Journal Article

PUBDB-2025-01777

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png High‐Performance Phototransistor Based on a 2D Polybenzimidazole Polymer

Prasoon, A. ; Dacha, P. ; Zhang, H. ; Unsal, E. ; Hambsch, M.Extern* ; Croy, A. ; Fu, S. ; Ngan Nguyen, N. ; Liu, K.Extern* ; Qi, H.Extern* ; Chung, S. ; Jeong, M. ; Gao, L. ; Kaiser, U. ; Cho, K. ; Wang, H. I. ; Dong, R. ; Cuniberti, G. (Corresponding author) ; Bonn, M. (Corresponding author) ; Mannsfeld, S. (Corresponding author)Extern* ; Feng, X. (Corresponding author)Extern*

2025
Wiley-VCH Weinheim

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Please use a persistent id in citations: doi:10.1002/adma.202505810  doi:10.3204/PUBDB-2025-01777

Abstract: Photodetectors are fundamental components of modern optoelectronics, enabling the conversion of light into electrical signals. The development of high-performance phototransistors necessitates materials with both high charge carrier mobility and robust photoresponse. However, achieving both in a single material poses challenges due to inherent trade-offs. Herein, this study introduces a polybenzimidazole-(1,3-diazole)-based 2D polymer (2DPBI), synthesized as few-layer, crystalline films covering ≈28 cm2 on the water surface at room temperature, with large crystalline domain sizes ranging from 110 to 140 µm2. The 2DPBI incorporates a π-conjugated photoresponsive porphyrin motif through a 1,3-diazole linkage, exhibiting enhanced π-electron delocalization, a narrow direct band gap of ≈1.18 eV, a small reduced electron–hole effective mass (m* = 0.171 m0), and a very high resonant absorption coefficient of up to 106 cm−1. Terahertz spectroscopy reveals excellent short-range charge carrier mobility of ≈240 cm2 V−1 s−1. Temperature-dependent photoconductivity measurements and theoretical calculations confirm a band-like charge transport mechanism. Leveraging these features, 2DPBI-based phototransistors demonstrate an on/off ratio exceeding 108, photosensitivity of 1.08 × 107, response time of 1.1 ms, and detectivity of 2.0 × 1013 Jones, surpassing previously reported standalone few-layer 2D materials and are on par with silicon photodetectors. The unique characteristics of 2DPBI make it a promising foundation for future optoelectronic devices.

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Contributing Institute(s):

1. FS DOOR-User (FS DOOR-User)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. FS-Proposal: I-20230095 (I-20230095) (I-20230095)
3. FC2DMOF - Development of Functional Conjugated Two-Dimensional Metal-Organic Frameworks (852909) (852909)
4. ULTIMATE - Bottom-Up generation of atomicalLy precise syntheTIc 2D MATerials for high performance in energy and Electronic applications – A multi-site innovative training action (813036) (813036)
5. GRK 2861 - GRK 2861: Planare Kohlenstoffgitter (491865171) (491865171)

Experiment(s):

1. PETRA Beamline P08 (PETRA III)

Appears in the scientific report 2025

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Essential Science Indicators ; IF >= 25 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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