Preparation Of Transparent Conductive Cellulose Film And Application Of Dye-Sensitized Solar Cells

Dye-sensitized solar cells,a new type of electronic devices,can convert solar energy into electrical energy,and are currently being used as one of the clean energy sources.The transparent conductive substrate as the core of electronic devices decides the performance of dye-sensitized solar cells.Nowdays,cellulose has been regarded as a new generation of"green" electronic devices because of its abundant resource,low cost,biodegradable,winding performance and other advantages,and is expected to replace plastic,glass and other substrates to prepare a new generation of "green" electronic devices.In this work,transparent cellulose film was prepared based on the NMMO(N-methyl morpholine-N-oxide)film-forming process.Conductive transparent films(Ag/cellulose film and ITO/cellulose film)were prepared by using sputtering technology;furthermore,the dye-sensitized solar cells were prepared by using the conductive cellulose film as the substrate.The effects of cellulose concentration,dissolution time and dissolution temperature on the properties of cellulose films were evaluated,and the preparation process was optimized.The results showed that cellulose film with high light transmittance 85.4%and mechanical strength 36.9 MPa could be prepared by the optimum condition of cellulose concentration of 7%,dissolution temperature of 110 ℃ and temperature of 25 ℃.In this case,the cellulose film could keep a good optical properties(light transmittance 78.9%)and thermal stability under higher temperature(210℃).The further study showed that the film has a certain resistance to acid and alkali.The Ag/cellulose composite films were prepared by using high vacuum magnetron sputtering technique and the process was studied.The results showed that the parameters time,power and gas flow could affect the light transmittance and block resistance of the condutive film.Under the condition of the sputtering time 45 s,sputtering power 50W,gas flow rate 50 sccm,the Ag/cellulose film could be prepared with a good electrical conductivity for block resistance 7.8Ω/□,but with a low visible light transmittance 51.3%,which could not be used as a substrate for dye-sensitized solar cells preparation.From the scanning electron microscope and atomic force microscopy,it can be seen that the Ag/cellulose composite film is formed by covering the surface of the cellulose film with the Ag layer of Ag particles slowly packed into a dense Ag layer.The ITO/cellulose films were prepared by sputtering indium tin oxide(ITO)onto the transparent cellulose film substrate by high vacuum magnetron sputtering technique;while the process was evaluated.The results showed that,by contrast to Ag/cellulose film,the ITO/cellulose film had a low block resistance,good flatness and high light transmittance.Under the condition of sputtering time 3h,sputtering power 110W,sputtering pressure 3Pa,and sputtering temperature 120 ℃,the block resistance of the film could be as low as 10.5Ω/□,and the average light transmittance could be up to 72.8%.By scanning electron microscopy and atomic force microscopy,ITO/cellulose composite film has good compactness and flatness.Furthermore,the properties of the film can satify the demand for preparation of dye-sensitized solar cells.The photoelectro properties of dye-sensitized solar cells were analyzed by using ITO/cellulose conductive film as the photoelectrode and counter electrode of dye-sensitized solar cell.The dye-sensitized solar cell with N79 as dye was constructed.The results show that the photoelectric conversion efficiency of the device is 1.1%,the open circuit voltage is 0.67V,the filling factor is 40.1%,the short circuit current is 4.08mA/cm~2 when the ITO/cellulose conductive film is used as the photocathode,and the ITO/When the conductive film is used as the counter electrode,the photoelectric conversion efficiency of the device is up to 5.2%,the open circuit voltage is up to 0.92V,the filling factor is 59.4%,and the short circuit current is 9.52 mA/cm~2.The use of ITO/cellulose conductive film as a dye-sensitized solar cell electrode,is conducive to reducing the battery within the loss of energy and photogenerated carrier generation,the research method for the development of high-performance dye-sensitized solar cell electrode material A new research method.