High-Performance Phototransistor Based on a 2D Polybenzimidazole Polymer

Anupam Prasoon; Preetam Dacha; Heng Zhang; Elif Unsal; Mike Hambsch; Alexander Croy; Shuai Fu; Nguyen Ngan Nguyen; Kejun Liu; Haoyuan Qi; Sein Chung; Minyoung Jeong; Lei Gao; Ute Kaiser; Kilwon Cho; Hai I. Wang; Renhao Dong; Gianaurelio Cuniberti; Mischa Bonn; Stefan C.B. Mannsfeld; Xinliang Feng

doi:10.1002/adma.202505810

High-Performance Phototransistor Based on a 2D Polybenzimidazole Polymer

Anupam Prasoon, Preetam Dacha, Heng Zhang, Elif Unsal, Mike Hambsch, Alexander Croy, Shuai Fu, Nguyen Ngan Nguyen, Kejun Liu, Haoyuan Qi, Sein Chung, Minyoung Jeong, Lei Gao, Ute Kaiser, Kilwon Cho, Hai I. Wang, Renhao Dong, Gianaurelio Cuniberti^*, Mischa Bonn^*, Stefan C.B. Mannsfeld^*Xinliang Feng^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

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.

Original language	English
Article number	2505810
Journal	Advanced Materials
DOIs	https://doi.org/10.1002/adma.202505810
Publication status	E-pub ahead of print - 1 Jun 2025

Bibliographical note

Publisher Copyright:
© 2025 The Author(s). Advanced Materials published by Wiley-VCH GmbH.

Funding

A.P., P.D., H.Z., and E.U. contributed equally to this work. This work was financially supported by ERC Consolidator Grant (T2DCP), ERC Starting Grant (FC2DMOF, 852909), H2020-MSCA-ITN (ULTIMATE, no. 813036), CRC 1415 (Chemistry of Synthetic 2D Materials, no. 417590517), SPP 2244 (2DMP), GRK2861 (No. 491865171), as well as the German Science Council and Center of Advancing Electronics Dresden. The authors acknowledge the Center of Advancing Electronics Dresden, and the Dresden Center for Nanoanalysis at TUD. The authors acknowledge also the Center for Information Services and High Performance Computing (ZIH) at TU Dresden for providing the computational resources. The authors would like to thank Marc Malfois with help in setting up the experiment. The authors acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at PETRA III and the authors would like to thank Chen Shen for assistance in using beamline P08. Beamtime was allocated for proposal I-20230095.

Funders	Funder number
Deutsche Forschungsgemeinschaft
ERC Consolidator grant	852909, 813036, CRC 1415, 417590517, SPP 2244 (2DMP), GRK2861, 491865171
ERC starting grant
German Science Council

Keywords

2D polymers
on-water surface synthesis
photodetectors
photoresponsive 2D polymers
phototransistors

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Cite this

Prasoon, A., Dacha, P., Zhang, H., Unsal, E., Hambsch, M., Croy, A., Fu, S., Ngan Nguyen, N., Liu, K., Qi, H., Chung, S., Jeong, M., Gao, L., Kaiser, U., Cho, K., Wang, H. I., Dong, R., Cuniberti, G., Bonn, M., ... Feng, X. (2025). High-Performance Phototransistor Based on a 2D Polybenzimidazole Polymer. Advanced Materials, Article 2505810. Advance online publication. https://doi.org/10.1002/adma.202505810

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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.",

keywords = "2D polymers, on-water surface synthesis, photodetectors, photoresponsive 2D polymers, phototransistors",

author = "Anupam Prasoon and Preetam Dacha and Heng Zhang and Elif Unsal and Mike Hambsch and Alexander Croy and Shuai Fu and {Ngan Nguyen}, Nguyen and Kejun Liu and Haoyuan Qi and Sein Chung and Minyoung Jeong and Lei Gao and Ute Kaiser and Kilwon Cho and Wang, {Hai I.} and Renhao Dong and Gianaurelio Cuniberti and Mischa Bonn and Mannsfeld, {Stefan C.B.} and Xinliang Feng",

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doi = "10.1002/adma.202505810",

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AU - Prasoon, Anupam

AU - Dacha, Preetam

AU - Zhang, Heng

AU - Unsal, Elif

AU - Hambsch, Mike

AU - Croy, Alexander

AU - Fu, Shuai

AU - Ngan Nguyen, Nguyen

AU - Liu, Kejun

AU - Qi, Haoyuan

AU - Chung, Sein

AU - Jeong, Minyoung

AU - Gao, Lei

AU - Kaiser, Ute

AU - Cho, Kilwon

AU - Wang, Hai I.

AU - Dong, Renhao

AU - Cuniberti, Gianaurelio

AU - Bonn, Mischa

AU - Mannsfeld, Stefan C.B.

AU - Feng, Xinliang

PY - 2025/6/1

Y1 - 2025/6/1

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High-Performance Phototransistor Based on a 2D Polybenzimidazole Polymer

Abstract

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Funding

Keywords

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