Research on Long-Lived Room-Temperature Phosphorescence of Carbazole-Naphthalimide Polylactides

• Main Authors: Zhiwei Li, Xingyuan Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Polymers
• Subjects: polymer long-lived room temperature phosphorescence (RTP); donor-acceptor; intersystem crossing; charge-transfer state; red RTP
• Online Access: https://www.mdpi.com/2073-4360/12/4/790

Two types of naphthalimide derivatives were synthesized by introducing a carbazole group and an n-butyl, respectively, into the naphthalimide system. The electron-donating ability of two kinds of derivatives was investigated by the electrochemical method. These two types of derivatives were used as initiators for the polymerization of <span style="font-variant: small-caps;">d</span> and <span style="font-variant: small-caps;">l</span>-lactide polymerization. Here, the emission and UV-vis absorption serve as the main focus. Compared with solely donor-initiated polylactide (PLA), the PLA with a donor-acceptor structure has a more efficient phosphorescence emission, of which the longest phosphorescence lifetime is up to 407 ms. The experimental results reveal the existence of charge-transfer states in the donor-acceptor-ended polymer. Due to the role of charge-transfer states, a red phosphorescent polymer was developed. Theoretically, these desirable advantages render synthesized PLAs a potential candidate for bioimaging and anti-counterfeiting.