Green emission of indium oxide via hydrogen treatment

In this work, we prepared hydrogen treated indium oxide (H₂-In₂O₃) and investigated the effect of hydrogen treatment on the optical and photoluminescence properties of In₂O₃. Hydrogen treatment has no influence on the crystal structure, but alters the intrinsic electronic structure and optical properties via introducing hydrogen induced defects such as shallow donor states (near the conduction band) and singly ionized oxygen vacancies in H₂-In₂O₃. Both air-In₂O₃ (air calcinated) and H₂-In₂O₃ show intense blue emission under UV excitation (280 nm). However, hydrogen treated In₂O₃ exhibited an additional green emission, which is absent in air-In₂O₃. This green emission arises from the passivation of singly ionized oxygen vacancies by hydrogen treatment. Hydrogen treatment could be a promising strategy to tune the electronic and optical properties of In₂O₃.

H₂-treated In₂O₃ gives rise to photoemission ranging from blue to green-yellow, while air-calcined In₂O₃ shows only blue emission. EPR and optical spectroscopies reveal singly ionized oxygen vacancies induced by H₂ treatment responsible for the green-yellow emission.

Hydrothermal synthesis of In2O3 nanoparticles hybrid twins hexagonal disk ZnO heterostructures for enhanced photocatalytic activities and stability

In₂O₃ nanoparticles hybrid twins hexagonal disk (THD) ZnO with different ratios were fabricated by a hydrothermal method. The as-obtained ZnO/In₂O₃ composites are constituted by hexagonal disks ZnO with diameters of about 1 μm and In₂O₃ nanoparticles with sizes of about 20-50 nm. With the increase of In₂O₃ content in ZnO/In₂O₃ composites, the absorption band edges of samples shifted from UV to visible light region. Compared with pure ZnO, the ZnO/In₂O₃ composites show enhanced photocatalytic activities for degradation of methyl orange (MO) and 4-nitrophenol (4-NP) under solar light irradiation. Due to suitable alignment of their energy band-gap structure of the In₂O₃ and ZnO, the formation of type п heterostructure can enhance efficient separation of photo-generate electro-hole pairs and provides convenient carrier transfer paths.

Synthesis of uniform cadmium sulphide thin film by the homogeneous precipitation method on cadmium telluride nanorods and its application in three-dimensional heterojunction flexible solar cells

High-density CdTe nanorod arrays are successfully embedded in a uniform and compact CdS layer, forming a novel three-dimensional (3D) CdTe NRs/CdS heterojunction structure. The CdS layer is prepared by homogeneous precipitation (HP) method using decomposition of urea. The effects of temperature and concentration of reactants on the growth and composition of CdS film are investigated in detail. The results demonstrate that the temperature affects the thermal decomposition of urea significantly, and the concentration of CdCl₂ and CS (NH₂)₂ plays an essential role in the compositional ratio of CdS film. Further investigations reveal that, in comparison with the traditional precipitation method, a better coverage of CdS on the surface of CdTe NRs can be obtained by HP method due to the slow and even hydrolysis of urea. Moreover, photovoltaic performance of the novel CdTe NRs/CdS 3D photovoltaic device is also investigated. This study demonstrates that the 3D heterostructure has potential application in thin film solar cells, and the successful deposition of CdS layer on the surface of CdTe NRs by HP method suggests a promising technique for large-scale fabrication of these solar cells.