Study of dye sensitized solar cells based on ZnO photoelectrodes deposited by laser ablation and doctor blade methods

Abstract

Dye sensitized solar cells (DSSCs) based on ZnO photoelectrodes deposited by picosecond laser ablation and doctor blade methods are studied. For deposition of ZnO photoelectrodes by laser ablation, a picosecond Nd:YVO4 laser (8ps, 50kHz, 532nm, 0.17J/cm2) was used. Depositions were made starting from a Zn pure target on fluorine doped tin oxide (FTO) substrate, in oxygen atmosphere at 10sccm gas flow rate at room temperature (RT). After deposition, the films were subjected to an annealing treatment at 400°C in oxygen for 2h. For deposition of ZnO photoelectrodes by doctor blade method, ZnO paste using ZnO nanoparticles (MK Impex Corp. 99.9%, 20nm) was prepared. The influence of the ZnO photoelectrodes, prepared by the two different methods, on the performances of the dye sensitized solar cells was investigated.The ZnO photoelectrodes prepared by both methods were investigated from morphostructural point of view. The optimum parameters of the films deposited by laser ablation which to correspond to the best efficiency of the cells were: 450mTorr oxygen pressure, with 5.83μm film thickness, delivering 580mV open circuit voltage (Voc), 1.16mA/cm2 short circuit current density (Jsc), 33% fill factor (FF), 0.22% conversion efficiency (ƞ). Concerning the ZnO photoelectrodes deposited by doctor blade method, almost a double value for ƞ was obtained of 0.43%, 25μm film thickness, 483mV Voc, 2.52mA/cm2 and 36% (FF).