Preparation and Properties of Nano ZnO Dye Sensitized Solar Cells on (Titanium) Substrates

Nowadays, the development of science and technology has been increasing demand for energy. Energy problem has become a bottleneck to restrict the development of international social economy. People pay more and more attention to the development and research of renewable resources. Solar energy is a kind of renewable resource with great potential and no pollution. The commercialized solar cells are mainly silicon solar cells, among which the conversion efficiency of single silicon solar cells is the highest, but the cost of silicon solar cells is high. Therefore, people have been exploring new materials, among which titanium based nano ZnO dye sensitized solar cells have been paid more and more attention by scientists at home and abroad. Based on this, the preparation and performance of nano ZnO dye sensitized solar cells based on titanium are studied. In this paper, the optical anode materials of DSSC are used as the research objects. Three-dimensional ZnO nanoband, one-dimensional graded ZnO nanotube array and one-dimensional sub grade ZnO nanowire array are prepared by anodizing and hydrothermal synthesis. The photovoltaic properties of the three materials are studied. One dimensional graded ZnO, nanotube array films were prepared by two-step hydrothermal synthesis. One dimensional hierarchical ZnO nanowire array is obtained by two-step hydrothermal synthesis. The results show that DSSC is assembled by one-dimensional graded ZnO nanotube array film, and the photoelectric conversion efficiency is 5.1%. Compared with one-dimensional ZnO nanowire array, the efficiency is improved by nearly 90%. The ZnO nanowire of the sub grade is used instead of DSSC The efficiency of photoelectric conversion is only 4% in the photoanode, which is higher than that of the smooth ZnO nanowire photocell.

Highly sensitive and flexible pressure sensors using position- and dimension-controlled ZnO nanotube arrays grown on graphene films

A facile and novel technique for the fabrication of pressure sensors is reported based on the hybridization of one-dimensional nanomaterials and two-dimensional graphene film. In particular, piezoelectric pressure sensors are fabricated by using vertically aligned and position- and dimension-controlled ZnO nanotube arrays grown on graphene layers. Graphene layers act not only as substrates for catalyst-free growth of high-quality ZnO nanotubes but also as flexible conduction channels connecting ZnO nanotubes and metal electrodes. Freestanding and flexible sensors have been efficiently obtained via mechanical lift-off of hybrid ZnO nanotube/graphene film structures and by exploiting the weak van der Waals forces existing between the graphene film and the original substrates. A prototype of such devices shows a high pressure sensitivity (−4.4 kPa−1), which would enable the detection of weak flows of inert gas. The relatively low wall thickness and large length of the ZnO nanotubes suggest a relatively high sensitivity to external pressures. The obtained nanotube sensors are attached to the philtrum and wrist of a volunteer and used to monitor his breath and heart rate. Overall, the prototype hybrid sensing device has great potential as wearable technology, especially in the sector of advanced healthcare devices.

CuO-Decorated ZnO Nanotube-based Sensor for Detecting CO Gas: A First-Principles Study

Understanding the effect of decorating of copper oxide (CuO) on Carbon monoxide (CO) adsorption at zinc oxide nanotube is crucial for designing a high performance CO gas sensor. In this work, CO sensing properties of copper oxide-decorated zinc oxide (CuO-ZnO) nanotube is studied theoretically by employing first-principles density functional theory for the first time. The stability, adsorption mechanism, density of states, and change in electrical conductivity are studied. The results of calculating the adsorption energy show strong chemical adsorption of CO on CuO-ZnO nanotubes. The adsorption energy of CO on CuO-ZnO nanotube is calculated as 7.5 times higher than that on ZnO nanotube. The results of the Mulliken charge analysis reveal that electron transfer occurs from CO molecules to CuO-ZnO nanotubes. Additionally, the electrical conductivity of CuO-ZnO nanotubes significantly changes after adsorption of CO at room temperature. According to these studies, CuO-ZnO nanotube sensors can be used for the detection of CO gas. The results are in excellent agreement with the reported experimental results.