Surface-Engineered Methylammonium Lead Bromide Single Crystals: A Platform for Lifetime-Encoded/Photodetector Double Security Tags

Surface engineering of methylammonium lead bromide (MAPbBr 3 ) single crystals (SCs) is crucial for superior optoelectronics. Herein, we present a surface-engineered crystallization technique in which we in-situ grow a thin polycrystalline MAPbBr 3 layer on the surface of bulk MAPbBr 3 SCs. We have patterned a lifetime-encoded semiconductor-based fluorescence quick response (FLQR) code on the surface using picosecond laser pulse, with a scalability of $3 \times 3$ mm ² . A lifetime-encoded FLQR code integrated with a photodetector can serve as efficient double security tag.