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Hot Electron Photovoltaics Using Low Cost Materials and Simple Cell Design

Stage: Development
"Third-generation" PV technologies are being actively pursued in academic research labs. These include nano-optics, multi-junction architectures, multi-exciton, plasmonics, and lower cost tandem cells. The goal is a module cost of less than $0.60/watt. Many of these technologies are in exploratory or early research stages but still can be evaluated according to their material requirements, processing complexity, and potential scalability. For example, concepts that utilize GaAs or CIGS may have cost issues or material availability issues. Similarly, complex cell designs or designs that feature nano-architectures such as quantum wires may not be easily scaled.

Robert Kostecki and Sam Mao of Berkeley Lab have invented a new approach to affordable, third generation PV. The technology builds upon previous research that uses surface chemical reactions to generate and inject hot electrons into a metal catalyst. In the recent invention, light is absorbed by the PV material and hot electrons are generated. Charges are then separated across a Schottky barrier.

The technology is a simple, low cost, scalable solution that addresses the concerns of high cost materials, materials availability and toxicity, complexity of cell design, and large-scale manufacturability. It relies on cheap, abundant materials that do not require ultra-high purity processing. Various existing deposition technologies can be used for cell manufacturing, none of which rely on ultra-high vacuum or expensive MOCVD/MBE equipment. Based on the initial laboratory conceptual demonstration, greater than 10% efficiency is projected with process development on existing tool sets. The technology uses a simple cell design that, together with the processing flexibility, should provide a path to scalable manufacturing.

Applications and Industries

  • Low cost PV technology


  • Abundant, low cost materials
  • Simple cell design
  • Compatible with various deposition techniques