• Energy Research

Rapid depletion of fossil fuel leads to increasing energy demand in the near future and it will force us to seek alternative eco-friendly and renewable energy resources. Dye-sensitized solar cells (DSSCs) represent one of the most promising emerging technologies for light-to-electrical energy conversion. Titania is the most widely used photoanode, but its limited performance due to poor interfacial charge transfer and limited optical properties has motivated the quest for modified titania materials to overcome this issue. The emergence of gold–titania nanocomposite materials (Au–TiO2) as a new component to fabricate the DSSCs has opened up new ways to effectively utilize renewable energy sources. This review article mainly focuses on the superior photovoltaic performance of Au–TiO2 nanocomposite materials based photoanode in DSSCs. The review justifies how plasmonic Au influences the visible light absorption, electrons transfer process and solar energy conversion efficiency. Data supporting and confirming the superiority of Au on TiO2 or TiO2 on Au are briefly presented to justify the possibility of electron transfer from dye to conduction band of the TiO2 through Au. This account further highlights the recent developments in these area and points out some specific Au–TiO2 plasmonic nanoarchitectures as photoanode for improved device performance.

Rapid depletion of fossil fuel leads to increasing energy demand in the near future and it will force us to seek alternative eco-friendly and renewable energy resources. Dye-sensitized solar cells (DSSCs) represent one of the most promising emerging technologies for light-to-electrical energy conversion. Titania is the most widely used photoanode, but its limited performance due to poor interfacial charge transfer and limited optical properties has motivated the quest for modified titania materials to overcome this issue. The emergence of gold–titania nanocomposite materials (Au–TiO2) as a new component to fabricate the DSSCs has opened up new ways to effectively utilize renewable energy sources. This review article mainly focuses on the superior photovoltaic performance of Au–TiO2 nanocomposite materials based photoanode in DSSCs. The review justifies how plasmonic Au influences the visible light absorption, electrons transfer process and solar energy conversion efficiency. Data supporting and confirming the superiority of Au on TiO2 or TiO2 on Au are briefly presented to justify the possibility of electron transfer from dye to conduction band of the TiO2 through Au. This account further highlights the recent developments in these area and points out some specific Au–TiO2 plasmonic nanoarchitectures as photoanode for improved device performance.

We report a simple and convenient method for the preparation of Ag/TiO2thin films supported on indium tin oxide, which was achieved by sonochemical deposition of Ag+on aerosol-assisted chemical vapour deposited TiO2thin films. Posttreatment was performed on the film by immersion in HCl. The as-prepared composite film was characterised by X-ray diffraction, ultraviolet-visible absorption spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy. The photoelectrochemical measurements andJ-Vcharacterisation showed approximately fivefold increase in photocurrent density generation and approximately sevenfold enhancement in dye sensitiser solar cell (DSSC) conversion efficiency, which was achieved after modification of the TiO2film with HCl posttreatment and Ag particle deposition. The improved photocurrent density of 933.30 μA/cm2, as well as DSSC power conversion efficiency of 3.63% with high stability, is an indication that the as-synthesised thin film is a potential candidate for solar energy conversion applications.

We report a simple and convenient method for the preparation of Ag/TiO2thin films supported on indium tin oxide, which was achieved by sonochemical deposition of Ag+on aerosol-assisted chemical vapour deposited TiO2thin films. Posttreatment was performed on the film by immersion in HCl. The as-prepared composite film was characterised by X-ray diffraction, ultraviolet-visible absorption spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy. The photoelectrochemical measurements andJ-Vcharacterisation showed approximately fivefold increase in photocurrent density generation and approximately sevenfold enhancement in dye sensitiser solar cell (DSSC) conversion efficiency, which was achieved after modification of the TiO2film with HCl posttreatment and Ag particle deposition. The improved photocurrent density of 933.30 μA/cm2, as well as DSSC power conversion efficiency of 3.63% with high stability, is an indication that the as-synthesised thin film is a potential candidate for solar energy conversion applications.

