Global environmental concerns and the escalating demand for energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Solar energy is the most abundant, inexhaustible and clean of all the renewable energy resources till date. The power from sun intercepted by the earth is about 1.8 × 1011 MW, which is many times larger than the present rate of all the energy consumption. Photovoltaic technology is one of the finest ways to harness the solar power. This paper reviews the photovoltaic technology, its power generating capability, the different existing light absorbing materials used, its environmental aspect coupled with a variety of its applications. The different existing performance and reliability evaluation models, sizing and control, grid connection and distribution have also been discussed. © 2011 Published by Elsevier Ltd.

A review of solar photovoltaic technologies

Lasers provide the ability to accurately deliver large amounts of energy into confined regions of a material in order to achieve a desired response. For opaque materials, this energy is absorbed near the surface, modifying surface chemistry, crystal structure, and/or multiscale morphology without altering the bulk. This chapter covers a brief introduction to the fundamental principles governing laser propagation and absorption as well as the resulting material responses. We then highlight two case studies of improving efficiency in photovoltaic and optoelectronic devices as well as optimizing cell-surface interactions in biological interfaces.

Fundamentals of Laser-Material Interaction and Application to Multiscale Surface Modification

Design, fabrication, and characterization of a broadband, omnidirectional, graded-index antireflection (AR) coating made using nanostructured low-refractive-index (n=1.05–1.40) silica deposited by oblique-angle deposition are reported. Averaged over wavelength range from 400 to 1100 nm and 0°–90° angle of incidence, polished Si reflects ∼37% of incident radiation. The reflection losses are reduced to only 5.9% by applying a three-layer graded-index AR coating to Si. Our experimental results are in excellent agreement with theoretical calculations. The AR coatings reported here can be optimized for photovoltaic cells made of any type of material.

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Nanostructured multilayer graded-index antireflection coating for Si solar cells with broadband and omnidirectional characteristics

Dye Sensitized Solar Cell (DSSC) is considered to be one of the most promising technological developments in the field of Solar Cells. It is basically a cell that imitates the process seen in plant cells to produce energy. It is a photo-electrochemical cell, considering the electron moments caused by the combined effect of the photon energy and the chemical reactions. The DSSC being transparent to some extent and comparatively cheaper than conventional solar photo-voltaic, can be a potential energy source for the future. But there are many aspects that need to be worked upon before declaring it as a feasible commercial product. The paper emphasizes on these aspects and the various improvements that the DSSC has gone through in recent years. This is a detailed review of the work done to improve the performance of DSSC, with supporting data. A comparative study of the effect of various suggested modification to the different components of DSSC has been done. This would give a clear idea about the most recent improvements done in DSSC with respect to the various components. It includes a summary of the suggested improvements by various researchers, bifurcated into different sections with respect to the different components of the DSSC. It was observed that incorporating graphene sheets of various sizes in the photo anode helped to improve the efficiency of DSSC significantly, giving a maximum efficiency of 6.62%. In case of novel dyes used in the DSSC fabrication the D-A-pi-A indoline dyes showed a great enhancement in the cell efficiency, with efficiency of up to 6.9%. Incorporation of Pt in counter electrodes and 3D-CE also showed notably good efficiency in DSSC, the efficiency improving up to 8.8%.

Recent improvements in dye sensitized solar cells: A review

Graphene oxide (GO) is useful and promising material for graphene based applications in electronic, optics, chemistry, energy storage and biology. At the beginning of graphene history GO was only a simple and cheap step for preparation of single and multilayer graphene films and bulk structures by reduction. The further studies revealed the substantial structure imperfection of graphene oxide derived materials due to the defects in initial graphite and incompletion of reducing process. However, the results of recent research demonstrated a great amount of unique chemical, optical and electronic properties of graphene oxide that allow regarding it as independent nanomaterial possessing a large area of applications. In general, it represents the ultra-large organic molecule containing 2D carbon mesh. Unlike conventional graphene it provides wide range of chemical methods for attachment of various functional groups to its surface for control optical transparency, electrical and thermal conductance. Recently developed methods for preparation of graphene oxide derivatives saturated by carboxyl groups open the new attractive application areas in green technologies including energy storage and utilizing nuclear wastes. The goal of the review is to summarize the results of recent studies of graphene oxide, derivatives and reveal the most promising directions to focus the efforts of researchers.

