Details

Autor(en) / Beteiligte

• Yang, Meijia
• Mo, Chunshao
• Fang, Long
• Li, Jing
• Yuan, Zhongke
• Chen, Zhiyong
• Jiang, Qiongchao
• Chen, Xudong
• Yu, Dingshan

Titel

Multibranched Octupolar Module Embedded Covalent Organic Frameworks Enable Efficient Two‐Photon Fluorescence

Ist Teil von

• Advanced functional materials, 2020-08, Vol.30 (34), p.n/a

Ort / Verlag

Hoboken: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Covalent organic frameworks (COFs) have emerged as potential light emitting polymers for optoelectronic and optical devices, but their nonlinear optical properties, particularly two‐photon absorption and fluorescence (TPA/TPF), have seldom been explored. Herein, to construct octupolar three‐branched modules (e.g., acceptor 3‐(donor‐core), triphenylbenzene core) within a 2D cyano‐sp2c‐conjugated framework is proposed that results in two‐photon luminescent COFs, combining a large TPA cross section and high quantum yield (QY). Such octupolar module‐embedded sp2c‐conjugated COFs emit not only intense one‐photon fluorescence with QY of 27.2% in the solid state and 38.1% in tetrahydrofuran—superior to almost all reported COFs, but also efficient two‐photon fluorescence with large TPA cross section of 1225 GM—remarkably surpassing the corresponding cyano‐sp2c‐linked model compounds (104 GM). The finding highlights the synergy between sp2c‐conjugated framework and octupolar modules that leads to markedly improved TPA response owing to extended conjugated length, enhanced planarity and multidimensional intramolecular interaction. In view of the versatility of the branched chromophore, the proposed design idea is expected to be used to exploit more two‐photon active COF materials for a range of applications. Multiple uses of the COF in information encryption and warm white light‐emitting diodes are also exemplified. Octupolar three‐branched modules embedded in a 2D cyano‐sp2c‐conjugated framework enable two‐photon luminescent covalent organic frameworks (COFs) combining a large two‐photon absorption cross section of 1225 GM and intense one‐photon fluorescence with a quantum yield of 27.2% in solid state and 38.1% in tetrahydrofuran—superior to almost all reported COFs, which can be used in information encryption and warm white light‐emitting diodes.