Effect of graphene and Au@SiO₂ core–shell nano-composite on photoelectrochemical performance of dye-sensitized solar cells based on N-doped titania nanotubes

Abstract

We have investigated the role of graphene and Au@SiO 2 core-shell nano-composite (NC), on the performance of dye-sensitized solar cells (DSSC) based on nitrogen doped TiO 2 nanotubes (N-TNTs) as photoanodes. The N-TNTs were synthesized by an environmentally-friendly solvothermal method. The photoelectrochemical performance of DSSCs with N-TNTs improved compared to undoped TNTs; due to extended absorption in the visible part of the solar spectrum. An improved open circuit voltage was also observed with N-TNTs due to a change in the TiO 2 Fermi energy level with increased electron density. After that, we investigated DSSC performance using graphene in N-TNTs with varying concentration from 0.2 to 1.0 wt%. With an optimal concentration of graphene (0.6 wt%), we have achieved 6.33% energy conversion efficiency, which is $47.5% enhancement in performance compared to pure N-TNTs. The enhanced device performance with graphene is mainly due to better dye loading, improved electron transport and charge collection process. To further boost the conversion efficiency of the DSSC based on graphene/N-TNTs NC, we introduced Au@SiO 2 core-shell nanoparticles (NPs) of different concentration into the device structure. Finally, we are able to fabricate a DSSC having an energy conversion efficiency of 7.01% with 1.8% (w/w) of Au@SiO 2 NPs, due to an improved excitation of dye molecules by generated strong near-fields around the Au NPs along with incident light far-fields.Scheme 1 Schematic diagramme of DSSC fabricated using N-TNTs mixed with graphene and Au@SiO 2 core-shell NPs.84424 | RSC Adv., 2015, 5, 84423-84431This journal is

Enhancement of Y123 dye-sensitized solar cell performance using plasmonic gold nanorods

“…This was clearly explained in our previous studies by employing Ag nanowires and Au@SiO 2 NPs in DSSCs. 19,30 It was reported that excess Au NRs/Au NPs can act as self-recombination centres for excited electrons at the TiO 2 interface, and an enhanced light absorption by these Au NRs/Au NPs can transform part of the incident solar light into heat (parasitic absorption). 31,32 In addition, we have also evaluated the LSPR effect of the Au NPs to compare it with that of the Au NRs.…”

“…[15][16][17] Previously, we have also explored the LSPR effects of Ag nanocubes and Au@SiO 2 core-shell NPs on DSSCs based on graphene/TiO 2 nanotube composites, and obtained a significant improvement in the photocurrent and PCE of the DSSCs. 18,19 With Au/Ag nanorods (NRs), one can generate the LSPR modes in a unique way due to the transverse and longitudinal surface plasmon oscillation modes in a nanorod along the short and long axes, respectively, and the longitudinal modes can be tuned easily from the visible to the near IR region by varying the aspect ratio of the nanorods. 20,21 Here, in this study, we have explored the effects of Au NRs on the performance of organic Y123 DSSCs, and also compared the device performance to that obtained with Au NPs.…”

Three-dimensional graphene networks and reduced graphene oxide nanosheets co-modified dye-sensitized solar cells

“…Graphene modied dye sensitized solar cells (DSSCs) have attracted increasing attention because of their high photovoltaic performances. [1][2][3][4][5][6] The large BET area and the high electron mobility of graphene in theory cause it to be a promising modier to enhance the photovoltaic performance of the resulting photoanode and resulting devices. Gao et al reported that the power conversion efficiency (h) increases from 2.69% to 4.28% aer adding 0.5 wt% reduced graphene oxide (RGO) nanosheets.…”

Fence Constructed at a Semiconductor/Electrolyte Interface Improving the Electron Collection Efficiency of the Photoelectrode for a Dye-Sensitized Solar Cell

“…However, metal nanoparticles directly incorporated into TiO 2 nanocrystalline films are exposed to an iodide/triiodie electrolyte, which results in charge recombination and corrosion. − For most of the previous efforts, core–shell structures, such as Au@SiO 2 , , Ag@SiO 2 , , Au@TiO 2 , and Ag@TiO 2 , − have been designed to prevent metal nanoparticles from the electrolyte. However, the shell of SiO 2 could induce the loss of photogenerated carriers owing to the insulating properties of SiO 2 . , The shell of TiO 2 with electron-transport properties as the space isolation layer between the dyes and metal nanoparticles weakens the LSPR enhancement .…”