Indium-rich environmentally-friendly quantum dots (QDs) have received widespread attention due to the absence of cadmium. In this paper, AgInS2 (AIS) QDs are synthesized by hot injection method. By adjusting the ratio of indium/silver (In/Ag = 1, 2, 3, 4, 5), the AIS QDs exhibit a blue shift from 868 nm to 603 nm with the indium composition increases. Therein, the AIS QDs with the ratio of In/Ag = 4 show a highest photoluminescent (PL) quantum yields (QYs) up to 57%. AIS QDs are coated with ZnS shell to passivate the surface defects, and the PL QYs of obtained core/shell AIS/ZnS QDs is increased to 72%. By using these AIS/ZnS QDs as light emitters, light emitting diodes are assembled with a stacked multi-layer structure ITO/PEDOT:PSS/Poly-TPD/QDs/ZnO:Mg/Al. The resulted electroluminescent (EL) device exhibits a maximum external quantum efficiency (EQE) of 1.25% and an open circuit voltage of 4.6 V corresponding to a maximum brightness of 1120 cd m−2. Although the performances of the as fabricated AIS/ZnS-based device lag much behind than those of the Cd-based ones, they are expected to be enhanced with much more studies on the synthesis of the QDs and the optimization of device structure.
The localized surface plasmon resonance (LSPR) behavior of indium-doped ZnO (IZO) nanocrystals synthesized in different solvents was studied. 1-octadecanol, oleic acid, oleyl alcohol, oleyl amine and 1-octadecene were used as solvent(s) and co-solvent(s) in the pyrolysis synthesis of indium-doped ZnO (IZO) nanoparticles. The results showed that the nanocrystals from a solvent system consisting of 1-octadecene, 1-octadecanol, and oleic acid exhibited enhanced LSPR near-infrared radiation absorption without sacrificing transparency in the visible region. The indium-rich core verified using ICP and XPS analysis was shown to be critical for the enhancement. The reaction mechanism of solvents on the generation of indium-rich core was elucidated through a systematic study of the reaction parameters. The interaction between the activating agent, inhibiting agent and solvent, and their effect on tuning the reactivity of dopant and host precursors were important for the formation of a nanostructure with a dopant-rich core. The solvent effect was also found in the synthesis of gallium-doped ZnO and confirmed to be a general phenomenon in the preparation of doped ZnO nanoparticles.
Photocatalytic technology is considered a sound solution to exploit hydrogen energy. Currently, photocatalytic hydrogen production and organic synthesis under simulated sunlight simultaneously have enormous practical significance. Herein, we synthesized Ni@C metal nanoparticles cocatalyst to form a composite photocatalyst with Indium-vacancy-rich In 2 S 3 by the electrostatic self-assembly method. The composite exhibited a hydrogen production rate of 3.52 mmol·g −1 ·h −1 and coupling of benzylamine 8.37 mmol·g −1 ·h −1 . X-ray photoelectron spectroscopy and density functional theory explored the reaction process and mechanism. The charge density difference of the heterojunction surface revealed that the Ni@C interacted with the substrate via both electrostatic interaction and chemical bonds. This confirmed that the electrons rapidly transferred to the cocatalyst under the irradiation of visible light, which was conducive to the surface reduction reaction and greatly inhibited the photogenerated carrier recombination. Moreover, hydrogen adsorption energy further explained the synergistic effect of co-modification of the defect and the fact that noble-metal-free cocatalyst could improve photocatalytic efficiency. This work offers insights into the preparation of new types of photocatalysts which produce hydrogen and high-value chemicals in the future.
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