Plasma Treatment Effect on Dye-Sensitized Solar Cell Efficiency of Hydrothermal-Processed TiO2 Nanorods

Abstract

Atmospheric plasma (AP) treatment was carried out on TiO2 nanorods (NRs) that were hydrothermally grown on F-doped SnO2 (FTO)/glass. The effects of AP treatment on the surface of the TiO2 NRs were investigated, where the treatment involved the use of the reactive gases H2, N2, and O2. The surface energy of AP-treated TiO2 NRs was about 1.5 times higher than that of untreated TiO2 NRs (364.3 mJ/m2). After AP treatment, the increase of the peak area ratios of the Ti2O3 and TiO2 peaks in the XPS spectra resulted in a decrease in the number of oxygen vacancies in the TiO2 NRs. The efficiency of a dye-sensitized solar cell (DSSC) based on the N2-plasma-treated TiO2 NRs, which was approximately 1.11%, was about 79% higher than that of a DSSC based on the untreated TiO2 NRs.

Effects of low pressure plasma treatments on DSSCs based on rutile TiO2 array photoanodes

“…3f and h. These structural changes should result from the etching of the unstable chemical states at the rutile grain boundary by plasmas [29]. The much significant morphological changes of OP and NP samples can be attributed to the higher physical etching abilities of oxygen and nitrogen plasmas as reported in previous researches [30]. The negligible morphological change after HP treatment means that hydrogen plasma treatment has milder etching abilities, which is consistent with the report that hydrogen plasma is much weaker than oxygen plasma [31,32].…”

Employing Optical Emission Spectroscopy to Elucidate the Impact of Titanium Dioxide in Plasma-Assisted Catalysis

“…Figure 7a shows high-resolution Ti 2p spectra of an UT TiO 2 substrate and TiO 2 substrates after a 2 min exposure to a 100% CH 4 plasma under several pressure and power conditions. As stated above, binding energies for Ti 2p3/2 and Ti 2p1/2 are present at 458.6 and 464.2 eV, respectively, corresponding to surface titanium in the Ti 4+ oxidation state 35,36 Additionally, contributions from the Ti 3+ binding environment are noted at 457.9 and 462.5 eV for materials treated at p = 200 mTorr and P = 25 W. 35 High-resolution O 1s spectra (Figure 7b) show contributions from lattice bound oxygen at 530.2 eV and adsorbed oxygen species at 532.1 eV for the UT material and after CH 4 plasma exposure. 39,40 The TiO 2 substrates exposed to a CH 4 plasma have an additional peak at 533.3 eV, corresponding to oxygen singly bound to carbon in ethers.…”

“…Representative high-resolution Ti 2p , O 1s , and C 1s XPS spectra prior to and post H 2 plasma exposure ( p = 100 mTorr, P = 150 W, and t = 1 min) are shown in Figure . High-resolution Ti 2p spectra of the UT TiO 2 material (Figure a) show peaks for Ti 2p3/2 and Ti 2p1/2 at binding energies of 458.8 and 464.7 eV, respectively, corresponding to surface titanium in the Ti 4+ oxidation state. , In some cases, Ti 4+ was reduced (i.e., Ti 3+ or Ti 3+ and Ti 2+ binding environments noted in addition to Ti 4+ ) after H 2 plasma exposure, whereas in other cases, the Ti 2p binding environment remained nominally unchanged post H 2 plasma exposure (i.e., only Ti 4+ binding environments present). Reduction of Ti 4+ was not dependent on plasma parameters and was somewhat inconsistent between spots on a single sample and/or different samples produced under the same plasma conditions.…”

Formation Mechanism of Passivation Layer under Air Exposure on TiZrV Non-Evaporable Getter Film

“…30 The full width at half-maximum (fwhm) for each spin−orbit component is the same for Zr 3d; however, for Ti 2p and V 2p, their 2p 1/2 components are much broader than their 2p 3/2 peaks due to the Coster−Kronig effect. 36,37 Furthermore, for Ti 2p, the splitting Δ-values for different materials are Δ oxide = 5.7 eV, 38,39 Δ carbide = 6.0 eV, 38 and Δ metal = 6.0 eV; 40 for V 2p, Δ oxide = 7.4 eV, 41 Δ carbide = 7.7 eV, 42,43 and Δ metal = 7.64 eV; 35 and for Zr 3d, Δ oxide = Δ carbide = Δ metal = 2.43 eV. 35…”