (CDT), which consumes endogenous hydrogen peroxide (H2O2) to generate reactive oxygen species (ROS) and causes oxidative damage to tumor cells, shows tremendous promise for advanced cancer treatment. However, the rate of ROS generation based on the Fenton reaction is prone to being restricted by inadequate H2O2 and unattainable acidity in the hypoxic tumor microenvironment. We herein report a multifunctional nanoprobe (BCGCR) integrating bimodal imaging and photothermal-enhanced CDT of the targeted tumor, which is produced by covalent conjugation of bovine serum albumin-stabilized CuS/Gd2O3 nanoparticles (NPs) with the Cy5.5 fluorophore and the tumor-targeting ligand RGD. BCGCR exhibits intense near-infrared (NIR) fluorescence and acceptable r1 relaxivity (â¼15.3 mM-1 s-1) for both sensitive fluorescence imaging and high-spatial-resolution magnetic resonance imaging of tumors in living mice. Moreover, owing to the strong NIR absorbance from the internal CuS NPs, BCGCR can generate localized heat and displays a high photothermal conversion efficiency (30.3%) under 980 nm laser irradiation, which enables photothermal therapy and further intensifies ROS generation arising from the Cu-induced Fenton-like reaction for enhanced CDT. This synergetic effect shows such an excellent therapeutic efficacy that it can ablate xenografted tumors in vivo. We believe that this strategy will be beneficial to exploring other advanced nanomaterials for the clinical application of multimodal imaging-guided synergetic cancer therapies.