Colour-tunable ultra-long organic phosphorescence of a single-component molecular crystal

Stimuli‐Responsive Circularly Polarized Organic Ultralong Room Temperature Phosphorescence

“…Previous attempts only succeed in two multi‐component host‐guest and ionic cocrystal systems, showing circularly polarized OURTP (CP‐OURTP) with lifetimes of ≈0.67 and 0.86 s and dissymmetry factors ( g lum ) of ≈4.5×10 −4 and 2.0×10 −4 , respectively. Considering the intrinsic difficulties in promoting intersystem crossing and aggregation coupling for OURTP and in realizing efficient charity transfer from chiral groups to luminescent aggregates for CPL simultaneously in a purely organic molecule, it has yet to construct a single‐component CP‐RTP or CP‐OURTP molecular system with a verified g lum in solid state, despite the recent prosperity of RTP and OURTP materials …”

“…[1][2][3][4][5][6] Exponential attention has been paid to the design and fabrication of novel CPL-featured organic optoelectronic materials including fluorescence organic luminophores, [7][8][9] thermally activated delayed fluorescence molecules, [10,11] and metal-organic phosphorescent complexes. [12] Ther ecent development of room temperature phosphorescence (RTP) of purely organic materials,e specially organic ultralong RTP( OURTP) with lifetimes over 100 ms [13][14][15][16][17][18] has significantly shaped the understanding of organic optoelectronics. [19] However, it remains ad aunting challenge to implant CPL in metal-free RTP materials,l et alone in OURTP molecules.…”

“…[20] Previous attempts only succeed in two multi-component host-guest [21] and ionic cocrystal systems, [22] showing circularly polarized OURTP (CP-OURTP) with lifetimes of % 0.67 and 0.86 sand dissymmetry factors (g lum )o f% 4.5 10 À4 and 2.0 10 À4 , respectively.C onsidering the intrinsic difficulties in promoting intersystem crossing and aggregation coupling for OURTP and in realizing efficient charity transfer from chiral groups to luminescent aggregates for CPL simultaneously in ap urely organic molecule,i th as yet to construct as inglecomponent CP-RTP or CP-OURTP molecular system with av erified g lum in solid state,d espite the recent prosperity of RTPa nd OURTP materials. [14,15] To realize the single-component CP-OURTP in purely organic small molecules,weherein propose aone-stone-twobirds strategy through flexible chiral chain engineering by direct bonding ac hiral center to ap hosphor capable of RTP emission for (1) efficient chirality transfer and (2) dynamically self-adaptive aggregation coupling upon photo-activation for OURTP.Specifically,the chiral chain can successfully introduce the chiral character to the aromatic group for CP-RTPa nd effectively manipulate the molecular arrangement and packing mode in aggregated structures for enhancing the solid-state chiral emission. [23] Moreover,t he flexible chain that can be driven by external stimuli will dynamically tune the molecular stacking under photon irradiation for more effective aggregation coupling in solid states, [24] which is beneficial to stabilize the highly active excited triplet excitons for high-performance CP-OURTP.…”

Organic Room Temperature Phosphorescence Materials for Biomedical Applications

“…On the basic of these factors, researchers have proposed various strategies and methods to moldulate phosphorescent performance, such as intruduction of heavy atoms, heteroatoms and aromatic carbony to boost SOC; while suppressing non‐radiation of the triplet excitons by host‐guest doping method crystalization and organic flameworks . Therefore, developing metal‐free organic luminescent materials with highly efficient room temperature phosphorescence has been becoming a hot topic in recent years …”

“…[35][36][37] Therefore, developing metal-free organic luminescent materials with highly efficient room temperature phosphorescence has been becoming a hot topic in recent years. [38][39][40] In the respect of applications, RTP materials show great potential in modern biomedical science owing to its unique property of long emission lifetime. Conventional bioimaging relies on fluorescent signals acquired upon real-time light excitation to delineate biological tissues, wherein autofluorescence from endogenous fluorophores is inevitable.…”