ICT2014 Abstracts

Renewable sources of power generation are presented as one of the alternatives to achieve global carbon emission targets. Among renewable power generation, solar power is still considered in its infancy because photovoltaic (PV) cells have not achieved efficiencies and cost that can that put solar cell in a competitive advantage. Dye sensitized solar cell (DSSC) is an alternative technology to traditional photovoltaic solar cells because it is prepared from relative inexpensive materials, and it shows an acceptable efficiency. Due to the photosensitive nature of the organic dye, DSSC generally operates within the ultraviolet to visible region. These regions represent only a fraction of the entire solar spectrum. Collecting more of the infrared (IR) radiation would increase the overall efficiency of the system making DSSC more competitive. Integrating a thermoelectric element to a DSSC could increase the overall efficiency. Achieving a larger efficiency due to the collection of the UV to IR spectrum is the motivation of our proposed ultra-wide solar spectrum photovoltaic-thermoelectric (PV-TE) solar power cell. The understanding of the thermoelectric and charge transfer characteristics for the proposed PV-TE solar cell is presented in this work. The thermoelectric characterization of p-type Bi₂Te₃ nanowires coated with a photoactive porphyrin layers is studied. We observed charge transfer across the Bi₂Te₃ nanowire-porphyrin interface under white light illumination and the temperature dependence of carriers recombination within the porphyrin. Furthermore, The Seebeck coefficient is substantially increased under illumination indicating that residual charge in the porphyrin modulates the carrier concentration in the nanowires, but the electrical conductivity is not appreciable altered resulting in an enhanced thermoelectric power. Photo-activation of thermoelectric hybrid materials provides an alternative approach to enhance the thermoelectric figure of merit.