Rapid Photochemical Synthesis of Sea‐Urchin‐Shaped Hierarchical Porous COF‐5 and Its Lithography‐Free Patterned Growth. (4th July 2017)

• Record Type: Journal Article
• Authors: Kim, Soyoung; Park, Chibeom; Lee, Minkyung; Song, Intek; Kim, Jungah; Lee, Minhui; Jung, Jaehoon; Kim, Yousoo; Lim, Hyunseob; Choi, Hee Cheul
• Is Part Of: Advanced functional materials. Volume 27:Number 32(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-07-04
• Subjects: covalent organic frameworks -- hierarchical morphology -- patterned growth -- photochemical synthesis -- porous materials; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201700925
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : Despite potential advantages of covalent organic frameworks (COFs) in wide area applications, several limitations in conventional solvothermal synthesis, such as long reaction time and high reaction temperature, reduce reaction efficiency and prohibit technical processes for practical applications. Therefore, the development of a novel synthesis method that provides better reaction efficiency and spatial controllability has become a critical challenge. Herein, a photochemical synthesis of C9 H4 BO2 (COF‐5) is demonstrated for the first time, by which "sea urchin‐shaped" COF‐5 (UV‐COF‐5) with uniform size is synthesized with a highly enhanced growth rate, ≈48 times faster than that of the solvothermal method for 75% yield. In addition, an enlarged surface area is measured from UV‐COF‐5, which originates from its hierarchical morphology. The selectively increased growth rate of UV‐COF‐5 in the [001] direction observed by microscopic analysis results in the local 1D morphology of the hierarchical structure. Density functional theory calculations determine that the enhanced growth rate along the [001] direction can be understood by the characteristic of the interlayer orbital coupling at the frontier energy region. In addition, this study successfully demonstrates the preparation of COF‐5 patterns without any complicated postsynthesis lithography process, but simply by utilizing optical masks during the photochemical method. Abstract : The synthesis of covalent organic framework‐5 (COF‐5) using a fast photochemical method that allows patterning, is reported for the first time. This novel method yields COF‐5 of hierarchical, homogeneous sea‐urchin‐shaped morphology which has a fast growth rate along out‐of‐plane direction. Also, direct patterned growth of COF‐5 is achieved using reusable optical masks, thereby exploiting using the technical benefit of photochemical synthesis over complicated lithographic processes.