Persistent room-temperature phosphorescence (p-RTP) has drawn extensive attention due to its unique photophysical processes and promising applications in organic light-emitting diodes (OLEDs), [1] biological areas, [2] chemical sensors, [3] optics, [4] and anticounterfeiting technology. [5] Currently, p-RTP systems, however, are normally restricted to inorganic compounds. [6] As promising alternatives, pure organic p-RTP luminogens take advantages of low cost, wide variety, environmental friendliness, good biocompatibility, appreciable stability, and good processability, [7] allowing a wide range of optoelectronic and biological applications. [2] The triplet excitons of organic luminogens, however, are prone to nonradiative relaxations through vibrational stretching and external quenching (i.e., O 2 ), making it difficult to achieve efficient p-RTP. [8] To overcome such barriers, generally, two attempts are endeavored: one is to boost the spin-orbital coupling (SOC) and subsequently promote the intersystem crossing (ISC) processes through incorporation of heavy atoms, [9] heteroatoms, [10] or aromatic carbonyls; [11] the other is to stabilize the triplet excitons in a rigid environment by suppressing nonradiative decay pathways to activate the RTP emission, [12] such as crystal formation, [13] embedding into rigid hosts, [14] polymer assistance, [15] and metal-organic framework (MOF) coordination. [16] Despite exciting advancements have been made in the past few years, fabrication of efficient and robust p-RTP still remains a challenge. First, the p-RTP efficiency (Φ p ) of reported phosphors with the lifetime (〈τ〉 p ) of several hundred milliseconds are generally below 5%, [11a,13a] and moreover, robust p-RTP at complex and changing environments is rare, even though it is essential for diverse applications in data recording, encryption, anticounterfeiting, and bioimaging. [17] For example, when applied in molecular imaging, owing to their long-lasting nature, p-RTP materials can eliminate the need for light irradiation and circumvent the troublesome interference of nanosecond tissue autofluorescence, thus permitting much clearer and more reliable bioimaging with high signal-to-noise ratios. Current methodologies toward biomedical applications, however, mainly adopt nanocrystallization or top-down nanoparticle Pure organic persistent room-temperature phosphorescence (p-RTP) under ambient conditions is attractive but challenging due to the slow intersystem crossing process and susceptibility of triplet excitons. Fabrication of pure organic RTP luminogens with simultaneously high efficiency and ultralong lifetime still remains a daunting job, owing to their conflicting requirements for the T 1 nature of (n,π*) and (π,π*) characteristics, respectively. Herein, a group of amide-based derivatives with efficient p-RTP is developed through the incorporation of spin-orbital-coupling-promoting groups of carbonyl and aromatic π units, giving impressive p-RTP with lifetime and efficiency of up to 710.6 ms and 10.2%,...

It is a textbook knowledge that protein photoluminescence stems from the three aromatic amino acid residues of tryptophan(Trp), tyrosine (Tyr), and phenylalanine (Phe), with predominant contributions from Trp. Recently, inspired by the intrinsic emission of nonaromatic amino acids and poly(amino acids) in concentrated solutions and solids, we revisited protein light emission using bovine serum albumin (BSA) as a model. BSA is virtually nonemissive in dilute solutions (≤0.1 mg mL−1), but highly luminescent upon concentration or aggregation, showing unique concentration‐enhanced emission and aggregation‐induced emission (AIE) characteristics. Notably, apart from well‐documented UV luminescence, bright blue emission is clearly observed. Furthermore, persistent room‐temperature phosphorescence (p‐RTP) is achieved even in the amorphous solids under ambient conditions. This visible emission can be rationalized by the clustering‐triggered emission (CTE) mechanism. These findings not only provide an in‐depth understanding of the emissive properties of proteins, but also hold strong implications for further elucidating the basis of tissue autofluorescence.

Intrinsic emission and persistent room temperature phosphorescence from amorphous nonaromatic polymers are observed, which can be well rationalized by the CTE mechanism.

Nonaromatic luminophores without remarkable conjugates have aroused great attention. Their emission mechanism, however, remains an open question. Meanwhile, previous studies generally focus on aliphatic amine and/or carbonyl-containing systems; those with merely oxygen moieties (i.e., ether, hydroxyl) are scarcely touched. Recently, the clustering-triggered emission (CTE) mechanism is proposed to rationalize the emission of nonconventional luminophores, according to which compounds bearing purely oxygen moieties can also be emissive. To check this conjecture, herein, both nonaromatic compound of xylitol and polymers of PEG and F127 are studied, which are found to be emissive in concentrated solutions and solids. Furthermore, cryogenic-persistent phosphorescence of the compounds and even persistent room temperature phosphorescence of xylitol crystals are observed. Additionally, their potential application as Fe sensors is demonstrated. These results not only verify the rationality of the CTE mechanism but also suggest the possibility to discover and design new luminophores according to it.

Nonaromatic, cross‐conjugated, and highly twisted luminogens consisting of acylated succinimides demonstrate aggregation‐induced emission characteristics along with tunable multicolor photoluminescence and afterglows in their single crystals. Effective through‐space conjugation among different moieties bearing n/π electrons promote the spin–orbit coupling and intersystem crossing and lead to diverse emissive clusters with concurrently rigidified conformations, thus allowing readily tunable emissions. Derived from it, the proof‐of‐concept application for advanced anti‐counterfeiting is illustrated. These results should spur the rational design of novel nonaromatic AIEgens, and moreover advance understandings of the non‐traditional intrinsic luminescence and the origin of tunable multicolor afterglows.