Patents

A  polymer based solar cell of conventional geometry includes donor and acceptor material sandwiched between transparent conducting  indium tin oxide (ITO) and a low work function metal electrode (sometimes a combinational Ca/Al of same size), by which holes and electrons are collected, respectively. The disadvantage of using combinational Ca/Al of same size is that the edges being attacked by the environment viz., moisture and oxygen that results in to faster degradation of the device and less life time. Disadvantage has been overcome by present invention where extended Ca (beyond Al film size) layer prevents the degradation owing to its oxidation by the attack by moisture and oxygen and thus improving the life time from ~70 hrs to 400 hrs. Moreover, the encapsulated device shows further improvement in life time up to more than 1000 hrs.