Enhancing Flexible Perovskite Photovoltaic Cells and Modules Through Light‐Trapping and Light‐Shifting Strategies

Abstract Flexible perovskite photovoltaic devices are typically constructed on flexible polyethylene naphthalate (PEN) substrates, which exhibit near‐ultraviolet absorption and high visible‐light reflection, leading to significant optical losses. To address this issue, a reusable optical‐management sticker tailored for flexible substrates has been proposed in this work. The sticker incorporates a light‐shifting material that converts near‐ultraviolet light into visible light, enabling photoelectric conversion of near‐ultraviolet light. Additionally, the sticker features a light‐trapping microstructure that creates a refractive index gradient from PEN to air, thereby achieving a significant anti‐reflection effect. As a result, the efficiency of a flexible perovskite solar cell reached 23.05% (certified 22.46%) under 1 sun AM1.5G illumination and 36.65% (certified 34.03%) under 1000 lux artificial light illumination. Furthermore, scaling this solution to large‐area modules has yielded remarkable improvements, achieving a breakthrough certified efficiency of 20.48% (aperture area 21 cm 2 ) in flexible perovskite photovoltaic modules.