Investigation of charge transport, photo generated electron transfer and photovoltaic response of iron phthalocyanine (FePc):TiO2 thin films

We have investigated the blend of semiconducting materials (iron(II) phthalocyanine (FePc)) with TiO2 nano crystals (NC) for photovoltaic application. The photo-induced electron transfer in composite of TiO2 with FePc is studied by means of photoluminescence (PL) of the blend as well as photo-action spectra of the device. The quenching of the PL and occurrence of broad absorption have been interpreted as an electron transfer between an organic semiconductor and TiO2 (NC) in excited state. Also, the effects of hole mobility and light intensity on the device properties have been analyzed. The observation of an increase in photocurrent of the device (consisting of TiO2) is interpreted by the formation of an interconnecting network of FePc with TiO2 nano particle and formation of bulk hetero junction between aluminum (Al) and indium tin oxide (ITO) electrodes. The electron transfer between FePc and TiO2 is induced by photo excitation. The experimental results were explained with the help of a model that describes total current density as a function of injected carriers as donor/acceptor interface and contributed photo-generated current is due to the efficient dissociation of excitons.