This Small Business Technology Transfer Phase I project will demonstrate the commercial feasibil-ity of metal oxide nanostructures, especially ZnO and TiO2, which offer unprecedented properties, suitable for a wide range of applications from thin film battery and LED to gas sensors. In particu-lar, they have a potential to replace indium tin oxide (ITO) as a transparent electrode and as an electron-acceptor material in bulk heterojunction solar cells. Furthermore, with proper design of nanostructures, it is possible to ?tune? into controllable and multi-functional properties, for example, either continuous film for transparent electrode or mesoscopic porous structure for bulk hetero-juction solar cells. While these materials are prepared by expensive vacuum processes today, there is a tremendous need to develop a cost-effective, roll-to-roll processing. We propose to develop solution-based processing enhanced by laser processing to meet this target. The advantages of this hybrid approach are; (1) laser sintering, curing and/or annealing improve the morphology, structure and chemistry of printed precursor materials, to fine-tune the property of nanostructures, (2) pat-terning is achieved by laser selective sintering and/or direct-write process, (3) local energy deposi-tion of laser allows selective modification of desired material with minimum thermal influence, thus compatible with low-cost plastic substrates.
Impact of this project is far reaching, since the transparent electronics is used in day-to-day applica-tions such as LCD displays, touch screens, and solar cells. If successful, the outcome of this project will have a significant impact to the reduction to practice and the mass production of these devices. First, the current choice of transparent conductor, ITO, relies on the diminishing supply of natural resource, indium. On the other hand, ZnO and TiO2 are inexpensive, abundant, biocompatible, non-toxic, chemically stable, and easy to prepare. Second, the use of low-cost material such as ZnO and the cost-effective production solutions developed in this project will help significantly to achieve grid parity when applied to the manufacturing of solar cells. It would also reduce America?s dependence on foreign oil and reduces greenhouse gas emissions, saving the environment. Furthermore, ZnO and other metal oxide materials and their nanostructures have a potential to create new applications as porous nanostructures are useful in many applications beyond electronics, ranging from water treatment to sensors and fuel cells. In addition, this project will enhance the front-end scientific understanding of nanomaterials growth and interaction with laser beam.