Research Of Dye-sensitised Solar Cells With ZnO Nanorod Array Film As Photoanode

In this paper we comprehensively discusses the research and development of solar cells, sum up out the advantage of dye-sensitised solar cells, as well as the problems existing in the research process. Dye sensitized solar cell(DSSC) is a new kind of thin film solar cells, and its preparation technology is simple, the rich raw material sources, preparation of environment friendly, battery photoelectric performance is stable, and low cost. And Zn O with its rich raw materials, cheap, non-toxic, transparent conductive characteristics of becoming a hotspot in research of the solar cell photoanode material.Zn O films seed layer were prepared by the sol-gel method using ethylene glycol methyl ether as solvent, zinc acetate as the former body, diethanolamine as stabilizer, polyethylene glycol(PEG) as the surfactant. After drying, high temperature calcination, finally got uniform, transparent Zn O films. Besides we got the following excellent process parameters about preparation of film performance, including sol concentration, liquid of sol drying temperature and time, calcined temperature. Adopting low temperature growth method, solution with zinc nitrate and six methylene amine liquid mixture for growth, then prepared Zn O nanorod array films on the Zn O seed layer. After that we characterized the Zn O powder and nanorods array films with method of X-ray diffraction and characterized the Zn O films and nanorods array films with scanning electron microscope, electron paramagnetic resonance instrument, ultraviolet-visible absorption spectra and made testing of photovoltaic performance of assembled DSSC with the solar I-V test systems. The research shows that:(1) The best preparation conditions of Zn O nanorod array films was preparation of low-temperature solution growth method, with mixture of zinc nitrate and six four methylene amine solution for growth, prepared Zn O nanorod array films on the Zn O seed layer, the growth liquid concentration was 0.025 mol/L, Zn O films should be upright, the preparation of Zn O seed layer should add PEG as well as the growth time was 4.5 h.(2) The XRD results showed that zinc oxide nano powder was six-party wurtzite structure, and crystalline was good, without impurity peak; Zn O nanorod array film(FTO/ZNA electrode) sample’s diffraction peak of every diffraction plane match the standard wurtzite structure of zinc oxide, belongs to the hexagonal wurtzite structure. The diffraction peak shape was narrow and sharp, with a few caused by material of conductive glass FTO diffraction peak, no other impurity peak, it indicated that by low temperature solution prepared FTO/ZNA electrode was high purity. FTO/ZNA electrode grain size(48.6 nm) was greater than zinc oxide powder(31 nm); Its(002) crystal plane of preferred orientation i(002) = 0.846 was also better than powder i(002) = 0.214.The vast majority of Zn O nanorods was along the(002) crystal growth, namely along the c axis preferred orientation of epitaxial growth.(3) The SEM results showed that surfactants PEG can prevent nano zinc oxide film in the calcining process reunited nanoparticles and cracks by annealing; Different growth time, concentration of liquid, the way placed basal all affect the growth of Zn O nanorods arrays. By comparison with the result of the experiment: The Zn O nanorods arrange film relatively regular really tired, the size distribution is relatively uniform, the average diameter of about 100 nm while FTO conductive glass upright in 95℃ temperature while the concentration is 0.025 mol/L growth time was 4.5 h.(4) EPR results showed that Zn O seed layer and Zn O nanorod array films had strong paramagnetic absorption signal at g = 1.926, the position of the EPR signal peak was near with Zn O powder, so the signal may be the signal generated by Zn-H that in the preparation process, it can be used as FTO/ZNA electrode and Zn O seed layer of EPR characteristic signal qualitative judgment FTO/ZNA electrode on the number of free electrons more than Zn O seed layer, made it easier to transmit in the circuit.(5) The UV-Vis spectra results showed that Zn O seed layer and FTO/ZNA electrodes have a strong absorbent in ultraviolet band, and the FTO/ZNA electrode in the absorption of ultraviolet light intensity is stronger than Zn O seed layer. After being zinc porphyrin dye sensitization FTO/ZNA electrode represents the absorption band in the visible light range and had strong absorption peaks at 426 nm, this was mainly caused by zinc porphyrin dyes to visible light absorption, showed the zinc porphyrin dyes to FTO/ZNA electrode sensitized produced a good effect.(6) Using Zn TPP dye sensitization FTO/ZNA electrodes, and assembled DSSC sensitizing electrode,made testing of the photoelectric performance of the DSSC by I-V curve system, the testing results was that the open circuit voltage was 592 mv, short circuit current was 4.1498 m A, fill factor is 0.51, the maximum output power was 1342.097 mW, photovoltaic conversion efficiency was 1.67%.