High Efficiency Dye-sensitized Solar Cells Constructed with Composites of TiO2 and the Hot-bubbling Synthesized Ultra-Small SnO2 Nanocrystals

Photo-Assisted Rechargeable Battery Desalination

Herein, we propose a novel design of photo-assisted battery desalination, which provides the tri-function within a single device including the photo-assisted charge (electrical energy saving), energy storage, and desalination (salt removal). The photoelectrode (N719/TiO₂) is directly integrated into the zinc-iodide (Zn-I) battery with the desalination stream in the middle portion of the device. This architecture can provide a reduced energy consumption up to 50%, an energy output of 42 W h mol^-1_NaCl, and a desalination rate of 13 μg/cm² min^-1. This work is significant for the inter-discipline study of the redox flow energy storage and energy-saving desalination.

Semiconductors as Effective Electrodes for Dye Sensitized Solar Cell Applications

As proficient photovoltaic devices, dye-sensitized solar cells (DSSCs) have received considerable consideration in recent years. In order to accomplish advanced solar-to-electricity efficiency and increase long-term functioning stability, improvements in the configuration structure of DSSCs are essential, as is an understanding of their elementary principles. This work discusses the application of different semiconductor constituents designed for effective DSSCs. The main parameters crucial to fabrication of DSSC electrodes in nano-porous semiconductor structures are high surface area and large pore size. Different inorganic semiconductor materials are used to load sensitizer dyes, which absorb a lot of light and induce high photocurrent for efficient DSSCs. The first section of the review covers energy sources, photovoltaics, and the benefits of solar cells in daily life, while the second part includes the various types of semiconductors applied in DSSC applications. The final section provides a brief review of future perspectives for DSSCs and a survey of semiconductor materials proposed for solar cell applications.

Solvent assisted evolution and growth mechanism of zero to three dimensional ZnO nanostructures for dye sensitized solar cell applications

We report the structural engineering of ZnO nanostructures by a consistent solution method using distinct solvents such as ethylene glycol, 1-butanol, acetic acid and water. The growth kinetics are found to depend strongly on the physicochemical properties of the solvent and zeta potential of the colloidal solution. Furthermore, the resulting nanostructures as a photoanode material, displayed a prominent structure dependent property in determining the efficiency of dye-sensitized solar cells (DSSCs). The fabricated solar cell with ZnO nanostructures based photoanode exhibited improved conversion efficiency. Moreover, the nanoflower based DSSCs showed a higher conversion efficiency of 4.1% compared to the other structures. The excellent performance of ZnO nanoflower is attributed to its better light-harvesting ability and increased resistance to charge-recombination. Therefore ZnO nanostructures can be a promising alternative for TiO2 in DSSCs. These findings provide new insight into the simple, low cost and consistent synthetic strategies for ZnO nanostructures and its outstanding performance as a photoanode material in DSSCs.

Revealing the Correlation of the Electrochemical Properties and the Hydration of Inkjet-Printed CdSe/CdS Semiconductor Gels

The mobility of charge carriers across a semiconductor-nanoparticle-based 3D network (i.e., a gel) and the interfacial transfer of the charge carriers across the nanoparticle network/electrolyte boundary are elementary processes for applications in the fields of sensing and energy harvesting. The automated manufacturing of electrodes coated with porous networks can be realized by inkjet printing. By simultaneous printing of CdSe/CdS dot-in-rod-shaped nanorods (NRs) and the destabilization reagent, CdSe/CdS gel-network-coated electrodes can be obtained. In this work, the charge carrier mobility of the electrons and the holes within the porous CdSe/CdS nanorod gel network is investigated via photoelectrochemistry. Using linear sweep voltammograms (LSVs) and intensity-modulated photocurrent spectroscopy (IMPS), it is shown that the electron is moving within the tip-to-tip-connected CdSe/CdS NR gel structure, while the holes are trapped in the CdSe seed of the semiconductor heterostructures. Furthermore, the preparation process of gel structures is related to the elementary mechanism of hydration, which can be shown via photoelectrochemical long-term studies.

