Inverted polymer solar cells integrated with a low temperature annealed sol gel derived ZnO Film as an electron transport layer.
BHJ solar cells are typically fabricated with a transparent conductive anode (e.g. indium tin oxide, ITO) a low work function metal cathode (e.g. Al, Ca) and an active layer (a mixture of conjugated polymer and fullerene derivative) sandwiched between the anode and cathode. The BHJ layer and cathode dramatically affect the stability. In particular, the cathode is susceptible to degradation by oxygen and water vapor. Poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is often used as an anode buffer layer. Long term stability is a problem because PEDOT:PSS is hygroscopic and acidic. 17 21
Advanced materials