[nanoPost] Printable semiconductor

Company USA

A thin film of Copper-Indium-Gallium-Diselenide (CIGS) can simply be printed (solution-coated) to create an efficient solar cell with unprecedented yield, materials utilization, and throughput.

Conventionally, CIGS thin-film solar cells have been fabricated with vacuum deposition techniques such as sputtering or evaporation.  While such vacuum techniques work well for producing small CIGS cells in a laboratory, the process cost of these techniques is so high that the result is not an inexpensive cell relative to the per-square-meter economics that the solar industry requires.

Printing is by far the simplest and most robust technique for depositing thin films. But, of course, this would require a CIGS ink to print, and such a breakthrough ink, composed of nanoparticles of CIGS material, would require solving an entire array of fundamental science challenges. 

 
One key advantage of a printable CIGS ink is that one can print it just where one wants it to be, that is, avoid waste of expensive semiconductor material.  This is in contrast to vacuum processes whose materials utilization tends to be as low as only 30% in highly optimized production implementations by leading companies.

Furthermore, the development of a CIGS ink solves a particularly thorny challenge specific to CIGS: simply by virtue of the particles being mixed in the right overall amounts, one can ensure that the proper atomic ratios of the CIGS elements are guaranteed wherever the ink is printed, even across large areas. This contrasts to vacuum deposition where, due to the unusual and complex four-element nature of CIGS, one has to basically "atomically" synchronize various materials sources -- a challenge with no successful precedent in any industry on a repeatable high-yield production-scale basis.