ABSTRACT
The surface structure and electrical properties of titanium-doped indium oxide (ITiO) films prepared by RF magnetron sputtering were investigated. The doping concentration of TiO2 in the In2O3 target was changed from 1.0 wt.% to 10.0 wt.% with increments of 1.0 wt.%. At a Ti content of 5.0 wt.%, the optimum growth conditions were achieved. The finest value of hall mobility, carrier concentration, and resistivity of the deposited film reached 47.03 cm2Ns, 1.148 x 10(21) cm-3 and 1.14 x 10(-4) Ωcm, respectively. Then the transmittance was achieved up to 82% at 570 nm. The peaks of the XRD spectra became more intense and sharp as the Ti concentration increased up to 2.5 wt.% but a higher Ti content of 10.0 wt.% retarded a growth of In2O3 grains. The surface roughness of the films by examination of surface morphology using AFM also rose with increase of Ti doping concentration.
ABSTRACT
Nanoporous Ti metal film electrodes for use as photoanodes in dye-sensitized solar cells (DSSCs) were deposited directly on the nanoporous TiO2 layer using the two-step RF magnetron sputtering technique. The Ti film electrode replaces the transparent conducting oxide (TCO) layer. The effect of substrate heating during the deposition of the Ti film was studied to improve the porosity and columnar array of the film pores and the resulting cell efficiency. The porous Ti layer (-41 microm) with low sheet resistance (-1.7 omega/sq) was obtained by deposition at 250 degrees C. The porous Ti layer collects electrons from the TiO2 layer and allows the diffusion of I-/I3(-) through the holes. The DSSC efficiency (eta) using porous Ti layers with highly columnar structures was measured with the highest conversion efficiency of -5.77%; the other photovoltaic properties were ff: 0.76, V(oc): 0.72 V, and J(sc): 10.6 mA/cm2.
ABSTRACT
Transparent conductive In(2-x)Sn(x)O3 (ITO) and In(2-x)Ti(x)O3 (ITiO) films were prepared via RF magnetron sputtering on soda-lime glass substrates at 300 degrees C and investigated with respect to their photoelectric conversion performance compared with the commercial F:SnO2 (FTO) glass. The near infrared ray transmittance of ITiO was highest for wavelengths over 1000 nm compared with those of ITO and FTO. Photoelectrochemical cells (PECs) were fabricated using ITiO film, ITO film, and FTO glass. The photoelectric conversion efficiency (eta) of the PECs samples using ITiO was 5.64%, whereas 2.73% was obtained from the PEC samples with ITO, both at 100 mW/cm2 light intensity. The impedance measurement was also used to explain the electrochemical performance of the PECs with various TCO glasses.
ABSTRACT
Nanoporous Ti-metal film electrode was fabricated by radio frequency (rf) magnetron sputtering technique on nanoporous TiO2 layer prepared by sol-gel combustion method and investigated with respect to its photo-anode properties of TCO-less DSCs. The porous Ti layer (approximately 1 microm) with low sheet resistance (approximately 17 Omega/sq.) can collect electrons from the TiO2 layer and allows the ionic diffusion of I(-)/I(3-) through the hole. The porous Ti layer with highly ordered columnar structure prepared by 8 mTorr sputtering shows the good impedance characteristics. The efficiency of prepared TCO-less DSCs sample is about 4.83% (ff: 0.6, Voc: 0.65 V, Jsc: 11.2 mA/cm2).
