Controllable Synthesis Of TiO₂ Nanotube Arrays And Its Application In Dye Sensitized Solar Cells

TiO2 nanomaterials have been extensively studied for its applications in photocatalytic degradation,gas sensor,and have been attracted a widespread applications of photovoltaic devices due to its advantages in synthetic convenient,low cost,environment friendly and excellent physical and chemical properties.Compared with different morphologies of TiO2 nano-materials,One dimension TiO2 nanotube arrays(TNTAs)possess attractive properties such as greater specific surface area,highly ordered structure and a speed path for the electron transport which make it the best candidate for the hottest dye-sensitized solar cells research worldwide.In this paper,highly ordered arrangement TiO2 nanotube arrays have been prepared via the anodic oxidation process,the anodic oxidation process was explored to realize the controllable preparation of TiO2 nanotube arrays,the relationship between TiO2 nanotube morphology characteristics and the anodic oxidation process parameters were analyzed,the growth mechanism of nanotube arrays were expounded,and further researches based on the nanotube arrays applied in dye-sensitized solar cells were studied.The main experimental results are as follows:1.The controllable synthesis of TiO2 nanotube arrays.Two-step anodic oxidation method has been used in the preparation of highly ordered TiO2 nanotube arrays,combined with field emission scanning electron microscopy(FESEM)and current-time monitoring software derived from direct current power supply,the system is studied under the condition of different oxidation time,oxidation voltage,and oxidation temperature.The formation process of anodic oxidation of TiO2 nanotubes was revealed by the analysis of tube morphology and the change of the current-time curve.It was found that the oxidation voltage not only played a key role in controlling nanotube diameter,wall thickness and nanotube spacing distance,but also presented a linear relationship with these parameters above.At the same time,oxidation temperature has showed a main influence in tube wall thickness.Thus according to the different oxidation voltage and oxidation temperature,the microstructure parameters of TiO2 nanotube arrays(including nanotube spacing distance,nanotube diameter,wall thickness,etc.)can be controllable designed,so the controllable synthesis of TiO2 nanotube arrays can be achieved.2.The study of dye sensitized solar cell based on TiO2 nanotube arrays.Prior to fabricating dye-sensitized solar cells,the TiO2 nanotube arrays was exfoliated and transferred to the transparent conductive glass(FTO)after the anodic oxidation.First,we designed different annealing temperatures,combined with X-ray diffraction pattern and performance characterization and preparation of solar cell.To get well crystalized TiO2 nanotube arrays,TiO2 nanotube arrays annealed at different temperature,vary from 450? to 600?,so as to explore the optimal heating condition for the solar cells.Among which,we found that TiO2 nanotube arrays were annealed at 500? for 30min,the maximum photoelectric conversion efficiency of dye-sensitized solar cells reached 3.72%;Secondly,Different concentrations of TiCl4 solution were used to decorate the surface of TiO2 nanotube arrays,which will increase the specific surface area,ultimately to enhance the conversion efficiency of the dye-sensitized solar cell.The results show that when the TiCl4 solution concentration is 0.1 M,the current density was 11.89 mA/cm2,and the photoelectric conversion efficiency reached 4.46%,compared to the solar cell without TiCl4 modification,current density and photoelectric conversion efficiency are improved by 36.7%and 36.7%,respectively.