Study On Application Of Carbon Films Prepared By Magnetron Sputtering For Solar Cells

Dye-sensitized solar cells(DSSCs) which developed in1990s have been regarded as anovel thin-film solar cells owing to their low cost materials, high energy conversionefficiency and simple fabrication methods. DSSCs were prepared in nanotechnology byGr tzel and co-workers of Ecole Polytechnique de Lausanne for the fist time and obtained aconversion of7%. Since then, DSSCs became a research focus in community scholars andwas developed rapidly. Counter electrode as an important part of DSSCs mainly involved inthe collection and transport processes of the electronic. However, counter electrode preparedof platinum (Pt) was high cost, carbon materials with the properties of high catalytic activity,good conductivity, stability and low cost have been attracting much attention. Currently,carbon materials as the counter electrode of DSSCs have been achieved a relatively highconversion efficiency of10.04%.In this paper, carbon counter electrode was deposited by bipolar pulse magnetronsputtering using graphite target on the substrate of FTO glasses. In order to choose a betterexperimental condition and process parameter, the effects of sputtering power, substratetemperature, sputtering pressure, nitrogen doping content on carbon bond structure, surfacemorphology, sheet resistance for carbon films were investigated.The experimental results indicated that the carbon film prepared by magnetron sputteringwas amorphous diamond-like carbon. The degree of graphitization raised by heat treatmentand the resistance of carbon film decreased, electrical conductivity increased. The sputteringpower had effect on the surface roughness of carbon film. The transmittance of carbon filmwas determined by the sputtering pressure. Amount of nitrogen doping content alsocontributed to the increasing of the conductive. The optimum condition of the carbon counterelectrode in DSSCs was50W sputtering power,400℃substrate temperature,0.5Pasputtering pressure,30%nitrogen partial pressure. The highest photoelectric conversionefficiency of the cell is1.16%. Compared with other counter electrode materials, such asgraphite counter electrode prepared by screen printing, platinum counter electrode prepared by evaporation, the amorphous diamond-like carbon counter electrode prepared by magnetronsputtering had a low performance on short circuit current density, open circuit voltage, fillfactor and photoelectric conversion efficiency. But it still had a good prospect for the furtherdevelopment and the space of application.