Electrokinetic Phenomenon Based On Nanoporous TiO₂ Films

With the intelligent and connected world coming,flexible wearable electronic devices appear in people's daily life,the energetic issues that accompany it are becoming increasingly prominent.The self-powered technology that harvests various environmental energies and converts them into electrical energy has important significance for solving the problem of supplying electronic devices.The electrokinetic phenomenon-based microfluidic generator can convert the mechanical and low-grade thermal energy around the environment into electrical energy through the double layer effect,which is an important way to build self-powered systems.In this thesis,we firstly summarize the principle and development of electrokinetic phenomena,and particularly introduce the latest research progress of evaporation induced water flow generation.This unique and novel phenomenon of power generation has been based on carbon-based materials since the report,and its universality has not yet been verified.For the first time,this paper confirms that the nanoporous titanium dioxide?TiO₂?film can also generate electricity by evaporation-induced water flowing,and this electrokinetic phenomenon has ultraviolet light response characteristics.Finally,the evaporation power performance of nanoporous TiO₂ film and its potential applications in the field of light-controlled generators are studied in detail.The research work of this dissertation is of great significance for deepening the understanding of evaporation generators and expanding their application scope.The main research content is as follows?1?Preparation of nanoporous titanium dioxide films by full-printing method:Dioxide slurry was prepared by mixing titanium dioxide,ethyl cellulose and turpentine-permeated alcohol.The nanoporous titanium dioxide film was finally formed after the slurry being shaved to a thin film and then the film being annealed,last,we study the hydrophilic and hydrophobic properties and UV absorption of the film.?2?Electrokinetic phenomena of nanoporous TiO₂ film:We fabricate the nanoporous TiO₂ thin film microfluidic generator through packaging.We found that water evaporation is a main influence factor of the generating performance,and further confirmed that the voltage is caused by evaporation induced water flow in the nanochannel,which belongs to the electrokinetic effect.We found that the device has a UV-responsive property,the open-circuit voltage is significantly reduced under ultraviolet irradiation,and we further studied the influence of the ultraviolet light intensity and wavelength on the open-circuit voltage.We proposed the mechanism of UV regulation:TiO₂ absorbs UV light and generates electron-hole separation,and the vacancies transfer to the surface of the TiO₂particles to reduce their Zeta Potential,reducing the electrokinetic effect of nanochannels and resulting in a decrease in the open circuit voltage of the TiO₂ generator.These results have potential value for implementing self-powered UV detection systems.?3?TiO₂-ITO microfluidic generator:We fabricated the TiO₂-ITO evaporation generator by magnetron sputtering indium tin oxide?ITO?on the surface of a TiO₂ film,ITO can significantly reduce the resistance of the film,which results in a significant increase in the output performance of a single device.We found that the device has a UV-responsive property and the response performance is much better than before.A"power generation tree"based on TiO₂-ITO devices was manufactured.By connecting the four devices in series,respectively,and the electronic thermometer was successfully driven.