Achieving Amorphous Ultralong Room Temperature Phosphorescence by Coassembling Planar Small Organic Molecules with Polyvinyl Alcohol

Abstract

Development of novel strategies for achieving amorphous ultralong organic phosphorescence (UOP) at room temperature is highly desired. Herein, a simple approach is reported by coassembling small organic molecules with polyvinyl alcohol (PVA) to afford amorphous UOP. These small organic molecules with planar conformation present quenched triplet state emission in an excessive stacking solid state. When coassembling these molecules with PVA, their planar structures are well confined in coassembly films. Such a confined environment leads to restricted molecular rotation and vibration, permitting these molecules to show stable triplet state and generate UOP. In control studies, corresponding structurally distorted molecules are also coassembled with PVA. However, they exhibit very weak or quenched UOP, since distorted structures with molecular rotation and vibration could easily dissipate the excitation energy in dilute film state. By employing this polymer confinement strategy, multicomponent luminescence dyes are further coassembled with PVA for multicolor luminescence displays, providing multicolor, uniform, and flexible luminescence films. This work demonstrates a general strategy of employing small organic molecules to coassemble with PVA to obtain amorphous UOP, which greatly expands the scope of organic molecules for developing simple but useful UOP films.

A facile way to obtain near-infrared room-temperature phosphorescent soft materials based on Bodipy dyes

“…[19][20][21][22][23][24][25][26] Various phosphors with different conjugated structures have been utilized to obtain RTP emission of different colours, most of which are excited by UV light and exhibit RTP emission in the visible region. [27][28][29][30][31] Materials with absorption in the visible region and emission in the NIR region are promising candidates in a wide range of elds, such as medical and therapeutic applications, due to their high tissue penetration and low autouorescence. [32][33][34][35] Up till now, materials with NIR RTP emission have been essentially limited to metal complexes like Pt and Ir, which suffer from complicated synthesis, high cost and biotoxicity.…”

Quinoline-containing diarylethenes: bridging between turn-on fluorescence, RGB switching and room temperature phosphorescence

“…It is therefore important to target new materials that display RTP in the amorphous state. Host-guest interactions, molecular assembly and polymerization have been utilized to achieve this goal, [31][32][33][34][35][36][37][38] however small molecules that show phosphorescence in the amorphous state have rarely been reported in the literature and most are highly halogenated. 8,[39][40][41][42] To tackle these challenges, we decided to employ DAEs as building blocks for RTP materials.…”

All‐Organic, Temporally Pure White Afterglow in Amorphous Films Using Complementary Blue and Greenish‐Yellow Ultralong Room Temperature Phosphors

“…It has been well established by Zhao and co-workers, that supramolecular cross-linking between the PVA chains and functionalized phosphors using secondary noncovalent interactions would suppress the molecular motions to minimize the nonradiative dissipation of triplets to facilitate ambient triplet harvesting. [43][44][45][46] We have recently reported greenish-yellow afterglow phosphorescence from coronene tetracarboxylate (CS) anchored to PVA chains with high phosphorescence quantum efficiency (≈25%) and long-lifetime (≈2.5 s) in air and are used as the greenish-yellow phosphor in the present study. [24] Further design of ambient white afterglow would require an efficient blue afterglow phosphor, which is very rarely reported in literature.…”