Highly stable perovskite nanogels as inks for multicolor luminescent authentication applications

Preparation of multiplexing optical tags with well-resolved emissions is particularly intriguing in anti-counterfeiting and authentication applications given that broad and overlapping emission would severely impair the encoding capacities and performance. Bright and sharp multicolor emission of metal halide perovskite quantum dots (PQDs) makes them good alternatives, but the weak stability potentially hampers their practical implications. We here developed a novel strategy for synthesizing a full-spectral emissive perovskite gel with greatly improved photo-stability, thermal-stability and humidity-stability by embedding PQDs in a pre-polymerized polymer gel at room temperature and further employed it as multicolor ink for printing anti-counterfeiting two-dimensional barcodes.