Portable and writable photoluminescent chalk for on-site information protection on arbitrary substrates

Information protection is particularly important for secure communication between parties, avoiding the leakage of secret information to unknown parties. Among various strategies used for information protection in the previous reports in the literature, security inks made from photoluminescent materials are the most widely investigated. The security inks suffer from the drawbacks such as lack of universality on various substrates. In this work,...