Enabling High Operational Efficiencies with Mid-Bandgap AgCIGS on Modified High-Temperature Capable, Lightweight and Flexible PBO Substrates

ABSTRACT: This phase I project will develop and merge the different technologies to reduce the defect-density of mid-bandgap (1.4 eV) chalcopyrite based solar absorbers to enable>15% efficient modules (at standard test conditions) on lightweight and flexible polymer substrates. As an added benefit, the mid-bandgap device will improve the performance of CIGS-based devices for space applications by enable 30% higher performance at nominal operational temperatures due to lower temperature coefficients and reduced joule-heating losses. The defect-density reducing technologies that will be developed are listed as follows: 1) Higher-temperature capable PBO polymer substrates enabling higher processing temperatures (>600degreesC), 2) Higher conductivity and stress reducing back contact structures enabling lower stress solar absorbers and 3) Ag alloying in mid-bandgap CIGS solar absorbers. Each of these approaches have been demonstrated to reduce defects and will be merged for the first time under this proposed project while leveraging earlier development with the individual components. BENEFIT: We have a natural evolution of our product development through R & D, Roll-to-roll Prototype, 1.5MW Production, 25MW production, and beyond. Commercialization of the mid-bandgap devices will be marked by demonstration on the 1.5MW facility, but materials for evaluation will be available much sooner, namely when demonstrated on the prototype line. Mid-bandgap modules with High-T substrates will likely represent the second or third generation of product from AST, the first being baseline single-junction CIGS. Our customers for this product will be defense agencies/contractors (space and satellite power, near space reconnaissance, battle field power solutions packs, solar powered tents, portable power), power electronics OEMs, building material solution providers, and PV system integrators for both the commercial and residential building product markets. Our lightweight, high specific power product can be incorporated into fabric, structural composites, and polymeric circuitry to present advantages over ultra-high efficiency expensive multijunction PV. We will be able to demonstrate this technology on the 1.5MW line and gain experience with the higher-performance products. Phase II work of this project will feed directly into pre-production demonstration and process validation. Given a nominal one to two-year gestation of the product, we can expect a device achieving true commercialization sometime after 2012.