In Situ Fabrication of Mn‐Doped 2D Perovskite‐Polymer Phosphor Films with Green‐Red Dual Emissions for Yellow Lighting

Abstract 2D metal halide perovskites have emerged as highly bright and stable light emitters, which can be employed as phosphors for optically pumped luminescence devices. However, the intrinsic volatile property is the main weakness to achieve their long‐term lighting applications. Here, an in situ doctor blade method is developed to fabricate a flexible large‐area (20 × 25 cm 2 ) PEA 2 PbI 4 :2Mn‐PVDF film with green‐red dual emissions. Under UV light‐emitting diode (LED) excitation, this yellow phosphor device shows a maximum luminance value of 250 cd m −2 , an extremely large full width at half maximum of 189 nm, and a color coordinate of (0.47, 0.50). The device can pass 120 h of water soaking and 85 °C/85% relative humidity of harsh environment tests, which benefit from the strong interaction of 2D perovskite and hydrophobic PVDF polymer. Different from electroluminescence yellow LED devices, Mn‐doped 2D perovskite‐polymer phosphor films excited by UV LED and fluorescent lamp provide an opportunity to achieve low‐cost indoor yellow lighting in some UV‐sensitive places.