Optimized Nanostructured Titania for Organic-Inorganic Solid State Solar Cells

BORIS BOAGLIO; IANINA VIOLI; M. DOLORES PEREZ

Boulder

Otro; I-CAMP Summer School on Renewable and Sustainable Energy; 2012

The field of hybrid photovoltaic devices has become increasingly attractive due to the potential advantages of using organic and inorganic semiconductors combined. However, many challenges remain, especially in the development of optimized inorganic materials for optoelectronic applications. In this work, we carefully design an inorganic titania nanoframework with highly accessible mesochannels, ordered pores and crystalline walls onto a transparent conductive oxide (ITO, Indium Tin Oxide). We introduce a thin dense titania layer to modify the ITO surface, followed by the sol-gel deposition of the mesoporous titania that is further exposed to thermal treatment. The inorganic structure is studied by several techniques like electronic microscopy, X-ray diffraction and environmental ellipsometric porosimetry (EEP). An organic material is later impregnated into the nanostructure from a toluene solution. The organic infiltration into the porous titania is studied by UV-vis absorption spectrum, SEM and EEP to determine pore blockage. Solar devices are completed by evaporation of a metallic contact and I-V characteristics and spectral response are determined. This work constitutes an early approach to the understanding of novel materials for new solar technologies. The focus here is based on the optimization of the inorganic semiconductor but we intend to apply a number of other organic materials in order to enhance solar responsivity and efficiencies.