RII Track-4: Digital Alloy Contact Layers for Solar Cells

University Of Vermont & State Agricultural College, Burlington VT

Investigators

Abstract

Non-technical Description Increasing the efficiency of solar energy systems is critical to meeting the nation's future energy needs. This project seeks to address the fundamental problem that a single material is often called upon to perform multiple functions within a solar cell, demanding varying properties within extremely thin films. For this project, the PI and a graduate student will work with the National Renewable Energy Laboratory (NREL) to study the fabrication and characterization of specific thin films and their potential application in solar cells. By controlling the material composition during the fabrication of these films with sub-nanometer resolution, it will be possible to maximize the energy-harvesting efficiency and minimize losses that occur in several solar cell technologies, a critical step in securing our energy future. This proof-of-concept work will build a solid foundation for future collaborative research between the PI's home institution (University of Vermont), the extended renewable energy research community in Vermont, and NREL. Technical Description Pulsed laser deposition (PLD) will be used to construct digital alloy thin films based on ZnO, with dopants (Ga) and isovalent substituents (Mg) to adjust the carrier concentration and bandgap within the film. Because films grown by PLD require multiple laser pulses per monolayer of deposition, we can use target selection to obtain control of the position of the Ga and Mg in the direction of the digital alloy film growth. Collaboration with NREL will allow the construction of thin films that have abrupt, periodic, or gradient physical properties. The project will demonstrate this control and use it to construct selective contact layers for hybrid perovskite solar cells that maximize the carrier collection and minimize recombination at the oxide interface. The expected outcome will be a clear improvement in solar cell performance.