FABRICATION OF ORGANIC SOLAR CELLS USING EMBEDDED MATRIX OBTAINED VIA INSITU GROWTH OF CDS NANOPARTICLES IN P3HT

Abstract

The present 'Global Warming' up phenomenon has changed the world energy scenario to focus on the importance of Renewable Energy sources for augmenting power production worldwide. Of these, Solar and wind power are the most important sources. The Solar photovoltaic (PV) industry experienced a healthy growth rate of over 40% in the last 5 years. The cumulative total of PV systems installed in India is 250 MW in the year 2006 including export of 160 MW. India position was 4th in the world in 2004 in solar production. India had started country wide Solar Photovoltaic Program for about two decades and has installed an aggregate 1.3 million systems. The expansion trend of the photovoltaic (PV) industry as one of the most promising renewable energy sources is observed majorly in Japan, United States and Europe. More than 85% of the current world productions of PV cells involve crystalline silicon. Nevertheless, after several years of intensive research and development, a new generation of devices is in transition from small to large-scale production. This one is based on inorganic materials like CdTe and CuInSe (CIS), etc. But beyond thissecond generation, a third one is intensively considered. These latter calls upon an entirely new type of materials, namely, the organic semiconductors. Interest in organic solar cells stems primarily from the promise of ease of processing. This is because, to date, many organic solar cell devices have used polymers as integral parts of their construction. For example, conjugated polymers often participate as electron donors and hole conductors in the active layer of the organic solar cells. Since the science of polymer processing is well developed, it is hoped that one day conventional processing steps such as roll-to-roll processing can be employed to make large-area inexpensive organic solar cells on flexible substrates which can be used in countless ways, from handheld electronics to commercial power production. However the research on organic solar cell still have a long way to go to compete with inorganic solar cells. The efficiency of inorganic solar devices is upto 20% and the development of inorganic thin layer and multi junction devices will likely lead to even better performance. In contrast, the optimum efficiency of organic solar cell based on the bulk hetrojunction concept is 4-5%. Another problem with these devices is the stability, as they degrade much faster than the inorganic one and hence performance of the devices decreases with the time. As per our M.Tech curriculum, during the final semester which is totally research oriented we have worked on above problems and to meet some improvement in those areas and hence to achieve the better performance of the organic solar cell, we have learnt the working and fabrication process and then worked on efficiency and stability.