Prasoon Anupam, Dacha Preetam, Zhang Heng, Unsal Elif, Hambsch Mike, Croy Alexander, Fu Shuai, Ngan Nguyen Nguyen, Liu Kejun, Qi Haoyuan, Chung Sein, Jeong Minyoung, Gao Lei, Kaiser Ute, Cho Kilwon, Wang Hai I, Dong Renhao, Cuniberti Gianaurelio, Bonn Mischa, Mannsfeld Stefan C B, Feng Xinliang
Center for Advancing Electronics Dresden (cfaed) and Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, 01062, Dresden, Germany.
Max Planck Institute for Microstructure Physics, D-06120, Halle, Germany.
Adv Mater. 2025 Aug;37(33):e2505810. doi: 10.1002/adma.202505810. Epub 2025 Jun 1.
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 cm on the water surface at room temperature, with large crystalline domain sizes ranging from 110 to 140 µm. 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 m), and a very high resonant absorption coefficient of up to 10 cm. Terahertz spectroscopy reveals excellent short-range charge carrier mobility of ≈240 cm V s. 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 10, photosensitivity of 1.08 × 10, response time of 1.1 ms, and detectivity of 2.0 × 10 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.
光电探测器是现代光电子学的基本组件，能够将光转换为电信号。高性能光电晶体管的发展需要具有高电荷载流子迁移率和强大光响应的材料。然而，由于固有的权衡，在单一材料中同时实现这两点具有挑战性。在此，本研究介绍了一种基于聚苯并咪唑 -（1,3 - 二唑）的二维聚合物（2DPBI），它在室温下合成的少层结晶薄膜可覆盖水面上约28平方厘米，具有110至140微米的大晶畴尺寸。2DPBI通过1,3 - 二唑键合并入一个π共轭光响应卟啉基序，表现出增强的π电子离域、约1.18电子伏特的窄直接带隙、小的折合电子 - 空穴有效质量（m* = 0.171m）以及高达10厘米的非常高的共振吸收系数。太赫兹光谱揭示了约240平方厘米/伏·秒的出色短程电荷载流子迁移率。温度相关的光电导率测量和理论计算证实了带状电荷传输机制。利用这些特性，基于2DPBI的光电晶体管展示出超过10的开/关比、1.08×10的光敏度、1.1毫秒的响应时间以及2.0×10琼斯的探测率，超过了先前报道的独立少层二维材料，与硅光电探测器相当。2DPBI的独特特性使其成为未来光电器件的有前途的基础。
