Electrospun Copper Doped Titania Nanofibers for Dye-Sensitized Solar Cells Photoanode /

Abstract

Nanomaterials for photovoltaic have gained a lot of attention in the past few years in the arena of energy. Titania (TiO2) is an important material having found its use in many technological applications. Due to its large surface-to-volume ratio, TiO2 nanofibers (NFs) are drawing increased attention in 3rd generation of photovoltaic solar cells such as DSSC. The electro-optical response of TiO2 can be tuned by metal doping and structural control at the nano level. In this research, NFs of copper (Cu) doped Titania (TiO2) were fabricated by using electrospinning. To get Cu doped TiO2 NFs the calcination and annealing were performed in the air at 500 C for 2 hours. The Energy-Dispersive X-ray Spectroscopy (EDS) results confirmed the doping of copper inside the titania after calcination. Scanning electron microscopy (SEM) results show NFs of varying diameters mostly in the 80 nm to 200 nm regime. SEM of the post-annealed samples shows relatively rougher fibers of reduced size compared to the uncalcined samples which are due to the evaporation of PVP and solvents. The increase in roughness and reduction in the NFs diameter means an increase in the overall surface area and more efficient charge transport as Hall’s effect results depicted that after doping of copper in nanofibers, the conductivity of the nanofibers improved by 2 times as compared to undoped nanofibers of titania. Moreover, Ultraviolet-Visible Spectroscopy (UV-Vis) showed that 1 % Cu doping decreased the bandgap and the absorption of the spectrum shifted more towards the visible region of the spectrum. The IV characteristic measurement was performed, and it gave the efficiency of the prepared solar cell equal to 0.0114 % with Open circuit voltage (VOC) equal to 0.66 V and short circuit current (ISC) equal to 0.03 mA. The increase in the VOC is due to the wide bandgap of semiconductor and decreased diameter of nanofibers. The lower value of the ISC is the result of Cu/electrolyte reaction and low electron injection of Nanofibrous Cu doped TiO2 photoanode.