Preparation Of Films With Titanium Dioxide Nanomaterials And Their Application In Organic-inorganic Hybrid Solar Cells

With the development of science and technology, and the ascension of energydemands, solar cells have attracted extensive research and attention, and alsodeveloped rapidly. Organic-inorganic hybrid solar cells show great applicaitonpotential because of their utilization of advantages which both organic andinorganic semiconductors possess. Organic-inorganic hybrid semiconductors havethe characteristics of inorganic semiconductors of the high carrier mobility, highstability and high mechanical strength, and also the chatacteristics of organicsemiconductors of the structure diversity, high solar spectrum absorption rate, easyprocess and flexibility. Therefore this subject researching on hybrid solar cells hasimportant theoretical significance and potential application values. This subjectresearched from the aspects of preparation of titanium dioxide nanomaterials andphotovoltaic performance of hybrid solar cells using the self-synthetic TiO₂nanomaterials.Firstly, electrospinning method was employed to prepare titanium dioxide（TiO₂） nanofiber arrays and sol-gel method was adopted to prepare TiO₂compactfilms with nanoparticles. Scanning electron microscopy analysis showed that thenanofibers diameter and uniformity are influenced by the composition andconcentration of the spinning solution. When the spinning solution is made up of500mg polyvinylpyrrolidone （PVP） and0.3ml tetrabutyl titanate （Ti（OC4H9）4）, themorphology of nanofibers is the best. Compact films prepared by sol-gel methodare influenced by acidic or alkaline catalysts, acidic conditions are better for themorphology of compact films.Secondly, by meansurement of X-ray diffraction （XRD）, Raman, infrared andX-ray photoelectron spectroscopy （XPS）, the content and phase structure of TiO₂were analyzed. The analysis of X-ray diffraction and Raman spectrum showed thatdifferent preparation methods and holding time of heat treatment have greatinfluences on the phase structure of TiO₂. With the increase of holding time, TiO₂prepared from electrospinning method is mixed phase structures of anatase andrutile, while TiO₂prepared from sol-gel method is still pure anatase structure. Theanalysis of XPS and infrared spectrum showed that TiO₂prepared fromelectrospinning method is doped with carbon into the TiO₂lattices.Finally, making the self-synthetic horizontal multilayer of TiO₂nanofiberarrays blended with conjugated polymer, then the ordered heterojunctions of hybridsolar cells were prepared. The prepared devices were tested to research from thecurrent density-voltage （J-V） characteristic curves. It was concluded that device performance is certain influenced by the modification of active layer interfaces,TiO₂heat treatment holding time, TiO₂nanofibers prepared from electrospinningand the thickness of TiO₂films prepared from sol-gel method. Integratingorganization and structure analysis and also photoelectric performance test, theoptimal device structure was determined that ITO/compact-TiO₂（100nm）/porous-TiO₂fiber arrays （calcined3h）/Z907/P3HT/MoO3/Al, this device gets0.42%of thephotoelectric conversion efficiency （PCE） ultimately. This topic provides animportant reference basis for the preparation of hybrid solar cells with other kindsof conjugated polymers, which is expected to get a higher device efficiency.