Achieving enhanced DSSC performance by microwave plasma incorporation of carbon into TiO2 photoelectrodes

Abstract

The photoactivity of carbon-incorporated titanium dioxide (TiO 2 ) has been widely reported. This study involves a novel approach to the incorporation of carbon into TiO 2 through the use of microwave plasma processing. The process involved thermally treating printed TiO 2 nanoparticle coatings in a microwave-induced argon-oxygen plasma containing low concentrations of methane. The resulting deposited carbon layer was characterized using XRD, XPS, Raman, UV-VIS, ellipsometry, and optical profilometry. It was found that methane gas had been dissociated in the microwave plasma into carbon species, which were then deposited as a nm-thick layer onto the TiO 2 coatings, most likely in the form of graphite. The photovoltaic performances of both the TiO 2 and the carbon-incorporated TiO 2 were assessed through J-V and IPCE measurements of the N719-sensitized solar cells using the titania as their photoanodes. Up to a 72% improvement in the maximum power density (P d-max ) was observed for the carbonincorporated TiO 2 samples as compared to the TiO 2, onto which no carbon was added. This improvement was found to be mainly associated with an increase in the short-circuit current density (J sc ), but independent from the open-circuit voltage (V oc ), the filter factor (FF), and the level of dye adsorption. Possible contributory factors to the improved performance of the carbonincorporated TiO 2 were the enhanced electron conductivity and electron lifetime, both of which were elucidated through electrochemical impedance spectroscopy (EIS). When the surface layer was examined using XPS, the optimal carbon content on the TiO 2 coating surface was found to be 8.4%, beyond which there was a reduction in the DSSC efficiency.

Surface modification of dye-sensitized solid-state solar cells by atmospheric-pressure plasma jet

“…There are some reports on XPS analysis of TiO 2 surfaces treated by various kinds of plasma, and applied for the plasma etching or plasma-assisted deposition process. 24,34) In this study, excited Ar species and O 2 species generated by an atmospheric-pressure plasma jet mainly contributed to surface modification of the TiO 2 surface. The applied voltage was set at 5.0 kV.…”

“…TiO 2 surface modification by low-pressure plasma treatment has been carried out, and an increase in the solar conversion efficiency has been reported using RF-plasma [20][21][22][23] and vacuum deposition. [24][25][26][27][28][29] Modification methods in atmospheric condition, dielectric barrier discharge (DBD), 30,31) corona discharge, 32) and plasma jet, [33][34][35] have also been reported. By using atmospheric-pressure plasma, there is the advantage that a vacuum device is not required.…”

Impact of carbon-fluorine doped titanium dioxide in the performance of an electrochemical sensing of dopamine and rosebengal sensitized solar cells

“…It is inferred that the Fluorine doping in TiO 2 helps to reduce the charge recombination and increase the charge transfer to the TiO 2 which increase the J sc and η. 54 Both Carbon and Fluorine co-doped TiO 2 based cell show 35% and 38 % improvement in J sc (0.908 mA/cm 2 ) and η (0.147%) respectively. The V oc and FF of the DSSCs are almost same as that of the all other cells.…”

“…Recent attempts have been made to modify the TiO 2 with nanostructured carbonaceous material and Fluorine to enhance the photo activity. [30][31][32] To the best of our knowledge, no reports exist in the study of CFT for DA sensing and photovoltaic energy conversion. In this report, we synthesized the TiO 2 nanoparticles doped with Carbon, Fluorine and Carbon & Fluorine via the solid state method.…”

Surface modification of dye-sensitized solid-state solar cells by plasma jet

“…TiO 2 surface modification by low pressure plasma treatment has been carried out, and an increase of the solar conversion efficiency has been reported using the RF-plasma [13][14][15][16] and vacuum deposition [17][18][19][20][21]. Modification methods in atmospheric condition, dielectric barrier discharge (DBD) [22,23], corona discharge [24], and plasma jet [25][26][27], have been also reported.…”