Exploiting Nanophotonic Effects To Enhance The Performance Of State-Of-The-Art Photocatalytic And Photovoltaic Devices

2018-08-16 Prof. Karthik Shankar, Department of Electrical and Computer Engineering, Universi

ABSTRACT :

Although single junction halide perovskite solar cells have demonstrated photoconversion efficiencies (PCEs) of up to 22 % (with efficiencies of 17 % routinely reported), there remains further room for improvement in the open circuit voltages (Voc) and short circuit current densities (Jsc) achievable. It has been shown that material quality no longer constrains performance in the best performing halide perovskite solar cells, rather it is inefficiencies in the management of photons that are the largest source of losses in Jsc and Voc due to poor harvesting of photons near the semiconductor band-edge, non-radiative carrier recombination losses limiting the match of the solar cell to a black body radiator at the same temperature, poorly optimized angular distribution of emission due to radiative recombination of carriers, and changes in the entropy of photons. In this talk, the use of active layer light management through the use of 1D metal oxide nanophotonic architectures to overcome these losses will be discussed. High performance photocatalysts need to make optimal use of incident light to drive chemical reactions. Photonic crystals are materials consisting of microscale- and submicron-scale periodicity in their refractive index wherein the propagation of light is prohibited in a certain frequency band (called the photonic stop-band). When pi-conjugated molecules or quantum dots are introduced into a photonic crystal whose absorption profile matches the photonic stop band, very strong absorption can result in such defect-doped photonic crystals, which is useful for photocatalysis. Likewise, nanoscale- and submicron-scale noble metal structures exhibit strong surface plasmon resonances (SPR) that result in an amplification of the local field and the generation of energetic carriers called “hot electrons”. The exploitation of SPR in photocatalysis forms the basis for the rapidly expanding field of plasmonic photocatalysis. In this talk, our latest results on the use of 1D metal oxide nanophotonic architectures to achieve high rate CO2 photoreduction and photoelectrochemical water-splitting will be presented.

Event Name

Seminars

Place

S N Bose Hall (HSB 210)

Start Time

15:00

End Time

16:00

External Link

PDF to Talk