One‐Step Fabrication of New PCPNs with Unique Optical Responses for Ultra‐Stable Anti‐Counterfeiting Labels

Abstract Constructing a library of stable phosphors with unconventional fluorescence (FL) and room temperature phosphorescence (RTP) color combination is an effective approach to enhance anti‐counterfeiting strength, but remains a challenge. Herein, a one‐step strategy is proposed to fabricate ultra‐stable CsPbX₃/carbon dots (CDs) @NH₄AlP₂O₇ (X = Cl, Br, and I) nanocomposites (PCPNs) with full‐spectrum FL emission and constant short‐wavelength blue RTP emission, breaking the conventional luminescent properties that RTP generally exhibit obvious wavelength red‐shifts compared with FL. The enhanced full‐color (457–612 nm) FL emissions are implemented by adjusting halogen compositions, which is attributed to CsPbX₃ as the dominant FL center. Owing to the RTP emission of CDs, constant long‐lived blue RTP emission lasting 12 s is observed from PCPNs. Additionally, the PCPNs exhibit remarkable tolerance to prolonged ultraviolet irradiation and erosion by solutions with various pH and solvents, supported by NH₄AlP₂O₇ inert shell stabilizing the perovskite structure and triplet state. When the anti‐counterfeiting ink based on PCPNs is printed on various substrates, fine anti‐counterfeiting labels with unconventional emission combinations of FL and RTP are formed and show excellent solvent resistance and mechanical stability. This study provides fresh perspectives on the development of anti‐counterfeiting labels with enhanced security strength and long‐term effects.