Integration of Laser–Patterned Photonic Crystals in Si Solar Cells

article
2025
authors
Rienäcker, Michael and Römer, Udo and Krügener, Jan and Maksimovic, Jovan and Katkus, Tomas and Stonytė, Dominyka and Ng, Soon Hock and Mu, Haoran and An Le, Nguyen Hoai and Khajehsaeidimahabadi, Zahra and Seniutinas, Gediminas and Baltrukonis, Justas and Ulcinas, Orestas and Mikutis, Mindaugas and Sabonis, Vytautas and Nishijima, Yoshiaki and John, Sajeev and Juodkazis, Saulius and Peibst, Robby and An Le, Nguyen Hoai
journal
Advanced Optical Materials
doi:10.1002/adom.202501781

abstract

Photonic crystal (PhC) light trapping is predicted to enhance absorption beyond the Lambertian limit, potentially increasing silicon solar cell efficiencies above 28%. However, integrating PhC structures into high-efficiency devices at scale remains challenging. PhC textures are integrated into back-contacted silicon solar cells by combining femtosecond laser ablation of alumina masks with dry etching. Excellent surface passivation is maintained using an isotropic defect-removal process based on ammonia peroxide mixture (APM). This preserves the front-side texture and keeps optical reflection low. The PhC-patterned cells deliver minority carrier lifetimes and carrier collection efficiencies comparable to state-of-the-art high efficiency devices. A certified efficiency of 23.1% is achieved. The quantum efficiency of the thick (190–290 μm) solar cells, however, shows no clear wave-optical resonances under standard conditions, despite the high structural and electronic quality. Scalability is improved by applying direct laser writing with Gaussian and Bessel beams and developing a periodically anchored mask design. This enables uniform, large-area patterning. These advancements mark a key step toward the practical implementation of PhC-enhanced silicon photovoltaics.