Paper EN+NS-MoM5
Quantum-Confined Nanocrystals as Building Blocks for Low-Cost Solution-Processed Multi-Junction Solar Cells

Monday, October 29, 2012, 9:40 am, Room 15

In light of recent advances in synthesis, characterization, and the emerging understanding of their size-dependent properties, there are many exciting opportunities for semiconductor nanomaterials to contribute to the development of next-generation energy conversion technologies. Semiconductor nanocrystal quantum dots are particularly attractive material candidates for the efficient capture of solar emission in inexpensive, thin film photovoltaic devices due to their large absorption cross sections, low-cost solution-phase processing and size-tunable energy gaps. The prospect of exploiting colloidal nanostructures for the creation of low-cost multi-junction solar cells has garnered immense scientific and technological interest. We recently demonstrated demonstrate solution-processed tandem solar cells created from nanocrystal quantum dots with size-tuned energy levels. Bringing this prospect to fruition requires the connection of absorber layers with cascaded energy gaps subject to stringent electrical and optical constraints. We show that interlayers composed of ZnO/Au/PEDOT provide appropriate carrier density and energy-level alignment to resolve this challenge. With such interlayers we have been able to create nanocrystal quantum dot tandem cells that exhibit IR sensitivity and a open circuit voltage approaching 1V. These advances provide guidelines for the design of an effective interlayer in tandem cell devices and suggest a promising future for solution-processed nanocrystal quantum dot solar cells.