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Tunable Nanocrystalline CZTS for Solar Photovoltaics with No Required Annealing

Colorado State University

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PDF Document PublicationNanocrystal Summary (230 KB)

Example solar cell
Example solar cell

Technology Marketing Summary

Thin-film solar cells are expected to replace the current first generation of solar photovoltaic technology due to their lower manufacturing cost and increased electrical output. Nanocrystal cells, one of the second generation of solar photovoltaics, offer the advantage of tunable optical and electrical properties, allowing manufacturers to optimize the cell’s power output. Although these cells offer many advantages, current forms of the technology must be annealed in order to increase electrical conductivity. This annealing process removes manufacturers’ abilities to tune the nanocrystals and greatly increases manufacturing costs.


Researchers in the Chemistry department at Colorado State University have recently created a novel synthesis method for nanocrystal solar photovoltaic technology to produce cells with increased electrical conductivity that do not require annealing. This novel technology utilizes the Cu2ZnSnS4 (CZTS) nanocrystal with selenium added to afford manufacturers exceptional control over the ratio of selenium to sulphur. These nanocrystals retain the tunable optical and electrical properties associated with similar pre-annealing cells. The cell’s band gap can be tuned by varying the ratio of selenium to sulphur atoms in the nanocrystal, resulting in cells that are optimized to create as much energy as possible from sunlight. This technology also reduces trap states, which permits more efficient charge transport within the cell without annealing.

This technology will be of particular interest to solar photovoltaics manufacturers looking to produce the next generation of cheaper, more efficient solar cells. The nanocrystals are comprised of abundant elements, in contrast to first-generation cells made of rarer, and therefore more expensive, elements. Eliminating the annealing process enables unprecedented control of the sulphur-selenium ratio and also reduces the manufacturing cost, allowing these solar cells to better compete with fossil fuels in electricity generation.

  • Tunable structural, optical, electrical, and defect properties
  • No expensive annealing process required
  • Simple, low-temperature nanocrystal deposition onto substrate
  • Nanocrystals are made from cheaper, more abundant elements
Applications and Industries
  • Thin-film solar photovoltaic cells
More InformationSee related technology 12-059 ("Inorganic Shells for CZTS Nanocrystals With Enhanced Charge Transport Capabilities").Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
12-050Prototype - Laboratory-scale prototypes successfulAvailable - Provisional patent pending07/26/201207/26/2012

Contact CSU About This Technology

To: Jeremy Nelson<>