Carbazole Functionalized Isocyanide Brushes in Heterojunction Photovoltaic Devices

Eunhee Lim, Feng Gao, Erik Schwartz, Jeroen J L M Cornelissen, Roeland J M Nolte, Alan E Rowan, Neil C Greenham, Lee-Mi Do

In this work, carbazole-containing polyisocyanide (PIACz) brushes were used for photovoltaic devices. A photovoltaic device was fabricated on top of the brushes by spin-coating a suitable acceptor and evaporating an Al cathode. Devices with a poly(N-vinylcarbazole) (PVK) bulk polymer were also prepared for comparison. Interestingly, the brushes showed better photovoltaic characteristics as compared to the blended PVK system. This is attributed to the specific morphologies of the polyisocyanide brushes, which provide a large interfacial area between the donor and acceptor for efficient photogeneration. It was found that the device performance varied according to the molecular size of the incorporated acceptors.