Novel Synthesis of Chalcopyrite Cu_xIn_yS₂ Quantum Dots with Tunable Localized Surface Plasmon Resonances

The burgeoning field of thin film quantum dot photovoltaics has made considerable strides toward efficient and inexpensive forms of third generation solar cells. However, these technologies have largely been based upon toxic metal-containing materials, limiting their foreseeable applications. Here we present a synthesis of nontoxic and stable Cu_xIn_yS₂ quantum dots with tunable size and band gap. Interestingly, this synthesis leads to the presence of a broad-band and size-dependent absorption peak in the infrared (IR), attributed to localized surface plasmon resonances (LSPRs). Due to the sensitivity of their LSPR peak to quantum dot size and solvent refractive index, these quantum dots provide an attractive candidate for tunable plasmon resonance applications. And, if these LSPRs are found to be coupled with excitonic transitions, they may result in sizable increases in photovoltaic efficiency.