Trans‐Reflective Structural Color Filters Assisting Multifunctional‐Integrated Semitransparent Photovoltaic Window

Abstract Multifunction‐integrated semitransparent organic photovoltaic cells (STOPVs), with high power generation, colorful transmittance/reflectance, excellent ultraviolet (UV) protection, and thermal insulation, are fully in line with the concept of architectural aesthetics and photoprotection characteristics for building‐integrated photovoltaic‐window. For the indelible rainbow color photovoltaic window, one crucial issue is to realize the integration of these photons‐ and photoelectric‐related multifunction. Herein, dynamic transmissive and reflective structural color controllable filters, with asymmetrical metal‐insulator‐metal (MIM) configurations (20 nm‐Ag‐HATCN‐30 nm‐Ag) through machine learning, are deliberately designed for colorful STOPV devices. This endows the resultant integrated devices with ≈5% enhanced power conversion efficiency (PCE) than the bare‐STOPVs, gifted UV (300–400 nm) blocking rates as high as 93.5, 94.1, 90.2, and 94.5%, as well as a superior infrared radiation (IR) (700‐1400 nm) rejection approaching 100% for transparent purple‐, blue‐, green‐ and red‐STOPV cells, respectively. Most importantly, benefiting from the photonic recycling effect beyond microcavity resonance wavelength, a reported quantum utilization efficiency (QUE) as high as 80%, is first presented for the transparent‐green‐STOPVs with an ultra‐narrow bandgap of 1.2 eV. These asymmetrical Febry‐Pérot transmissive and reflective structural color filters can also be extended to silicon‐ and perovskite‐based optoelectric devices and make it possible to integrate additional target optical functions for multi‐purpose optoelectric devices.