Syudy On The Hybrid Sensitized Solar Cell Based On The One-Dimensional Shell-Core Composite Semiconductors

Narrow bandgap inorganic semiconductor nanocrystals with their excellent light absorption performance and chemical stability have become the alternatives to the traditional dye sensitizer. Meanwhile, the organic/inorganic hybrid photoanodes, with the high carrier transportation ability of the inorganic nano-semiconductor materials and the high absorption coefficient of the organic semiconductor polymer, could provide some new ideas for improving the efficiency of solar cells. In this work, based on the above mentioned two kinds of ideas, a novel three-component one-dimensional shell-core nanoarray structure has been designed and used as photoanode to assemble a novel solar cell sensitized with hybrid composite semiconductors, in which the ZnO rod or nanotube were acted as rapid channel of the photogenerated electrons, the n-type narrow bandgap semiconductors were acted as sensitizers and the p-type polymer semiconductor of P3HT was acted as hole transport material. An electrochemical method was used on the whole preparation process. The absorption properties of the organic and inorganic materials, the energy level matching and interfacial properties between different materials and the transportation rate of the photogenerated carriers in the structure have also been considered. The preparation processes of electrode materials and the performance measurement of the designed electrode and solar cell were studied in detail. The influencing factors of the electrodes preparation, the relationship between the conversion efficiency and the electrode structure were all investigated systematically. The working principle for the designed hybrid sensitizeing solar cell was also discussed. The novel designed nanostructure provides a new train of thought for the development of the solar cells. The main contents and findings are summarized as follows.1. Assisted with the novel additions of PEG-400and EDA, the high ordered ZnO nanorod arrays were fabricated directly on ITO substrates in the Zn(NO3)2solution through a potentiostatic deposition process. The influences of the content of PEG-400and EDA on the morphologies and photoelectrochemical properties of the ZnO seed layer and nanorod arrays were investigated in detail.2. By electrochemical corrosion method, ZnO nanotube array was prepared in the EDA solution (pH%13) using ZnO nanorod array as template. The influence of the electrochemical corrosion time on the morphologies of the ZnO nanotube arrays was investigated. Then, the photoelectrochemical properties of the ZnO nanorod and nanotube array were compared.3. By electrochemical method, CdS nanocrystal shells were deposited into the ZnO nanorod and nanotube array to prepare the1D shell-core CdS/ZnO nanoarrays successfully. The deposition potential was determined using cyclic voltammetry based on the depositeion mechanism. The influence of the CdS deposition time on the morphologies, absorption properties and photovoltaic performance of the1D shell-core CdS/ZnO nanoarrays were investigated. The photovoltaic performances of the semiconductor-sensitized solar cells based on the1D shell-core CdS/ZnO nanorod and nanotube array were compared. The superiority of the double shell sensitization system in the CdS/ZnO shell-core nanotube array was discussed.4. The1D shell-core P3HT/CdS/ZnO nanoarrays were prepared through an electrochemical method and used as the photoanode to assemble a novel solar cell co-sensitized with a p-n hybrid structure. The work principle of the novel designed solar cell was discussed through the study on the photoelectrochemical properties of the electrodes and the photovoltaic performance of the solar cells. A conversion efficiency of1.28%was obtained through the electrode optimization.5. In order to improve the photovoltaic performance of the designed solar cell. Three different photosensitive layers, CdSxSe1-x、CdSe/CdS and CdSe, were chosen to replace the CdS layer. The results indicated that the CdSxSe1-x layer showed the best sensitizing property. An enhanced conversion efficiency up to1.37%was obtained from the new solar cell based on the1D shell-core P3HT/CdSxSe1-x/ZnO nanoarray, which realized the preliminary improvement of the new designed solar cell.