Polymeric Hole-Selective Contact for Crystalline Silicon Solar Cells

Carrier-selective contacts based on inorganic materials (e.g., silicon layers and metal oxides) have been intensively investigated for efficient crystalline silicon (c-Si) photovoltaics. Compared to the vacuum deposition process for inorganic films, organic semiconductors offer a simplified and low-cost processing. Herein, solution-processed poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA) is developed as hole-selective contact for c-Si solar cells. PTAA exhibits a suitable band alignment with p-type c-Si, featuring a small valence band offset (approximate to 0.1 eV) and a large conduction band offset (approximate to 2.2 eV) for effective electron blocking. PTAA combined with Al2O3 passivation interlayer is demonstrated to simultaneously offer a low contact resistivity (36.5 m omega cm2) and a moderate surface passivation (implied open-circuit voltage 635.6 mV) on p-type c-Si surface. By the implementation of a full-area hole-selective Al2O3/PTAA rear contact, a champion efficiency of 20.2% is achieved on the hybrid c-Si solar cells. Herein, a guiding principle for future research on polymeric carrier-selective contact for c-Si solar cells is provided. A low-cost and high-performance poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine]-based contact for silicon solar cells is reported. After insertion of an ultrathin Al2O3 interlayer, which acts as a surface passivating layer, a silicon solar cell with an efficiency of 20.2% is achieved using a simplified fabrication process. Herein, a guiding principle for organic polymer in crystalline silicon solar cells is provided.image (c) 2023 WILEY-VCH GmbH