In this paper the synthesis of self-organized Titania nanotubes (TNTs) by a facile potentiostatic anodization in a glycerol-based electrolyte is reported. The optimized TNTs were subsequently reduced through a cathodic reduction process to enhance its capacitive performance. FESEM and XRD were used to characterize the morphology and crystal structure of the synthesized samples. XPS analysis confirmed the reduction of Ti4+ to Ti3+ ions in the reduced Titania nanotubes (R-TNTs). The tube diameter and separation between the tubes were greatly influenced by the applied voltage. TNTs synthesized at voltage of 30 V for 60 min exhibited 86 nm and 1.1 µm of tube diameter and length, respectively and showed high specific capacitance of 0.33 mF cm−2 at current density of 0.02 mA cm−2. After reduction at 5 V for 30 s, the specific capacitance increased by about seven times (2.28 mF cm−2) at 0.5 mA cm−2 and recorded about 86% capacitance retention after 1000 continuous cycling at 0.2 mA cm−2, as compared to TNTs, retained about 61% at 0.01 mA cm−2. The charge transfer resistance drastically reduced from 6.2 Ω for TNTs to 0.55 Ω for R-TNTs, indicating an improvement in the transfer of electrons and ions across the electrode–electrolyte interface.

In this paper the synthesis of self-organized Titania nanotubes (TNTs) by a facile potentiostatic anodization in a glycerol-based electrolyte is reported. The optimized TNTs were subsequently reduced through a cathodic reduction process to enhance its capacitive performance. FESEM and XRD were used to characterize the morphology and crystal structure of the synthesized samples. XPS analysis confirmed the reduction of Ti4+ to Ti3+ ions in the reduced Titania nanotubes (R-TNTs). The tube diameter and separation between the tubes were greatly influenced by the applied voltage. TNTs synthesized at voltage of 30 V for 60 min exhibited 86 nm and 1.1 µm of tube diameter and length, respectively and showed high specific capacitance of 0.33 mF cm−2 at current density of 0.02 mA cm−2. After reduction at 5 V for 30 s, the specific capacitance increased by about seven times (2.28 mF cm−2) at 0.5 mA cm−2 and recorded about 86% capacitance retention after 1000 continuous cycling at 0.2 mA cm−2, as compared to TNTs, retained about 61% at 0.01 mA cm−2. The charge transfer resistance drastically reduced from 6.2 Ω for TNTs to 0.55 Ω for R-TNTs, indicating an improvement in the transfer of electrons and ions across the electrode–electrolyte interface.

We firstly report on the successful application of a gold nanoparticles deposited nitrogen doped-titania (Au/N-TiO2) nanocomposite as an efficient photoanode for highly efficient dye-sensitized solar cells (DSSC) with the standard photosensitizer, N719 dye. The Au/N-TiO2 nanocomposites with different Au contents are prepared using a simple chemical reduction method and characterized using various analytical techniques. The DSSC assembled with the Au/N-TiO2 modified photoanode demonstrated an enhanced solar-to-electrical energy conversion efficiency of 7.90% compared to the photoanode of a DSSC composed of bare TiO2 (2.55%) under full sunlight illumination (100 mW cm−2, AM 1.5G). This enhanced efficiency is mainly attributed to the doping of N and deposition of Au NPs on the TiO2 surface as a resultant of reduction in the band-gap energy, plasmonic effect improved interfacial charge transfer process and minimized charge recombination. The influence of Au content on the overall energy conversion efficiency is also investigated, and the optimum Au content for N-TiO2 is found to be 10 mM. The enhanced solar energy conversion efficiency demonstrated by the Au/N-TiO2 nanocomposite makes it a promising alternative to conventional photoanode-based DSSCs.

We firstly report on the successful application of a gold nanoparticles deposited nitrogen doped-titania (Au/N-TiO2) nanocomposite as an efficient photoanode for highly efficient dye-sensitized solar cells (DSSC) with the standard photosensitizer, N719 dye. The Au/N-TiO2 nanocomposites with different Au contents are prepared using a simple chemical reduction method and characterized using various analytical techniques. The DSSC assembled with the Au/N-TiO2 modified photoanode demonstrated an enhanced solar-to-electrical energy conversion efficiency of 7.90% compared to the photoanode of a DSSC composed of bare TiO2 (2.55%) under full sunlight illumination (100 mW cm−2, AM 1.5G). This enhanced efficiency is mainly attributed to the doping of N and deposition of Au NPs on the TiO2 surface as a resultant of reduction in the band-gap energy, plasmonic effect improved interfacial charge transfer process and minimized charge recombination. The influence of Au content on the overall energy conversion efficiency is also investigated, and the optimum Au content for N-TiO2 is found to be 10 mM. The enhanced solar energy conversion efficiency demonstrated by the Au/N-TiO2 nanocomposite makes it a promising alternative to conventional photoanode-based DSSCs.