Abstract: Efficient light management is essential for enhancing the efficiency of optoelectronic devices, including photovoltaics, light-emitting diodes, and smart displays. To improve devices’ efficiency, researchers have focused on optimizing internal processes. However, effectively coupling external light remains a critical challenge due to optical loss from reflection at interfaces with different refractive indices. To overcome this challenge, achieving a sticker-type anti-reflective (AR) film that ensures both optical and mechanical properties is the simplest, damage-free, and most reliable solution. Here, we developed a sticker-type multi-layer AR (SMAR) film that enhances optical performance and improves surface adhesion without damaging the substrate. The SMAR film exhibits a multi-layer design with a gradual refractive index profile, fabricated by an ethanol-assisted separation method. It significantly improves the transmittance of the polyethylene naphthalate substrate to 94.81% and reduces reflectance to 5.05% (also on glass). These properties were validated through 10,000 cycles of detachment/reattachment and bending tests. In addition, the SMAR film increases the short-circuit current density and improves the power conversion efficiency to 22.61% in flexible perovskite solar cells, one of the optoelectronic devices. Experimental and theoretical results demonstrate that the SMAR film not only enables easy attachment but also ensures superior optical performance and outstanding mechanical robustness for optoelectronic devices.

Key words: Anti-reflective, Sticker-type, Gradual refractive index, Surface adhesion, Optoelectronic devices