RESUMO
For the first time, quaternary chalcogenide CuNi2InS4 nanocrystals with a wurtzite structure have been designed and fabricated as a new magnetic semiconductor. The phase structure analysis suggests that the synthesized wurtzite CuNi2InS4 phase has a disordered structure in which Cu+, Ni2+, and In3+ ions share the same lattice site of the unit cell with a random cation distribution. The prepared CuNi2InS4 nanocrystals have uniform bullet-like morphology, small size distribution, good monodispersity, and high crystallinity. The magnetic properties investigation reveals that the wurtzite CuNi2InS4 nanocrystals can exhibit a weak ferromagnetic moment with the blocking temperature at around 13 K thanks to the disordered wurtzite structure and the high content of magnetic Ni2+ ions. As for the semiconducting properties, the as-obtained wurtzite CuNi2InS4 nanocrystals show a strong and broad visible light absorption and have a direct bandgap of 1.45 eV. Due to their favorable optical properties, the fabricated thin film of CuNi2InS4 nanocrystals exhibits a good photoelectric response to the solar spectrum, which makes the obtained new phase potential candidate for applications in the photovoltaics. This work demonstrates a new metastable I-II2-III-VI4 chalcogenide that can be used to render multiple functionalities and applications.
RESUMO
Multifunctional multinary metal chalcogenides have long been a research hotspot in the field of materials chemistry due to their rich composition, flexible structure, excellent properties and wide range of applications. However, the exploration of complex quinary chalcogenides is still challenging. In this work, for the first time, we have developed the controlled synthesis of quinary Cu3NiInSnS6 nanocrystals, realizing the selective preparation of hexagonal wurtzite and cubic zinc blende metastable phases by simply tuning the sulfur source. The phase structure analysis reveals that both metastable phases possess a disordered structure with a random distribution of metal atoms in the unit cells. The fabricated wurtzite and zinc blende-structure Cu3NiInSnS6 nanocrystals have a direct band gap of 1.82 and 1.94 eV, respectively, and both exhibit superparamagnetic behavior at low temperatures. This work is of great significance for the development of novel multifunctional materials based on metastable multinary metal chalcogenide phases.
RESUMO
Near-infrared (NIR) light-induced photothermal cancer therapy using nanomaterials as photothermal agents has attracted considerable research interest over the past few years. As the key factor in photothermal therapy systems, a variety of photothermal agents have been developed. However, the exploration of novel photothermal therapy nanoplatforms with high NIR absorption remains a significant challenge, especially those working in both NIR-I and NIR-II windows. In this work, Bi19S27I3 nanorods with remarkably high absorption covering the whole visible light to the entire NIR-I and NIR-II regions have been successfully prepared through a facile solvothermal approach. The as-synthesized Bi19S27I3 nanorods have a high photothermal conversion efficiency of 42.7% at 808 nm (NIR-I) and 41.5% at 1064 nm (NIR-II), making them a promising candidate for photothermal therapy. In vitro cell viability assay reveals that the Bi19S27I3 sample has good biocompatibility and exhibits significant cell-killing effect under NIR irradiation. In vivo anti-tumor experiments demonstrate that the tumor growth can be effectively inhibited by fatal hyperthermia ablation mediated by Bi19S27I3 nanorods under the irradiation of an 808 nm or 1064 nm laser. Therefore, this study should be primarily beneficial for the development of new materials for NIR photothermal therapy applications.