Production of original solar cells based on fragile silicon wafers, is difficult, expensive and energy intensive. Thin film solar cells were introduced as a more durable, less expensive option, but their energy efficiency is lesser. The latest solar technologies in which many types of materials are being researched (viz organic alternatives and titanium dioxide) offer higher-efficiencies and are more economical. Compared to silicon-based devices, polymer solar cells are lightweight (which is important for small autonomous sensors), potentially disposable and inexpensive to fabricate, flexible, customizable on the molecular level, and have lower potential for negative environmental impact. They can be bonded to almost any surface which makes them ideal for charging cell phones, laptops, or MP3 players. Plastic solar cells will find increasing application in portable devices, as ability to deliver longer battery life will be an important issue to the device manufacturers. But so far, these devices have been too inefficient to compete with silicon solar cells for most applications. Solar market presently valued at US$20 billion and is predicted to grow by around 30% pa for the next decade. Konarka Technologies is one company moving into mass production of plastic solar cells. One of the first products targeted to use Konarka's cells will be briefcases coated on the outside with a film of the organic solar cells that charge the laptop within. This is hoped to be achieved with organic thin-film plastic that it claims can convert sunlight into electricity more efficiently than its competitors, with a lower manufacturing cost. Plastic solar cells are now being incorporated into fabrics such as clothing and tents. Applications may include military uniforms to provide power for lighting, heating, and remote command technologies as per www.worldofphotovoltaics.com. Solar panels can be mounted on to carrier bags and clothing to enable wearers to use the energy to charge tents, consumer electronics goods, mobile phones, etc. North Carolina State University designed a process to fit plastic solar panels to ties and jackets. A solar blouse that will charge a cell phone has been developed in Japan. An American has designed a solar powered bikini, which can supply 6.5 volts to charge up an iPod or keep a drink cold. Off-grid villagers in Africa, Asia, and Latin America still rely on kerosene lamps and candles. Frederik Krebs has developed lamps providing an affordable alternative to kerosene lighting for the more than 1.5 billion people in developing countries who lack access to electricity. He prints their polymer solar cells and circuitry onto rolls of 25-micrometer-thick flexible plastic film by the hundreds of square meters, using standard screen and slot-die presses. Next, a circuit of copper tape is printed onto the solar cells, and the components-surface-mounted LEDs, flat batteries, and a diode-are mounted using silver epoxy. The whole thing is then encapsulated in a second sheet of film. The lamps are expected to operate for at least a year, and will cost less than 25% of the buyers' present annual lighting budget. Now research studies are resulting in polymer solar cells with good efficiencies, increasing at a rate of about 1% pa- a rate fast enough for plastic solar cells to be competing with silicon within a few years. Solarmer Energy, Inc. is developing plastic solar cells for portable electronics by incorporating technology invented at the University of Chicago. The product is a cell that measures t 8 sq inches and is expected to be 8% energy efficient. The new technology uses a new semi conducting material called PTB1, which converts sunlight into electricity. The active layer of PTB1 is a 100 nanometers thick. Professor Guillermo Bazan and a team of postgraduate researchers at UC Santa Barbara's Center for Polymers and Organic Solids (CPOS) have announced a major advance in the synthesis of organic polymers for plastic solar cells team that reduced reaction time by 99%, from 48 hours to 30 minutes, and increased average molecular weight of the polymers by a factor of more than 3. The reduced reaction time effectively cuts production time for the organic polymers by nearly 50%, while the higher molecular weight of the polymers, reflecting the creation of longer chains of the polymers, has a major benefit in increasing current density in plastic solar cells by as much as a factor of more than four. The team plans to take advantage of this approach to generate new materials that will increase solar cell efficiencies and operational lifetimes, and to reevaluate previously-considered polymer structures that should exhibit much higher performance. An international group of scientists has developed a polymer-based solar cell with an ability not yet seen in similar cells: almost every single photon it absorbs is converted into a pair of electric-charge carriers, and every one of those pairs is collected at the cell's electrodes. The overall efficiency of the cell is 6%, resulting in a total of 6% of the absorbed energy being converted into usable electricity when illuminated in the lab with simulated solar light. The work is a good sign that it is possible to produce polymer solar cells with efficiencies good enough for commercial production. The solar cell is made of a “copolymer,” a polymer consisting of two different alternating polymer chains. Its role is to release electrons when hit by sunlight; the electrons are accepted by a fullerene derivative, a material based on a form of carbon that tends to form large spherical molecules known as fullerenes. When the two materials are combined into a composite “active layer,” regions form that separating the positive and negative charge - the positively charged “holes” left by electrons as they leave the copolymer and, of course, the electrons themselves. A study by researchers at the UCLA Henry Samueli School of Engineering and Applied Science found that substituting a silicon atom for carbon atom in the backbone of the polymer markedly improved the material's photovoltaic properties. This silole-containing polymer can also be crystalline, giving it great potential as an ingredient for high-efficiency solar cells. The new polymer reached 5.6% efficiency in the lab. The team have proven that the photovoltaic material used on their solar cells is one of the most efficient based on a single-layer, low-band-gap polymer when a polymer can better utilize the solar spectrum, thereby absorbing more sunlight. The team has been able to simplify the process and make it much easier to mass produce. Danish researchers have connected a polymer solar cell plant to an electrical grid in a successful world-first demonstration of how the promising renewable energy technology can be integrated into power systems. After the production of the solar cells - and in collaboration with Gaia Solar A/S - Risø DTU has manufactured large panels upon which the solar cells are mounted. Gaia Solar A / S specialize in module construction of silicon solar cell panels and have built Risø's polymer solar cells into their design. The panel is placed on a tracker which follows the movement of the sun. The generated power is added to the grid. The Eindhoven University of Technology and the University of Ulm have made the first high-resolution 3D images of the inside of a polymer solar cell. They created hybrid solar cells using a mixture of two different materials - a polymer and a metal oxide, which were used to create charges at their interface when the mixture was illuminated by the sun. They hope to increase their power conversion efficiency of 2% by creating polymers that can interact with the metal oxide and by developing polymers or molecules that absorb a larger part of the solar spectrum. At such point, the intrinsic advantages of hybrid polymer solar cells in terms of low cost and thermal stability of the nanoscale structure could be fully exploited. With the solar market currently worth US$20 billion and predicted to grow by around 30% a year for the next decade clearly there will be an increase in research and development and more companies will enter the market to keep up with demand.