Fabrication and Characterization of Hybrid Nano-Polymer Solar Cells
Hybrid solar cells consist of organic as well as inorganic substances. An organic compound absorbs light and transports holes whereas an inorganic compound is an acceptor and transports electrons. Hybrid solar cells were fabricated on glass slides pre-coated with indium tin oxide (ITO) which itself acts as a cathode. Poly(3,4 ethylenedioxythiophene)polystyrenesulfonate (PEDOT:PSS) was coated in order to avoid a short circuit between the layers and also to smooth the surface of ITO. A photoactive layer which consisted of poly(3-hexathiophene) (P3HT), TiO2 and star dispersant was coated over the PEDOT:PSS layer. Gold/molybdenum was sputtered as an anode material. Star dispersant was added to the active layer in order to improve the performance of the solar cell. Introduction of star dispersant increases the interfacial area and in turn the exciton dissociation. Atomic force microscopy (AFM) was used to measure the thicknesses of the individual layers and also to obtain a topographical view of the cell surface to ensure the uniformity of the deposited layers. Absorption and photoluminescence spectra were measured to characterize the solar cell. Finally, current–voltage characteristics were measured to ensure that the solar cell acts as a diode.