Rear-Contact Solar Cell with Unstructured Absorber Layer

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This invention relates to a back-contacted solar cell design where the absorber layer is left completely unstructured (i.e., not patterned or etched) and all carrier-selective junctions are heterojunctions rather than homojunctions. The absorber surface is fully covered and passivated by a thin, intrinsically conductive passivation layer, upon which the necessary contact and insulating grids are formed. The design avoids direct contact between the metal contacts and the absorber layer, reducing recombination losses and improving efficiency, while also simplifying manufacturing by eliminating the need for complex patterning of the absorber.

Use CasesContent extracted from patent full text and abstract with AI.

• High-efficiency solar panels for residential and commercial rooftop installations.
• Solar power generation for utility-scale photovoltaic farms.
• Integration into solar-powered consumer electronics or charging devices requiring high power density.
• Solar modules for spacecraft and satellites where efficiency and reliability are critical.
• Building-integrated photovoltaics (BIPV) utilizing aesthetic and high-performance solar solutions.

BenefitsContent extracted from patent full text and abstract with AI.

• Greatly reduced recombination losses and increased solar cell efficiency due to exclusive use of heterojunctions and superior passivation.
• Elimination of absorber layer structuring simplifies manufacturing and reduces risk of surface damage, thus improving cell reliability and yield.
• No front-side contacts, so there are no shadowing losses, allowing more light to reach the active area and further boosting current output.
• Flexibility in material selection and cell architecture, compatible with both wafer-based and thin-film solar technologies.
• Improved process robustness and reduced requirements for alignment and masking, leading to lower production costs.

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Patent Abstract

Back contact solar cells do not have shadow losses. However, the required structuring measures impair the bounding surface of the absorber layer, which must be well passivated, in the case of homojunctions. The solar cell (01) according to the invention has only heterojunctions (14, 17). The doped absorber layer (02) is well passivated by an intrinsically conductive passivation layer (15) covering the entire surface and completely unstructured. A contact grid (08), an insulating grid (09) congruent therewith, an emitter layer (07), and a contact surface (13) are arranged on the intrinsically conductive passivation layer (15). In order to support the discharge of charge carriers, the intrinsically conductive passivation layer (15) is made of a material having a high surface charge opposed to the doping of the absorber layer (02). Furthermore, a supporting potential barrier between the intrinsically conductive passivation layer (15) and the contact grid (08) and a sufficient overlap width (L) in the sense of an overlap of the contact elements (11) of the contact grid (08) with insulation elements (18) of the insulation grid (09) are provided in order to avoid internal cell short circuits. Because the absorber layer (02) is completely unstructured, and because of the exclusive heterojunctions (14, 17) thereof, a high efficiency can be obtained in the generation of electricity.