Plasmon Enhanced Photovoltaic Performance in TiO₂-Graphene Oxide Composite Based Dye-Sensitized Solar Cells

Abstract

Dye sensitized solar cells (DSSCs) have engendered great research interest with promising potentials in solar cell technology for their high power conversion efficiencies. In this study, we report a plasmon enhanced graphene oxide (GO)-based TiO 2 -GO-Au composite photo-anode toward the improved performance in our DSSCs. The structural and morphological properties of as synthesized GO and TiO 2 -GO-Au composites were investigated using Raman spectroscopy and ultra-high resolution transmission electron microscope (UHRTEM). Photovoltaic performances of DSSC containing TiO 2 -GO-Au composite photoanodes were studied on keeping the constant GO concentration (5 μL) and by varying the concentration of Au-nanoparticles (NP) [1, 3, 5 μL]. A systematic increment in the short circuit current density (J SC ) was noticed while incorporating more Au NP to the photoanode probably due to the increased light absorption, higher optical path of absorbed light and faster electron transfer as a combined effect of GO and Au NP. Thus, a significant enhancement in the overall photovoltaic performance was observed in DSSCs with TiO 2 -GO-Au composite photoanode. Dye sensitized solar cells (DSSCs) have gained increasing attention since Grätzel et al. reported DSSC based on photoanodes consisting of mesoporous titania (TiO 2 ) decorated with the photosensitizer dye molecules followed by a photo-electrochemical process. 1-3Since last decade, plenty of research has been carried out to enhance photo-conversion efficiencies (PCE) by manipulating the architecture on requiring organic and inorganic structures and interfaces. 4,5 Several approaches have been followed to improve light absorption and better collection of photo-generated charge carriers by including metal nanoparticles, 6-8 modifying dye molecules 9,10 or altering surface morphology and interfaces.11,12 However, morphological and dye modifications may lead to adverse effect on the dye adsorption and energy band structure of the photo-sensitizer relative to semiconductor.13 Therefore, a more efficient way to improve charge generation and collection is required without affecting other properties. Surface plasmons have been considered an effective way to increase light absorption properties and light trapping capabilities which significantly improves photogeneration of charge carriers into semiconductor layer. [13][14][15] Surface plasmons are induced by the oscillation of conduction electrons with the electric field of light when metallic nanoparticles (i.e., Au, Ag, and Al etc.) are smaller than wavelength of exciting light. Thus, an enhanced electromagnetic field is observed near to the surface. Addition of metallic nanoparticles for localized surface plasmons to photo-anode is beneficial in improving light absorption as well as charge collection by means of multiplying virtual physical thickness of semiconductor layer. 16 In recent years, addition of metallic nanoparticles (such as Au, Ag) to DSSCs has gained much attention due to significant increase in power efficiency. 17,18 O...

Photovoltaic Effect in ITO/rGO/BFO/Au Heterostructures

“…Graphene oxide (GO) was synthesized from natural graphite powder using modified Hummer's method [18,20]. GO dispersion of concentration 0.1 mg/ml in deionized water was sonicated for 6 hours.…”

“…Therefore, we employed a reduced graphene oxide (rGO) as a semiconducting layer instead of ZnO. Insulating graphene oxide (GO) has also been used for fastening charge transport into dye sensitized solar cells as an electrode material [20]. Insulating GO can be made n-type semiconductor by specific reduction procedure [21].…”

Efficient charge collection of photoanodes and light absorption of photosensitizers: A review

“…In addition to Wei et al's report, the 3DGNs contribute a rapid transport network for the excited electrons and at the same time the RGO nanosheets enhance the interface electron transport between graphene and TiO 2 . Another interesting study was done by Agarwal et al using TiO 2 ‐GO‐Au composite photoanode which take the beneficiaries of both GO and Au‐nanoparticles 105 . This anode have the advantages such as enhanced absorption of light, elevated optical path of absorbed light and rapid electron transfer reached to augmented charge generation, transfer and collection ending up with improved efficiency.…”

“…Another interesting study was done by Agarwal et al using TiO 2 -GO-Au composite photoanode which take the beneficiaries of both GO and Au-nanoparticles. 105 This anode have the advantages such as enhanced absorption of light, elevated optical path of absorbed light and rapid electron transfer reached to augmented charge generation, transfer and collection ending up with improved efficiency. The graphene incorporated not only with TiO 2 but also with SnO 2 and ZnO photoanodes.…”

Microwave-Assisted Hydrothermal Synthesis of Fe-Doped TiO2 Photoanode for Photocatalytic Hydrogen Evolution

“…However, high concentrations of dopants may hinder the effectiveness of photoelectric conversion by interfering with the surface's carrier transfer mechanism. Additionally, by doping in the suitable element, the electronic structure may be optimized to allow for precise regulation of the band of the wavelength of the desired electromagnetic wave, 19,20 Therefore, elemental doping is a viable option that can solve the aforementioned problems, but finding the right element and optimal concentration is crucial. Metals like Cu, Fe, and Ni [21][22][23] noble metals like Au, Ag, and Pd [24][25][26] and anions like N, C, and S [27][28][29] are often cited as examples of suitable doping elements.…”