Grant: Discovery Grants Program - Individual

The proposed research involves the fabrication and characterization of luminescent materials which modify the solar spectrum, and thereby have potential to enhance the efficiency of solar cells. A fundamental efficiency limitation of solar cells is that they are not able to utilize photons with energy less than their energy band-gap, and photons with energy greater than this band-gap use only part of their energy to create electric current: the rest is converted into heat. A solution to this problem is to adapt the solar spectrum to the solar cell. This can be achieved by converting two photons of sub-band-gap energy to a photon of energy above the band-gap (up-conversion), or by converting a photon with energy well above the band-gap to two (or more) photons still above the band-gap (down-conversion). Either method for this latter solution has significant potential to enhance solar cell efficiency above theoretical efficiency limits. The project investigates the potential of using lanthanide-doped materials to implement up-conversion and down-conversion for solar cells. While lanthanide ions possess many advantages for efficient spectral conversion, they tend to absorb photons over narrow spectral ranges, and their absolute absorption strength is relatively weak. To improve the impact of converting the solar spectrum, work shall be particularly focused on sensitizing the up-conversion and down-conversion processes with absorbers which efficiently absorb solar radiation over a wide spectral range, and transfer this energy to spectrally-converting lanthanide ions. Highly qualified personnel will be trained in the fabrication of sensitized lanthanide-doped bulk and nano-structured materials, as well as their investigation using time-resolved luminescence techniques. Optimal materials for conversion of the solar spectrum will be incorporated into solar cells, wherein proof-of-principle experiments will be conducted to demonstrate enhancement of solar cell efficiency. Significant enhancement of photovoltaic device efficiency will pave the way to a more efficient alternative energy source.