Fabrication of ZnO Ceramics with Defects by Spark Plasma Sintering Method and Investigations of Their Photoelectrochemical Properties

Abstract

ZnO, as an important semiconductor material, has attracted much attention due to its excellent physical properties, which can be widely used in many fields. Notably, the defects concentration and type greatly affect the intrinsic properties of ZnO. Thus, controllable adjustment of ZnO defects is particularly important for studying its photoelectric properties. In this work, we fabricated ZnO ceramics (ZnO(C)) with different defects through spark plasma sintering (SPS) process by varying sintering temperature and using reduction environment. The experimental results indicate that the changes of color and light absorption in as-prepared ZnO originate from the different kinds of defects, i.e., oxygen vacancies (VO), interstitial zinc (Zni), and Zinc vacancies (VZn). Moreover, with the increase in calcination temperature, the concentration of oxygen defects and interstitial zinc defects in the ceramics increases gradually, and the conductivity of the ceramics is also improved. However, too many defects are harmful to the photoelectrochemical properties of the ceramics, and the appropriate oxygen defects can improve the utilization of visible light.

YAG:Ce Nanophosphors Synthesized by the Polymer–Salt Method for White LEDs with Isomorphic Substitution of Yttrium by Gadolinium

“…Therefore, structural defects engineering based on the formation of intrinsic defects is a way to modify the structural and luminescent properties of materials. For example, the generation of defects in ZnO allows modifying its luminescence spectra [8][9][10][11]. In addition to the formation of such defects as vacancies, interstitial hydrogen or other elements, it is possible to change smaterials' properties by using the partial substitution of some ions by ions with similar properties [12][13][14][15].…”

Кинетика адсорбции и фотокаталитического разложения диазокрасителя нанокомпозитом ZnO-MgO

“…Наличие структурных дефектов также оказывает существенное влияние на оптические, электрические и фотокаталитические свойства ZnO [9,10]. Для оксида цинка характерны такие структурные дефекты, как кислородные вакансии (V o ), межрешеточный цинк (Zn i ) и водород (H i ) [11,12].…”

Nanohollow Titanium Oxide Structures on Ti/FTO Glass Formed by Step-Bias Anodic Oxidation for Photoelectrochemical Enhancement

“…In electrochemical devices, oxidation and reduction occur on the surfaces of photosensitive electrodes with the help of extra photoinduced charged carriers, which can be used to enhance chemical reactions and sensing performance. Therefore, the most common materials, including titanium oxide (TiO 2 ) [ 12 , 13 ], ferric oxide (Fe 2 O 3 ) [ 14 , 15 ] and zinc oxide (ZnO) [ 16 , 17 ], have been investigated widely for decades due to their natural abundance, high chemical stabilities, low costs and low toxicities, especially for realizing superior performance by means of various nanostructures [ 18 ]. TiO 2 is the most promising material due to its various fabrication techniques and biocompatibility [ 19 ].…”