Emission mechanism understanding and tunable persistent room temperature phosphorescence of amorphous nonaromatic polymers. (18th December 2018)

• Record Type: Journal Article
• Authors: Zhou, Qing; Wang, Ziyi; Dou, Xueyu; Wang, Yunzhong; Liu, Saier; Zhang, Yongming; Yuan, Wang Zhang
• Is Part Of: Materials chemistry frontiers. Volume 3:Number 2(2019)
• Page Start: 257
• Page End: 264
• Publication Date: 2018-12-18
• Subjects: Materials science -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1039/c8qm00528a
• Languages: English
• ISSNs: 2052-1529

Abstract

Abstract : Intrinsic emission and persistent room temperature phosphorescence from amorphous nonaromatic polymers are observed, which can be well rationalized by the CTE mechanism. Abstract : Deciphering the emission mechanism of nonconventional luminogens and achieving persistent room temperature phosphorescence (p-RTP) from pure organic compounds have drawn increasing attention due to their significant fundamental importance and promising applications. Previous reports on nonconventional luminogens, however, mainly focus on fluorescence, while advances in pure organic p-RTP are generally restricted to aromatic crystals or host–guest systems. Herein, we report the unique intrinsic emission and moreover p-RTP in amorphous nonaromatic polymers of poly(acrylic acid) (PAA), polyacrylamide (PAM) and poly( N -isopropylacrylamide) (PNIPAM). These polymers are nonluminescent in dilute solutions, while being highly emissive in concentrated solutions, nanosuspensions and solid powders/films. This can be rationalized by the clustering-triggered emission (CTE) mechanism, as supported by further thermoresponsive emission, cryogenic and aggregation-induced emission (AIE) experiments, alongside single crystal analysis. Furthermore, PAA and PAM solids under ambient conditions, and PNIPAM solids under vacuum or under nitrogen, demonstrate distinct p-RTP, which can be enhanced through further ionization or pressurization. These results not only refresh our understanding of the emission mechanism of nonaromatic polymers, but also enable the facile fabrication and application of pure organic p-RTP luminogens from readily available compounds, thus providing an important step forward in both nonconventional luminogens and p-RTP.