BACKGROUND:  Inorganic materials synthesized for photovoltaic applications generally have high efficiencies, more than those seen with organic materials, but they typically have high manufacturing costs associated with them. Ternary nanocrystals are a class of materials identified for their use in high efficiency photovoltaics that overcome many of these high manufacturing costs by their ability to be synthesized as nanoparticles and colloids. However, previous syntheses of ternary nanocrystals as colloids are complicated and limited in their control over the final products.

INNOVATION:  The researchers have developed a method to produce colloids of the ternary nanocrystal Cu-In-S through an all-solution process. This technique allows control over the composition ratio and the ability to determine the crystalline structure, which was previously unattainable with colloidal syntheses of these materials. In addition, the bandgaps of the materials have tunable absorption from visible through to IR wavelengths. The invention enables low-cost fabrication of inorganic photovoltaics as well as the printing and patterning of nanowires.

POTENTIAL APPLICATIONS 

• High efficiency, inorganic solar cells
• High-aspect ratio nanowires
• Thin-film field-effect transistors (TFTs & FETs)

ADVANTAGES

• Solution based route to colloidal ternary nanocrystals
• Tunable synthesis provides control over composition, bandgap, absorption spectrum, crystalline structure, and nanoparticle size
• Patterning of high aspect ratio nanowires via spin-coating or printing
• A platform wet-chemistry reactor for scale up manufacturing
• Enable low cost processing techniques to be used for inorganic solar cell fabrication

DEVELOPMENT-TO-DATE:  Developed method to manufacture materials, device fabrication underway. The method has been demonstrated for copper, indium, gallium, and sulfide.

Related Papers (Selected)

• Daocheng Pan, Lijia An, Zhongming Sun, William Hou, Yang Yang, Zhengzhong Yang, and Yunfeng Lu, "Synthesis of Cu-In-S ternary nanocrystals with tunable structure and composition," J Am Chem Soc. 130 (17), 5620-5621, 2008 [more]

Reference: UCLA Case No. 2008-608