Enhanced photovoltaic performance of silver@titania plasmonic photoanode in dye-sensitized solar cells

In the present investigation, silver@titania (Ag@TiO2) plasmonic nanocomposite materials with different Ag content were prepared using a simple one-step chemical reduction method and used as a photoanode in high-performance dye-sensitized solar cells. Transmission electron microscopic images revealed the uniform distribution of ultra-small Ag nanoparticles with a particle size range of 2–4 nm on the TiO2 surface. The incorporation of Ag on the TiO2 surface significantly influenced the optical properties in the region of 400–500 nm because of the surface plasmon resonance effect. The dye-sensitized solar cells (DSSCs) assembled with the Ag@TiO2-modified photoanode demonstrated an enhanced solar-to-electrical energy conversion efficiency (4.86%) compared to that of bare TiO2 (2.57%), due to the plasmonic effect of Ag. In addition, the Ag nanoparticles acted as an electron sink, which retarded the charge recombination. The influence of the Ag content on the overall efficiency was also investigated, and the optimum Ag content with TiO2 was found to be 2.5 wt%. The enhanced solar energy conversion efficiency of the Ag@TiO2 nanocomposite makes it a promising alternative to conventional photoanode-based DSSCs

Aerosol assisted chemical vapour deposited (AACVD) of TiO2 thin film as compact layer for dye-sensitised solar cell

Compact TiO2 has been introduced onto the surface of an indium tin oxide glass slide (ITO), using an aerosol-assisted chemical vapour deposition method. This serves as a blocking layer for a dye-sensitised solar cell (DSSC). The thickness of the compact TiO2 could be controlled by deposition time. X-ray diffraction and Raman spectroscopy analyses reveal that the compact TiO2 is made up of mixed anatase and rutile phases. The field emission scanning electron microscopy image displays a pyramidal morphology of the compact TiO2. A layer of P25 paste was then smeared onto the compact TiO2-modified ITO, using the doctor's blade method. A post-treatment procedure was applied to remove the contaminants from the prepared hybrid film, by immersing in a hydrochloric acid solution. The photoelectrochemical measurements and J–V characterisation of the hybrid film show an approximately fourfold increase in photocurrent density generation (114.22 µA/cm2), and approximately 25% enhancement of DSSC conversion efficiency (4.63%), compared to the acid-treated P25 paste alone (3.68%)

Silver/titania nanocomposite-modified photoelectrodes for photoelectrocatalytic methanol oxidation

Silver deposited titania (Ag/TiO2) nanocomposite thin films were fabricated by the simple sonochemical deposition of Ag on preformed aerosol-assisted chemical vapor deposited TiO2 thin films. The photelectrocatalytic performance of a newly fabricated Ag/TiO2-modified photoelectrode was studied for methanol oxidation under simulated solar AM 1.5G irradiation (100 mW/cm2). The Ag/TiO2-modified photoelectrode showed a photocurrent density of 1 mA/cm2, which is four times that of an unmodified TiO2 photoelectrode. The modification of Ag on the TiO2 surface significantly enhanced the photoelectrocatalytic performance by improving the interfacial charge transfer processes, which minimized the charge recombination. Density functional theory (DFT) calculation studies revealed that methanol could be easily adsorbed onto the Ag surfaces of Ag/TiO2 via a partial electron transfer from Ag to methanol. The newly fabricated Ag/TiO2-modified photoelectrode could be a promising candidate for photoelectrochemical applications

Reduced graphene oxide-titania nanocomposite-modified photoanode for efficient dye-sensitized solar cells

