Luminescent Solar Concentrators utilising aligned CdSe/CdS nanorods

Luminescent Solar Concentrators (LSCs) were originally proposed in the 1970s as a means to reduce the cost of solar energy. LSCs typically consist of a transparent substrate made from PMMA or glass, homogeneously doped with a luminescent species, with solar cells coupled to the edge(s). In this paper CdSe/CdS core/shell nanorods (NRs) are utilized as the luminescent species within luminescent solar concentrator. NRs can be tuned to absorb and emit at different wavelengths by controlling their radial and length dimensions, varying quantum confinement. Additionally, NRs can be aligned, which can reduce light cone losses. The luminescent quantum yield (LQY) of the CdSe/CdS nanorods was found to be unaffected by the high density of nanorods required for alignment, the LQY was measured as 72.4±5% which compares well with literature values. Absorptivity measurements were used to determine that the majority of the nanorods within the thin-film were vertically aligned, with the exception of the nanorods at the edge of the thin-film. The sample was found to have considerably lower absorptivity in the central region, consistent with the presence of vertically aligned CdSe/CdS nanorods which have lower absorptivity in this particular orientation. Finally, the samples optical efficiency was measured to be 7.4±0.5%, which is more than a factor of two higher than the computational derived value of 3.17±0.19% which assumes the CdSe/CdS nanorods emit isotropically.