Project Name: Wide-Bandgap Polycrystalline III-Vs as Transparent, Carrier-Selective Heterojunction Contacts for Silicon Photovoltaics
Funding Opportunity: Solar Energy Technologies Office Fiscal Year 2018 Funding Program (SETO FY2018)
SETO Research Team: Photovoltaics
Location: Urbana, IL
SETO Award Amount: $200,000
Awardee Cost Share: $50,000
Principal Investigator: Minjoo Lee
-- Award and cost share amounts are subject to change pending negotiations --
This project team will investigate increasing the efficiency of silicon solar cells by replacing a layer of doped silicon, which is silicon that contains added elements, with a layer of III-V materials, so named because they are made of elements from the third and fifth groups of the periodic table. In current silicon heterojunction cells, a layer of doped silicon absorbs some sunlight before it can reach the interior of the cell, which reduces the voltage the cell can produce.
The team will use silicon solar cells with heterojunction, or non-silicon, layers to extract voltage from the cells, and will grow layers of two types of heavily doped III-V crystals, aluminum gallium phosphide and aluminum indium phosphide, on silicon solar cells. These two materials are transparent to visible light, so they will allow light to pass through the top layer, enabling maximum absorption by the silicon. The team will study the effects of different amounts of doping in these layers and any defects within the cell. They will identify the III-V layers that demonstrate the most promise for increasing silicon HJ cell efficiency and then build heterojunction cells with those layers.
This project will enable more light to reach the internal silicon wafer that is the bulk of the cell, leading to higher efficiencies and getting closer to the full potential of silicon heterojunction cells. The team’s findings will be used to inform future projects that will explore pathways to large-scale manufacturing of higher-efficiency solar cells.