A detailed investigation on the performance of dye-sensitized solar cells based on reduced graphene oxide-doped TiO2 photoanode

Abstract

The sintered TiO 2 nanofilms were immersed in the aqueous solution of graphite oxide and then were thermally reduced to reduced graphene oxide (RGO), resulting in RGO-doped TiO 2 photoanodes employed in the dye-sensitized solar cells (DSSCs). This preparation method for the reduced graphene oxide-TiO 2 (RGO-TiO 2 ) photoanode could avoid the loss of RGO during the sintering process. The presence of RGO in the photoanodes was confirmed using Raman analysis, scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectrometer. The amount of RGO in photoanode was obtained by thermo-gravimetric analysis. Other techniques such as X-ray diffraction, Brunauer-Emmett-Teller, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the composite materials of RGO-TiO 2 . The J-V measurement of RGO-TiO 2 -based DSSCs showed that the best photoelectric conversion efficiency (g) of 6.85% is 11.7% higher than that of the pure TiO 2 (P25-TiO 2 )-based DSSCs. It was shown that RGO in the photoanode could facilitate the phase transition in TiO 2 crystals (from anatase to rutile) resulting in the mixed crystals in the photoanodes. The existence of RGO and mixed-crystal structure of TiO 2 changed the electronic transmission pathway, reduced the recombination rate of electron-hole pairs, and thus improved the g of DSSCs.

Optimizing the Performance of the Meso-Scale Continuous-Flow Photoreactor for Efficient Photocatalytic CO2 Reduction with Water Over Pt/TiO2/RGO Composites

“…Also, the percentage of the rutile phase in 0.3 wt.% PTG1 composite was slightly increased after the introduction of RGO and Pt NPs compared with T1. The same observation of the anatase transformation to rutile was previously reported during other metals loading and the introduction of RGO on TiO 2 surface especially with the temperature elevation such as in this case with the hydrothermal reaction [23][24][25][26]. While in the case of 0.3 wt.% PTG2 composite the (anatase: rutile) ratio was maintained at the same value as T2.…”

Titanium dioxide/agglomerated-free reduced graphene oxide hybrid photoanode film for dye-sensitized solar cells photovoltaic performance improvement

“…The most intense peak at 144 cm -1 and the small peak at 198 cm -1 relates to the E g mode. The two other peaks are 399 cm -1 (B 1g ) and 518 cm -1 (A 1g ,B 1g ), which confirms the formation of crystalline TiO 2 [35]. Furthermore, when TC14-rGO was sprayed on the ann TiO 2 NRs-NFs sample, three peaks of Raman active modes were blueshifted to lower wavelengths (144, 444, and 610 cm -1 ) (Figure 4 The micro-Raman spectrum of the TC14-rGO_MWCNTs/Pt CE thin film is presented in Figure 4 (c).…”

“…This is believed to reduce the internal resistance and thus grant an advantage for faster electron transport through NPs before reaching the TiO 2 NRs-NFs layer and the TiO 2 NRs-NFs/TC14-rGO hybrid bottom layer. However, the drawback of applying rGO on TiO 2 also damages TiO 2 structure [35]. This is evidenced by lower J sc (3.275 mA/cm 2 ) and V oc values (0.747 V), as compared to ann TiO 2 NRs-NFs/TiO 2 NPs (see Table 2).…”

“…Besides post-annealing treatment, the hybridization of TiO 2 nanostructures with carbonaceous material, such as carbon nanotubes (CNTs), graphene, graphene oxide (GO), or reduced GO (rGO) was also done in order to improve TiO 2 electrical properties [32][33][34][35][36][37][38]. This was due to the high conductivity of the carbonaceous material, which increases the electron transfer through TiO 2 , decreases the electron recombination, and yields higher short circuit current density (J sc ).…”

“…A higher η of 7.52% was achieved by Zhao et al [38] with a TiO 2 -rGO nanocomposite via a one-step hydrothermal method as compared to a pure film of TiO 2 NPs (6.39%). Meanwhile, Liu et al [35] achieved 6.85% efficiency when immersing the prepared TiO 2 NPs in the GO solution and then reducing them via thermal reduction process. However, they also found that less dye adsorption occurred in the sample with excess rGO.…”