Efficient Room‐Temperature Phosphorescence of a Solid‐State Supramolecule Enhanced by Cucurbit[6]uril

Abstract

Efficient emission of purely organic room-temperature phosphorescence (RTP) is of great significant for potential application in optoelectronics and photobiology. Herein, we report an uncommon phosphorescent effect of organic single molecule enhanced by resulting supramolecular assembly of host-guest complexation. The chromophore bromophenyl-methyl-pyridinium (PY) with different counterions as guests displayvarious phosphorescence quantum yields from 0.4 %t o2 4.1 %. Single crystal X-rayd iffraction results indicate that the chromophore with iodide counterion (PYI) exhibits the highest efficiency maybe due to the halogen-bond interactions.S ignificantly,t he nanosupramolecular assembly of PY chloride complexation with the cucurbit[6]uril gives agreatly enhanced phosphorescent quantum yield up to 81.2 % in ambient. Such great enhancement is because of the strict encapsulation of cucurbit[6]uril, which prevents the nonradiative relaxation and promotes intersystem crossing (ISC). This supramolecular assembly concept with counterions effect provides anovel approach for the improvement of RTP.Organic room-temperature phosphorescent (RTP) has got tremendous attention due to their extensive application in optoelectronics [1] and photobiology, [2] such as organic lightemitting diodes [3] and bioimaging. [4] So far, most of organic RTPm aterials are organometallic complexes.C onsidering their high cost and restriction in resources,t he development of purely organic (metal-free) phosphorescent materials are of great concern.[5] However,p hosphorescence of purely organic molecules are fairly weak owing to their inefficient spin-orbit coupling, [6] hence massive efforts have been devoted to achieving efficient RTPb yd eveloping new methods,s uch as special design of structure, [7] embedding into proper matrix [8] and careful crystallization. [9] Recently, aprinciple of using directed heavy atom effect to facilitate the efficiency of phosphorescence (phosphorescence quantum yield 55 %) has been reported by Kim and co-workers. [10] Moreover,external heavy atom effect is proven to be another effective method in fabricating efficient phosphorescent materials (phosphorescence quantum yield 36 %). [11] On the other hand, supramolecular approach have been used extensively to construct functional materials by complexing or assembly.N oncovalent interactions,s uch as host-guest interaction, [12] hydrogen bonding, [13] p-p stacking [14] can alter the properties of guests greatly.Recently,Huang and co-workers reported asupramolecular strategy to enhance the efficiency (phosphorescence quantum yield 24.3 %) and extend the lifetime of phosphorescence by constructing crystalline framework. [13] Moreover,i ti sw ell known that the complexation between macrocycles (especially for cyclodextrin [15] and cucurbituril [16] )a nd luminous guests have great impact on photoluminescent characters.M ore recently,T ian and coworkers reported adecent quantum yield (16.9 %) of organic RTPinduced by hydrogen bonding of chromophore modified cyclodextrin...

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.…”

Proton‐Activated Amorphous Room‐Temperature Phosphorescence for Humidity Sensing and High‐Level Data Encryption

“…Figure A and 2B present the RTP emission of 1 @ LP and 2 @ LP , which reveal different maximum emission wavelength (526 nm for 1 @ LP and 500 nm for 2 @ LP ). Furthermore, the time‐resolved decay curves fitted by a biexponential function reveal long phosphorescence lifetimes of 1.131 s and 1.050 s, respectively (Figure C, Figure D and Table ), which is one of the most ultralong RTP lifetime for small molecules‐based amorphous RTP materials reported so far . The phosphorescence quantum yields of 1 @ LP and 2 @ LP excited at 365 nm are 2.96% and 1.86%, respectively.…”

Encapsulation of a Porous Organic Cage into the Pores of a Metal–Organic Framework for Enhanced CO2 Separation

“…In summary,wehave confined aporous organic cage into the nanocages of MIL-101 by the incipient-wetness impregnation method, obtaining the host-in-host adsorbent CB6@MIL-101, which showed enhanced performance in selective CO 2 adsorption and separation at low pressures. We believe that the host-in-host concept can be extended to encapsulate ab road range of POCs into porous crystalline materials such as MOFs,e ither by in situ assembly of host MOFs or by post-impregnation methods.T his can lead to advanced porous materials,w hich could combine the merits (such as tailor-made intrinsic pores for molecule capture and separation, [9b,c] enzymatic catalysis, [33] confinement effects [34] ) of porous organic molecules and the tunable,h ighly ordered architectures of functional MOFs. [3]…”