Patterning of Nanoparticle-Based Aerogels and Xerogels by Inkjet Printing

Nanoparticle-based voluminous 3D networks with low densities are a unique class of materials and are commonly known as aerogels. Due to the high surface-to-volume ratio, aerogels and xerogels might be suitable materials for applications in different fields, e.g. photocatalysis, catalysis, or sensing. One major difficulty in the handling of nanoparticle-based aerogels and xerogels is the defined patterning of these structures on different substrates and surfaces. The automated manufacturing of nanoparticle-based aerogel- or xerogel-coated electrodes can easily be realized via inkjet printing. The main focus of this work is the implementation of the standard nanoparticle-based gelation process in a commercial inkjet printing system. By simultaneously printing semiconductor nanoparticles and a destabilization agent, a 3D network on a conducting and transparent surface is obtained. First spectro-electrochemical measurements are recorded to investigate the charge-carrier mobility within these 3D semiconductor-based xerogel networks.

Hierarchical TiO2 microspheres composed with nanoparticle-decorated nanorods for the enhanced photovoltaic performance in dye-sensitized solar cells

Hierarchical TiO₂ microspheres composed of nanoparticle-decorated nanorods (NP-MS) were successfully prepared with a two-step solvothermal method. There were three benefits associated with the use of NP-MS as a photoanode material. The decoration of nanoparticles improved the specific surface area and directly enhanced the dye loading ability. Rutile nanorods serving as electron transport paths resulted in fast electron transport and inhibited the charge recombination process. The three-dimensional hierarchical NP-MS structure supplied a strong light scattering capability and good connectivity. Thus, the hierarchical NP-MS combined the beneficial properties of improved scattering capability, dye loading ability, electron transport and inhibited charge recombination. Attributed to these advantages, a photoelectric conversion efficiency of up to 7.32% was obtained with the NP-MS film-based photoanode, resulting in a 43.5% enhancement compared to the efficiency of the P25 film-based photoanode (5.10%) at a similar thickness. Compared to traditional photoanodes with scattering layers or scattering centers, the fabrication process for single layered photoanodes with enhanced scattering capability was very simple. We believe the strategy would be beneficial for the easy fabrication of efficient dye-sensitized solar cells.

Hierarchical NP-MS combines the beneficial properties of improved scattering capability, dye loading ability, electron transport and inhibited charge recombination. The photoelectric conversion efficiency up to 7.32% has been obtained.

Dye-Sensitized Solar Cells: Fundamentals and Current Status

Dye-sensitized solar cells (DSSCs) belong to the group of thin-film solar cells which have been under extensive research for more than two decades due to their low cost, simple preparation methodology, low toxicity and ease of production. Still, there is lot of scope for the replacement of current DSSC materials due to their high cost, less abundance, and long-term stability. The efficiency of existing DSSCs reaches up to 12%, using Ru(II) dyes by optimizing material and structural properties which is still less than the efficiency offered by first- and second-generation solar cells, i.e., other thin-film solar cells and Si-based solar cells which offer ~ 20-30% efficiency. This article provides an in-depth review on DSSC construction, operating principle, key problems (low efficiency, low scalability, and low stability), prospective efficient materials, and finally a brief insight to commercialization.

Broadening the sunlight response region with carbon dot sensitized TiO2 as a support for a Pt catalyst in the methanol oxidation reaction

Carbon dots with upconversion properties harness unused visible light and act as sensitizers for a TiO₂ supported Pt catalyst in MOR.

Synthesis of chitosan capped copper oxide nanoleaves using high intensity (30kHz) ultrasound sonication and their application in antifouling coatings

The synthesis of chitosan capped copper oxide nanoleaves (CCCO NLs) was carried out under three different reaction conditions viz. 1) room temperature, 2) 70°C and 3) high intensity ultrasound (30kHz) sonication method and it has been found that the high intensity ultrasound (30kHz) sonication is the best method when compared to other two methods. The advantages of the present synthetic method are: i) easy one step process, ii) lesser reaction time, iii) good yield, iv) reproducible and v) calcination is not required. The resulting chitosan capped copper oxide nanoleaves were characterized by Diffuse Reflectance UV-Visible Spectroscopy (DRS), Fourier Transform Infra-Red Spectroscopy (FT-IR), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM) and Thermo gravimetric analysis (TGA). The CCCO NLs were blended with commercial paints such as polyurethane clear, polyurethane white and acrylic emulsion and applied on to three different surfaces (wood, mild steel and cement slab panels). The hydrophilicity of CCCONP coated panels was analyzed by water contact angle measurement and their antifouling behavior was investigated against three different green and marine algae viz. Arthrospira, Chlorella and Amphora. The antifouling efficiency of the CCCO NLs against the algae was found to be 78-92%.