Solar cells formed via aluminum electroplating
AssigneeArizona Board of Regents on behalf of Arizona State University
InventorsMeng Tao, Wen-Cheng Sun, Xiaofei Han
Life of this patent
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Abstract
Electroplating of aluminum may be utilized to form electrodes for solar cells. In contrast to expensive silver electrodes, aluminum allows for reduced cell cost and addresses the problem of material scarcity. In contrast to copper electrodes which typically require barrier layers, aluminum allows for simplified cell structures and fabrication steps. In the solar cells, point contacts may be utilized in the backside electrodes for increased efficiency. Solar cells formed in accordance with the present disclosure enable large-scale and cost-effective deployment of solar photovoltaic systems.
Claims19
A method for electroplating of aluminum onto silicon, comprising:
- preparing an ionic liquid comprising aluminum chloride and an organic halide, the ionic liquid having a molar ratio of aluminum chloride:organic halide greater than 1;
- pre-baking the ionic liquid at a temperature of between 100 degrees Celsius and 200 degrees Celsius for a period of between 30 minutes and 90 minutes to drive out residual moisture in the ionic liquid;
- cleaning a silicon substrate with at least one of hydrogen fluoride, hydrogen chloride, hydrogen peroxide, or ammonia hydroxide;
- depositing at least one of nickel or titanium onto a first side of the silicon substrate via a galvanostatic electroplating process forming a first layer of nickel or titanium, wherein the first layer of nickel or titanium has a thickness of between about 50 nanometers and about 99 nanometers and reduces the resistance of the silicon substrate or facilitates the adhesion of aluminum;
- depositing aluminum onto the first layer of nickel or titanium via a galvanostatic electroplating process incorporating the ionic liquid, wherein the depositing is performed with the ionic liquid at a temperature of between 111 degrees Celsius and 150 degrees Celsius;
- cleaning the silicon substrate with alcohol and deionized water;
- annealing the silicon substrate to reduce the resistivity of the electroplated aluminum;
- storing the ionic liquid under dry nitrogen in a dry nitrogen glove box;
- and
- reusing the ionic liquid to electroplate a second silicon substrate.
Dependencies are inferred from the claim text.