Room Temperature Phosphorescence from Intermolecular Hydrogen-Bonded Quinolone Quinoline Carboxylic Acid/Polyacrylamide Material and the Application for Anti-Counterfeiting

Polymer-based organic room temperature phosphorescence (RTP) materials are of critical importance in organic light-emitting diodes, displays, and anti-counterfeiting applications. Nevertheless, the development of heavy-atom-free materials that exhibit long RTP lifetimes and high quantum yields via a straightforward, cost-effective, and environmentally friendly preparation remains a significant challenge. In this study, we design and construct an environmentally sustainable and highly efficient hydrogen-bonding network (QA/PAM) employing commercially available quinoline carboxylic acid (QA) derivatives and the water-soluble polymer polyacrylamide (PAM) with high hydrogen bond capacity. By increasing the conjugation degree and the number of carboxyl groups in QA, we can effectively enhance the π-π* and n-π* transitions, thereby reducing the energy gap between the S1 and T1 states, resulting in high quantum yields and offering the ability to adjust colors from blue to green and subsequently to yellow-green. Particularly, BQDA/PAM-0.3 wt% system shows an average lifetime of 392.46 ms and QY of 26.93% under 300 nm excitation at 297 K. Anti-counterfeiting patterns and 2D code fabricated by the BQDA/PAM solution by environmentally friendly screen printing can be facilely deciphered by mobile phone, offering potential applications in optical and digital information security for commercial production.