Encapsulation of AIEgens within Metal–Organic Framework toward High‐Performance White Light‐Emitting Diodes

Abstract

White light‐emitting diodes (WLEDs) have a wide range of applications in display and illumination, however, it is still challenging to achieve efficient solid‐state white light‐emitting (WLE) materials due to the conventional quenching effect. Herein, a strategy of encapsulating aggregation‐induced emission luminogens (AIEgens) into the pores of metal–organic framework (MOF) to achieve high‐performance WLED is proposed. Two cationic dyes, 2,3,4,5‐tetrakis(4‐methoxyphenyl)oxazol‐3‐ium (MOTPO) and 1‐methyl‐4‐(4‐(1,2,2‐triphenylvinyl)phenyl)pyridin‐1‐ium (TPEPy) with bright blue and yellowish green emissions, respectively, are synthesized and successfully incorporated into the pore of anionic MOF ZJU‐28. The synergy of AIE characteristics and confinement effect within hybrid material result in an enhanced emission signal in comparison to each of the individual components. The single‐phase WLE material with Commission International de L'Eclairage coordinates of (0.35, 0.34) and the quantum efficiency of 64.9% is realized by optimizing the ratio between the two guests, which is almost the best among the reported WLE MOF composites to date. The resulting WLED demonstrates the maximum external quantum efficiency of 12.67% accompanied by the excellent color‐rendering index and correlated color temperature of 86 and 4076 K, respectively. Moreover, the WLE flexible film is also achieved. This work will provide new insights and strategies for the design of efficient WLEDs in the future.

Introduction of Multicomponent Dyes into 2D MOFs: A Strategy to Fabricate White Light-Emitting MOF Composite Nanosheets

“…The emission peaks of the RB/PMMA mixture (0.1 wt % RB) and RB@HSB-W5-Ns (0.1 wt % RB) all exhibited obvious bathochromic shifts. These phenomena may result from that the dye molecules are randomly distributed in the ethanol solution or PMMA; however, the dye molecules are confined between layers in the HSB-W5-Ns due to the confinement effect . On the other hand, a certain degree of aggregation of dye molecules in PMMA and the interlayer of HSB-W5 leads to the bathochromic shifts and a decrease in the quantum yield (Table S5).…”

“…These phenomena may result from that the dye molecules are randomly distributed in the ethanol solution or PMMA; however, the dye molecules are confined between layers in the HSB-W5-Ns due to the confinement effect. 69 On the other hand, a certain degree of aggregation of dye molecules in PMMA and the interlayer of HSB-W5 leads to the bathochromic shifts and a decrease in the quantum yield (Table S5). 70 We further examined the fluorescence lifetimes of the RB/C 2 H 5 OH solution, RB/PMMA mixture, and RB@HSB-W5-Ns, as shown in Table S5 and Figure S21; the lifetime of RB@HSB-W5-Ns is lower than that of the RB/PMMA mixture, which demonstrated that there is obvious energy transfer between the dye molecules and MOF host.…”

Metal–organic frameworks with aggregation‐induced emission

“…and co-workers synthesized two cationic dyes, namely 2,3,4,5tetrakis(4-methoxyphenyl)oxazol-3-ium (MOTPO) and 1-methyl-4-(4-(1,2,2-triphenylvinyl)phenyl)pyridin-1-ium (TPEPy), that exhibit bright blue and yellowish green emissions, respectively. [86] These dyes were then integrated into the pore of the anionic framework ZJU-28. The combination of AIE characteristics and confinement effects in the hybrid material leads to a stronger emission signal than that of the individual components.…”

Encapsulation engineering of porous crystalline frameworks for delayed luminescence and circularly polarized luminescence

“…If the emission of MOFs exceeds the range of blue light, it is difficult to achieve white light with the introduction of guests. 176,177 In the case of phosphorescence, the energy transfer and matching for the regulation of phosphorescence in host-guest systems are more complicated. Specifically, the singlet states and triplet states of the host structure and guest emitters need to be coordinated and their energy levels must facilitate ISC to improve the phosphorescence efficiency.…”