684643 event 1757357124 1757357201 <![CDATA[Ph.D. Proposal Oral Exam - Wookjin Choi]]> Title:  High-efficiency Tunnel Oxide Passivated Contact Solar Cells using Advanced Structures and Technologies

Committee:

Dr. Rohatgi, Advisor

Dr. Graber, Chair

Dr. Gaylord

]]> The objective of this research is to develop cost-effective, high-efficiency crystalline silicon (c-Si) solar cells by integrating Tunnel Oxide Passivated Contact (TOPCon) technology into advanced device architectures. Current solar cell performance is primarily limited by recombination and resistive losses at metal-Si contact interface. The proposed work addresses these challenges through the implementation of TOPCon technology, fundamental understanding, detailed material characterization, comprehensive device modeling and novel process solutions. High-efficiency, large-area solar cells will be fabricated to demonstrate the commercial readiness of these advanced TOPCon solar cells. A key aspect of achieving high efficiency is reducing the reverse saturation current density (J0) and the contact resistivity (ρc) at the metal-Si interface, enhancing both the open-circuit voltage (Voc), and fill factor (FF). This research will specifically focus on the following tasks: (1) Establishing a quantitative framework to correlate carrier selectivity to solar cell efficiency, identifying a pathway toward high-efficiency TOPCon-based solar cells; (2) Developing a p-type TOPCon solar cell with highly a highly efficient hole-selective TOPCon layer, replacing traditional Al-alloyed hole contacts in current main stream Passivated Emitter and Rear Contact (PERC) cells; (3) Developing a novel double-side TOPCon solar cell structure featuring electron- and hole- selective TOPCon layers on both sides to maximize the potential of TOPCon technology; and (4) Conducting a preliminary investigation into integrating the TOPCon technology into an Interdigitated Back Contact (IBC) architecture, regarded as the ultimate c-Si solar cell architecture due to its highest efficiency potential.

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