Conductive ZnMgO Enabling High-Efficiency Wide-Bandgap Photovoltaics

Ascent Solar Technologies (AST) proposes to develop atmospheric pressure chemical vapor deposition (APCVD) of zinc-magnesium-oxide (ZnMgO) as an n-type transparent conducting oxide (TCO) for the top contact that will match the material properties of new buffer and window layers being developed for new wide-bandgap devices. AST’s innovative approach proposes to make the definitive light-absorber layer for high-power, lightweight and flexible thin-film photovoltaics (TFPV). The baseline AST product utilizes single-junction devices with low-bandgap CuInSe2 (CISe) alloys, however better TFPV module performance is predicted through the use of wide-bandgap alloy variations of the CISe based solar absorber. AST has been developing wide-bandgap alloys of CISe based solar absorbers using both aluminum and gallium for simultaneous optimization of the bandgap and material properties. To date, most wide-bandgap device development has used traditional device layers that are optimal for low-bandgap solar absorbers, but are not well matched for wide-bandgap absorbers. In addition, AST will utilize novel lightweight and flexible substrates that are also being developed at AST. Ultra-high TFPV device efficiencies and specific power (> 1500 W/kg) could result from the combined device and substrate technology, exceeding state-of-the-art terrestrial TFPV module efficiencies (at operational temperatures), and enabling terrestrial, spacecraft, balloon and unmanned aircraft technologies.