Poly(arylene piperidine) Quaternary Ammonium Salts Promoting Stable Long‐Lived Room‐Temperature Phosphorescence in Aqueous Environment

Abstract

attractive applications in organic lightemitting diodes (OLEDs), [2] high-sensitivity chemical sensing, [3,4] space/time-resolved information encryption, [5] high-resolution biological imaging, [6] optical recording, [7] and so forth. [8] Currently, high-efficiency and long-lived RTP materials are primarily limited to inorganic and metal-containing compounds. In particular, the intrinsic disadvantages of metal resources, such as their high cost and complex preparation processes, predominantly hinder their diverse range of applications. [9] Pure organic RTP materials have received considerable attention owing to their superior performance in terms of affordability, adequate biocompatibility, facile modification of functional groups, simple synthesis, and unique features of flexibility, elasticity, and transparency. [10] However, the phosphorescence process initiating from the lowest excited singlet state (S 1 ) to the triplet state (T) through intersystem crossing (ISC), and thereafter, the generated triplet excited state (T 1 ) to the ground state (S 0 ), is spin forbidden. [11] Moreover, the excited triplet state is readily deactivated by nonradiative vibrations and quenched with molecular oxygen. Therefore, the realization of long-lived RTP under atmospheric conditions at room temperature remains a considerable challenge, even in aqueous environments.In recent years, several effective strategies have been employed to improve the spin-orbit coupling (SOC) and suppress the nonradiative decay. For instance, the introduction of heteroatoms such as N, O, S, or aromatic carbonyl groups into organic systems is beneficial for promoting ISC. [12] Furthermore, crystallization, [13,14] host-guest interactions, [15] polymerization, [16] charge separation, [17] and organic-doped inorganic systems [18,19] have been utilized to minimize nonradiative deactivation and stabilize triplet excitons. Ma et al. [20] employed binary copolymerization of diallyl terephthalate and acrylamide to develop amorphous pure organic polymer materials with a phosphorescence lifetime of 537 ms. Yan et al. [21] developed a new smart RTP film that exhibited direct white-light-emitting polarized phosphorescence. The geometric confinement effect and abundant intermolecular hydrogen bonding between the Room-temperature phosphorescence (RTP) materials have garnered considerable research attention owing to their excellent luminescence properties and potential application prospects in anti-counterfeiting, information storage, and optoelectronics. However, several RTP systems are extremely sensitive to humidity, and consequently, the realization of long-lived RTP in water remains a formidable challenge. Herein, a feasible and effective strategy is presented to achieve long-lived polymeric RTP systems, even in an aqueous environment, through doping of synthesized polymeric phosphor PBHDB into a poly(methyl methacrylate) (PMMA) matrix. Compared to the precursor polymer PBN and organic molecule HDBP, a more rigid polymer microenvironment and electrostatic int...

Crystalline matrix-activated spin-forbidden transitions of engineered organic crystals

“…Activating spin-forbidden transitions is vital for almost all photo-electrical related organic/inorganic semiconductive materials or devices in a broad range of applications such as optoelectronics, 1 phosphorescence emitters, 2 photodynamic therapy, 3,4 and photocatalysis. 5 For organic semiconductors, their “dark” triplet state can be lightened and utilized for optoelectronic devices.…”

Amide cluster induced and hydrogen bonding regulated luminescence of linear aliphatic polyamide 1212 with a long alkane chain

“…In addition, the presence of N and O heteroatoms promotes spin–orbit coupling (SOC), the conformational rigidity effectively inhibits non-radiative transitions and stabilizes the triplet state, 60 and the extended electron conjugation in the clusters facilitates the intersystem crossing (ISC) process of the electrons from the singlet states to triplet states, the synergy of which results in the generation of long lasting RTP from PA1212. 75…”

Enabling Long‐Lived Polymeric Room Temperature Phosphorescence Material in Abominable Solvent

“…As the most commonly used polymer matrix, PVA itself contains hydroxyl groups that can form hydrogen bond interactions with phosphors, which greatly inhibits molecular motion and compresses non‐radiative transition pathways. However, the PVA matrix is extremely sensitive to air and humidity, and non‐covalent interactions such as abundant hydrogen bonds and ionic bonds in the matrix are easily decomposed in air or water, resulting in phosphorescence quenching [20] . This means that these RTP materials require strict storage environment and cannot be stored for long periods in atmospheric or even harsher environments.…”

“…However, the PVA matrix is extremely sensitive to air and humidity, and non-covalent interactions such as abundant hydrogen bonds and ionic bonds in the matrix are easily decomposed in air or water, resulting in phosphorescence quenching. [20] This means that these RTP materials require strict storage environment and cannot be stored for long periods in atmospheric or even harsher environments. Hence, to broaden the application range of polymeric RTP materials, it is necessary to develop long-lived RTP materials with good resistance in harsh environments.…”