Ultrathin silicon photovoltaic devices are emerging candidates for the low-cost replacement of thick, wafer-based solar cells. Energy transfer (ET) into thin crystalline silicon substrates from colloidal nanocrystals have been used to increase light absorption and hence electron-hole pair generation in the assembly. Here we demonstrate synthesis of near-infrared lead sulfide/cadmium sulfide core/shell nanocrystal quantum dots (NQDs) with bandgap lower than that of silicon (1.1 eV), suitable for the implementation in hybrid NQD/Si architectures. Optical absorption and emission spectra have shown high luminescence stability of the nanocrystals in solid state geometries. NQDs were drop casted onto Si substrates pre-functionalized with a monolayer of self-assembled ligands (SAMs) to increase its ambient stability and prevent surface oxidation. Using time-resolved photoluminescence (PL) spectroscopy, we have measured kinetics of the NQD donors and found them to become considerably shorter in hybrid geometries, indicating effective interaction with the underlying Si substrate. This study demonstrates the feasibility of an advanced thin-film hybrid solar cell that relies on energy transfer between proximal strong light absorbers and high-mobility Si layers.

Synthesis of PbS/CdS core/shell nanocrystals for emerging optoelectronics applications

251st National Meeting (2016)

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