Scalable Crystalline Silicon Photovoltaic Fibers for Electronic Textile Applications

This study presents a novel method to fabricate scalable photovoltaic fibers (PVFs) by leveraging crystalline silicon (c‐Si) solar cell technology, known for its high‐power conversion efficiency (PCE), stable performance, and low cost. The c‐Si PVF is built on a flexible circuit strip as narrow as 400 µm, and c‐Si cells as small as 0.35 mm2 are surface‐mounted on the strip. The cells are diced from an interdigitated back‐contact c‐Si solar cell (≈153 cm2). A c‐Si PVF including a 1 mm2 cell reaches PCE up to 9.6% and 11.0% under simulated AM 1.5G illumination without and with encapsulation, respectively, the highest reported for c‐Si PVFs, while a 1.5 ft‐long fiber produces ≈37 mW m−1. Additionally, the PVF can tolerate bending fatigue with no sign of performance loss after 8000 bending cycles. To demonstrate practical applicability, the c‐Si PVFs are also woven into textile swatches. They deliver ≈10 mW cm−2 under a halogen lamp and successfully power a light‐emitting‐diode. This PVF technology is scalable with regards to both achieving thin fibers and its compatibility with roll‐to‐roll fabrication processes. The fiber concept presented here can also be extended to any chip‐scale surface mountable devices, enabling cell‐agnostic fiber technologies for multifunctional electronic textiles. This study presents 1.5 ft‐long encapsulated bendable crystalline silicon photovoltaic fibers with power conversion efficiency up to 11.0% under simulated sunlight, the highest reported for its kind. The fiber is as narrow as 400 µm, scalable in length, and allows interdigitated back‐contact cells to be surface‐mounted on the fibers. A textile made of the fibers produces ≈10 mW cm−2.