Si-assisted N, P Co-doped room temperature phosphorescent carbonized polymer Dots: Information Encryption, graphic Anti-counterfeiting and biological imaging

Room temperature phosphorescence (RTP) materials have been widely noticed due to their superior optical properties in the past decade. Herein, we report the Si-assisted N, P co-doped RTP carbonized polymer dots (CPDs), prepared by one-step microwave assisted heating of 3-(2-Aminoethylamino)propyldimethoxymethylsilane and phosphoric acid aqueous solution. The obtained CPDs exhibit bright RTP with an absolute photoluminescence quantum yield 34.17%, absolute phosphorescence quantum yield 11.42% and long lifetime of 1.42 s, which lasts for about 16 s to the naked eyes. We apply the obtained CPDs into information encryption and Polyethyleneterephthalate (PET) film graphic anti-counterfeiting with facile way. Additionally, we make more efforts to realize aqueous RTP CPDs composite. The obtained aqueous CPDs composite exhibits bright aqueous RTP with absolute photoluminescence quantum yield (QY) of 12.61%, absolute phosphorescence quantum yield (QY) of 5.08% and RTP lifetime of 1.46 s, which lasts for about 10 s to the naked eyes. The RTP CPDs composite is nontoxic and biocompatible. These brilliant characteristics allow CPDs composite to be applicable in biological imaging. Thisstudy affords a new RTP material which can be easily prepared and used for information encryption, graphic anti-counterfeiting and biological imaging.