Exploring Low Cost and Water Soluble Routes to Quantum Dot Solar Cells

In the world of solar technology, the race is always to find the most efficient and cost effective materials. We are currently exploring the synthesis and characterization of nanometer-sized particles called quantum dots for use in solar materials. Cadmium selenide (CdSe) quantum dots are capable of absorbing light and then either emitting it as fluorescence, an important characteristic for light emitting diodes, or conducting it as photocurrent to adjacent ligands to facilitate charge transfer. Two photofunctional ligands examined were 3-mecapto-1-propane-sulfonate and 4-aminothiophenol. Biphasic reactions where hydrophobic and hydrophilic phases meet at an interface were used to synthesize water-soluble nanoparticles. UV-Vis and fluorescence spectroscopies were used to assess the photophysical qualities of the nanoparticle, and NMR studies were conducted to verify ligand coordination. SEM and AFM explored the surface morphology and the aggregation of nanoparticles. This work on water-soluble ligands is important for ongoing research to include these quantum dots as active chromophores in solar thin films.