Preparation And Application Of CuO/TiO₂Film For Dye-sensitized Solar Cells

With the development of society and economy,in terms of energy using,People use energy fromindirect wood, coal, oil, wind,tides and so on to the present direct utilization of solar energy.The technologyof development and utilization of energy are rapidly growing in recent years. At the same time, the solarenergy as an inexhaustible source of green energy is one of the best ways to solve the current energy crisis.the world’s major economies are putting in a lot of manpower、material and financial resources to promotesolar energy technology innovation. Currently, the most popular solar energy research is the developmentand utilization of dye-sensitized solar cells（Dye–Sensitized Solar Cell, DSSC）.DSSC is a new type of thesolar cell. Because of its simple fabrication procedure, low cost, better stability and clean energy, DSSC hasarouse world researchs and application prospect. In this paper, CuO/TiO₂nanotube arrays/Ti-basedcomposite films were fabricated by direct current electro-deposition with or without ultrasound. Themorphology and the structure of CuO/TiO₂nanotube arrays/Ti-based composite films were characterizedrespectively by means of SEM and XRD. The effects of electroplating process parameters （current density）and ultrasound on the composite films morphology were investigated. At the same time, the opticalproperties of dye-sensitized solar cells composed of composite film electrode were studied through thesteady-state photocurrent technique, and getting a photoelectric conversion efficiency of5.39%.1. TiO₂nanotube arrays were successfuiil fabricated by andization method on a pure titanium sheet. Theoptimal reaction conditions were as follows:25V for oxidation potential,20minutes for reaction time and0.5wt%for HF electrolytes concentration. The results of SEM measurements showed that the innerdiameter was about120nm, the length450nm.2. TiO₂nanotube arrays were successfully used as photoelectrodes and the platinum film as the anodeelectrode to build DSSC. The concentration of3.28/L CuSO₄dissolved in water were used as theelectrolyte, under room temperature continuous magnetic stirring, Cu/TiO₂nanotube arrays/Ti-basedcomposite films of various Cu content were prepared by adjusting the applied current density （1Am/cm²,3Am/cm²,6Am/cm²,12Am/cm²）. Then CuO/TiO₂nanotube arrays/Ti-based composite films were obtained after the composite film was constant temperature watering bath. CuO/TiO₂nanotube arrays/Ti-basedcomposite films/dye electrode was fabricated by immersing the composite films into dye N719solution（5×5-5molL-1）for24h.The Pt coated FTO as counter electrode was prepared by thermaldecomposition method. The cell was assembled by dropping an electrolyte solution into the space betweenthe ordinary electrochemical deposition CuO/TiO₂nanotube arrays/Ti-based composite films/dye electodeand the counter electrode Studying its optical and electrical properties by scanning electronmicroscopy（SEM）, X-ray diffraction（XRD） and steady-state light response, we drawwed the bestpreparation process of the ordinary current electrochemical deposition:the applied current density3Am/cm²、5min（Note: In this study, the copper deposition time are5min）.SEM image analysis showed that somecopper oxide had covered the surface of the nanotubes in the process parameters, but we can see the pipewas not sealed; XRD analysis shows the characteristic peaks of copper oxide oxidation are more obvious.the phenomenon shows the match of copper and titanium dioxide achieve the best under ordinaryelectrochemical deposition in this process condition; the best optical and electrical properties through thesteady-state response testing is: open circuit voltage of0.664V, short-circuit current of9.00Am/cm², fillfactor of0.512, conversion efficiency of3.06%.3. Process of ultrasound assisted electrochemical deposition electrode preparation and cell assembly isbasically the same to the ordinary direct current electrochemical deposition CuO/TiO₂nanotubearrays/Ti-based composite films/dye electrode. But the entire experimental setup is put in the ultrasoniccleaning machine in the process of electrode preparation. SEM image can be seen the surface of the copperoxide nanotube arrays does not have a clustered phenomenon, but the internal nanotubes is filled with thestate of small particles,thus increasing a real and effective surface area of the copper oxide and titaniumdioxide. XRD analysis shows that the oxidationcopper appeared in the new diffraction peak（002）.at thesame time,the ultrasound assisted diffraction peaks are stronger than that of the copper oxide under theconditions of ordinary electrodeposition. The best optical and electrical properties were gotten through thesteady-state light response testing: open circuit voltage of0.6884V, short-current of15.50Am/cm², fillfactor of0.505, the conversion efficiency is further from3.06%to5.39%.