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Graphene Oxide and Derivatives: The Place in Graphene Family

Facile Route to Prepare Hybrid Tio2-Sno2 Dsscs

Purpose: The aim of the paper is to determinate basic parameters for components of demonstrative system which is traffic light pedestrian crossing. Design/methodology/approach: Photovoltaic module was produced from monocrystalline silicon solar cells which were joined in series. Photovoltaic system consists of solar module, astable generator, step-down converter and battery pack. Findings: Its necessary to protect photovoltaic system from external factor like unstable light conditions, variable input voltage, shading. Taking this fact into account photovoltaic system with step- down converter was designed. Step-down converter adjust the voltage of photovoltaic module to the voltage of battery protecting them from overcharging and discharging. Research limitations/implications: The main goal of this work is to show the practical use of widely available, renewable energy source, which is the Sun through the selection of component for the demonstrative photovoltaic system -traffic light pedestrian crossing. Practical implications: In order to provide access to electricity in areas with limited access to power network, there irreplaceable are stand-alone photovoltaic systems, which can supply both AC and DC devices. Originality/value: The produced photovoltaic system confirms the usefulness of solar energy in every place where sunlight is available. In order to provide steady supply at night and in low sunlight the battery stores energy was applied.

Selection of components for photovoltaic system

Purpose: The aim of the paper is to fabricate the dye-sensitized solar cells DSSC with

Technology of dye-sensitized solar cells with carbon nanotubes

Nadążny system fotowoltaiczny sterowany komputerowo

Purpose: The presented in this paper research results concern investigation of phase transformation of the surface structure of polycrystalline silicon solar cell. The surface of boron doped polycrystalline silicon wafers were texturised by means of diode-pumped pulsed neodymium-doped yttrium aluminium garnet laser crystal (Nd:YAG). Investigations were carried out on transmission electron microscope (TEM) to observe the changes that occurred after laser treatment of the surface layer. Changes in microstructure of the surface layer of solar cells under the influence of the laser beam are presented using the analysis phase and dislocations present in the microstructure. Observations were carried out on prepared thin foils. Moreover, diffraction patterns from selected regions of textured wafers were solved to qualify phase transformations under influence of laser beam. Design/methodology/approach: Investigations were carried out on the Transmission Electron Microscope JEM 3010 supplied by JEOL with 300 kV accelerating voltage equipped with an electronic camera configured with a computer. The microstructure was obtained in the bright field image as well dark field working in a magnification range of 10000x to ca. 100000x. Phases identification was performed by means of selected area diffraction (SAD) method, where for diffraction pattern calculations the computer software “Eldyf” was used, kindly supplied by the Institute of Materials Science, University of Silesia. Findings: The research included analyze of the influence of laser treatment conditions on geometry, roughness and size of laser made surface texture of silicon wafer applied for solar cells. Research limitations/implications: Paper contributes to research on silicon surface processing using laser beam. Practical implications: Conducted investigations may be applied in optimisation process of solar cell surface processing. Originality/value: The range of possible applications increases for example as materials for solar cells placed on building constructions, elements in electronics and construction parts in automobile industry.

Aleksandra Drygała

Papers

Facile Route to Prepare Hybrid Tio2-Sno2 Dsscs

Selection of components for photovoltaic system

Technology of dye-sensitized solar cells with carbon nanotubes

Nadążny system fotowoltaiczny sterowany komputerowo

TEM investigations of laser texturized polycrystalline silicon solar cell