Plastic Solar Cells “the nex-gen power”
AbhishekModi 4TH Sem ECE
Technology has reached to such a dizzy height that man leaves no stone unturned to find the least alternatives. Such an innovation has led to the rise of plastic solar cells; rightly called “the next-gen power”. These cells apart from their specific design & cost converts solar energy into electric energy in a very cost-effective way. In addition with being cost-effective, plastic solar panels are also flexible, light weight, and thin, which enables new applications, not possible using traditional silicon solar panel technology; thus providing renewable energy from sun. They open up a wide range of new application areas in renewable energy, which are not currently addressable with conventional silicon solar panel technology. Plastic solar panels will be the first in solar capable of generating electricity on par with conventional fuel costs.
Plastic solar cell technology has the advantage over other renewable sources of energy in a numerous ways.Low cost of raw material and manufacturing ,low material usage, fabrication at low temperature and ecofriendly are some of the factors that supports the use of plastic solar cells. The development of inexpensive, mass-produced plastic solar panels is a goal of intense interest for many of the world's scientists and engineers because of the high cost and shortage of the ultra-high purity silicon and other materials normally required.
Organic plastic is intrinsically flexible and easy to bond to flexible substrates such as plastic and metal foils. Combined with the extremely thin active layer, this enables light weight and flexible applications. Starting from mobile charging to driving a battery powered vehicle these cells find utmost importance in our day-to-day life.
Plastic solar cells are made up of layers of different materials, each with a specific function, called a sandwich structure. One layer absorbs the light, another helps to generate the electricity, and others help to draw the electricity out of the device. Normally, the layers don't stick well, and so the electricity ends up stuck and never gets out, leading to inefficient devices. A new process for printing plastic solar cells boosts the power generated by the flexible and cheap form of photovoltaics. The bottom cell is filled with a proprietary polymer. The polymer (a derivative of polythiophene) absorbs both infrared and ultraviolet light. Next comes a titanium-suboxide layer, which seals in the bottom cell, provides a foundation for building the top layer, and, as it's a metal, efficiently carries away the charged electrons generated in both layers. Finally, the top layer sports a different type of conducting polymer that absorbs mostly blue and green light. . Efficiency is significantly lower, however, because polymers are poor charge conductors.
These organic semiconductors are soft, carbon-based materials synthesized from products (often byproducts) of the petroleum industry. The molecular structures of these materials have an alternating arrangement of single and double bonds between carbon atoms. A system of atoms arranged in this way is said to be conjugated which is the basis of everyday effects such as the colors of chlorophyll and beta-carotene. Such a molecule accommodates electric charge relatively easily, by allowing the charge to spread out over all its atoms. Conjugated molecules together form a solid semiconductor, with properties like those of silicon. The absorption of light and the separation of charges take place within a thin film of about one hundred nanometers. This film contains both n- and p-type materials, and is sandwiched between two types of electrodes: a transparent electrode and a reflective electrode. The transparent electrode usually collects holes, while the reflective electrode usually collects electrons. If efficient plastic solar cells could be made inexpensively, what would be the outcome? The dream is that energy would be revolutionized through the use of cheap solar material that could be paved onto flat expanses or spray-painted onto cars. Realistic and short-term applications for plastic solar cells include lightweight power sources for portable (even wearable) electronics; low-cost, off-grid power for rural areas of developing countries; and other applications in which low cost, rather than state-of-the-art efficiency, is the goal. Plastic solar cells could become an important source of renewable energy, but more research is required to overcome limitations in efficiency. Nevertheless a better future of clean energy can be expected in the near future.