Semitransparent Flexible Perovskite Solar Cells for Potential Greenhouse Applications

Perovskite photovoltaics (PV) is an emerging thin‐film solar energy technology that is advantageous over the currently dominant crystalline silicon PV in terms of its adjustable bandgap with sub‐bandgap transparency, potential flexibility, and more rapid continuous roll‐to‐roll manufacturing, showing promise for unique niche applications. Herein, methylammioun lead tribromide (MAPbBr 3 ) is utilized in a semitransparent flexible solar cell with a transparent electrode using a sandwiched MoO 3 /Au/MoO 3 (MAM) multilayer to harvest around 80% of the visible light region. Through design of the thickness of the MAM multilayer, the reflected light loss is significantly reduced, thereby improving the light transmittance in the visible light region to maximize the photosynthetic yield. The semitransparent flexible device exhibits a power conversion efficiency (PCE) of 7.67% (the highest efficiency of MAPbBr 3 ‐based semitransparent flexible devices), and the opaque rigid MAPbBr 3 solar cell shows a PCE of 9.73% with a high open‐circuit voltage of 1.629 V. Optical measurement demonstrates that the flexible cell without metal electrode shows over 77% transparency in the 540–1100 nm range, whereas the overall semitransparent cell shows an average transmittance of 60% in the 540–760 nm range, which is perfect for greenhouse vegetation to not only act as protective coverage but also provide practical output power.