Halogenated Tetraazapentacenes with Electron Mobility as High as 27.8 cm2 V−1 s−1 in Solution‐Processed n‐Channel Organic Thin‐Film Transistors |
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Authors: | Ming Chu Jian‐Xun Fan Shuaijun Yang Dan Liu Chun Fai Ng Huanli Dong Ai‐Min Ren Qian Miao |
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Affiliation: | 1. Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China;2. Institute of Theoretical Chemistry, Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun, China;3. College of Chemistry and Life Science, Weinan Normal University, Weinan, China;4. Institute of Chemistry, Chinese Academy of Sciences, Beijing, China |
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Abstract: | Molecular engineering of tetraazapentacene with different numbers of fluorine and chlorine substituents fine‐tunes the frontier molecular orbitals, molecular vibrations, and π–π stacking for n‐type organic semiconductors. Among the six halogenated tetraazapentacenes studied herein, the tetrachloro derivative (4Cl‐TAP) in solution‐processed thin‐film transistors exhibits electron mobility of 14.9 ± 4.9 cm2 V?1 s?1 with a maximum value of 27.8 cm2 V?1 s?1, which sets a new record for n‐channel organic field‐effect transistors. Computational studies on the basis of crystal structures shed light on the structure–property relationships for organic semiconductors. First, chlorine substituents slightly decrease the reorganization energy of the tetraazapentacene whereas fluorine substituents increase the reorganization energy as a result of fine‐tuning molecular vibrations. Second, the electron transfer integral is very sensitive to subtle changes in the 2D π‐stacking with brickwork arrangement. The unprecedentedly high electron mobility of 4Cl‐TAP is attributed to the reduced reorganization energy and enhanced electron transfer integral as a result of modification of tetraazapentacene with four chlorine substituents. |
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Keywords: | charge transport electron mobility organic field‐effect transistors organic semiconductors |
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