We report the successful application of reduced graphene oxide–titania (rGO–TiO2) nanocomposite as an efficient photoanode for dye‐sensitized solar cell (DSSC). The DSSC assembled with the rGO–TiO2‐modified photoanode demonstrated an enhanced solar to electrical energy conversion efficiency of 4.74% compared with the photoanode of DSSC composed with unmodified TiO2 (2.19%) under full sunlight illumination (100 mW/cm2, AM 1.5G) as a result of the better charge collection efficiency of rGO, which reduced the back electron transfer process. Influence of the rGO content on the overall efficiency was also investigated, and the optimal rGO content for TiO2 was 0.5 mg. Further, the modification of rGO–TiO2 on the compact layer TiO2 surface led to an increase in efficiency to 5.83%. The superior charge collection and enhanced solar energy conversion efficiency of the rGO–TiO2 nanocomposite makes it to be used as a promising alternative to conventional photoanode‐based DSSCs

Essential role of N and Au on TiO2 as photoanode for efficient dye-sensitized solar cells

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

In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells

This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30 nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I3−/I− redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs

Boosting photovoltaic performance of dye-sensitized solar cells using silver nanoparticle-decorated N,S-co-doped-TiO2 photoanode

A silver nanoparticle-decorated N,S-co-doped TiO2 nanocomposite was successfully prepared and used as an efficient photoanode in high-performance dye-sensitized solar cells (DSSCs) with N719 dye. The DSSCs assembled with the N,S-TiO2@Ag-modified photoanode demonstrated an enhanced solar-to-electrical energy conversion efficiency of 8.22%, which was better than that of a DSSC photoanode composed of unmodified TiO2 (2.57%) under full sunlight illumination (100mWcm−2 , AM 1.5 G). This enhanced efficiency was mainly attributed to the reduced band gap energy, improved interfacial charge transfer, and retarded charge recombination process. The influence of the Ag content on the overall efficiency was also investigated, and the optimum Ag content with N,S-TiO2 was found to be 20wt%. Because of the enhanced solar energy conversion efficiency of the N,STiO2@Ag nanocomposite, it should be considered as a potential photoanode for high-performance DSSCs

Validation of the Malay version of the p-QOL questionnaire

Introduction This study aimed to translate and validate the P-QOL questionnaire in the Malay language. Methods The P-QOL questionnaire was translated into the Malay language and subsequently back-translated to English. Testretest reliability and internal consistency were tested. All patients who visited the gynecology outpatient clinic of UKMMC, UMMC and IIUM between January 2016 and May 2017 completed the P-QOL questionnaires and were assessed for POP-Q staging. Results One hundred twenty patients with symptomatic pelvic organ prolapse and 180 asymptomatic patients were included. The Cronbach’s alpha for each domain was > 0.70, which confirmed that there was a highly acceptable internal consistency. The value varied between 0.88 (role limitation) and 0.912 (sleep/energy). Test-retest reliability showed a significant correlation between the total scores for each domain (p < 0.001). There was a significant correlation between P-QOL domain scores and vaginal examination findings (POP-Q). With a higher POP-Q stage, a higher impact on the quality of life was detected in symptomatic patients. The total scores from all domains were significantly higher in symptomatic patients. Conclusion The Malay translated version of the P-QOL questionnaire is a reliable, consistent, and valid instrument for assessing the severity of the symptoms and impact on the quality of life among women with uterovaginal prolapse. It is easily understood, administered, and self-completed by patient

Microstructural changes of carbonaceous monoliths synthesized via hydrothermal method

Carbonaceous monoliths were successfully synthesized via a facile hydrothermal processing route using phenol as a carbon precursor. The x-ray diffraction (XRD) patterns revealed distinguishable (002) and (100) planes of graphite at approximately 2θ = 23° and 44°, respectively. The fourier transform infrared (FTIR) spectroscopy corresponded to the chemical bonds of graphite, which were C=C and C-H. The carbonaceous monoliths exhibited interesting morphological changes as a result of varying the type of polymer which acted as a structure directing agent, mass of polymer, mass of phenol and hydrothermal temperature before and after calcination

Titania@gold plasmonic nanoarchitectures: an ideal photoanode for dye-sensitized solar cells

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