Yoo Changhyeon, Ko Tae-Jun, Han Sang Sub, Shawkat Mashiyat Sumaiya, Oh Kyu Hwan, Kim Bo Kyoung, Chung Hee-Suk, Jung Yeonwoong
NanoScience Technology Center, University of Central Florida Orlando Florida 32826 USA
Department of Materials Science and Engineering, Seoul National University Seoul 08826 South Korea.
Nanoscale Adv. 2021 Apr 6;3(11):3028-3034. doi: 10.1039/d0na01053g. eCollection 2021 Jun 1.
Two-dimensional (2D) molybdenum disulfide (MoS) layers are suitable for visible-to-near infrared photodetection owing to their tunable optical bandgaps. Also, their superior mechanical deformability enabled by an extremely small thickness and van der Waals (vdW) assembly allows them to be structured into unconventional physical forms, unattainable with any other materials. Herein, we demonstrate a new type of 2D MoS layer-based rollable photodetector that can be mechanically reconfigured while maintaining excellent geometry-invariant photo-responsiveness. Large-area (>a few cm) 2D MoS layers grown by chemical vapor deposition (CVD) were integrated on transparent and flexible substrates composed of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNs) by a direct solution casting method. These composite materials in three-dimensionally rollable forms exhibited a large set of intriguing photo-responsiveness, well preserving intrinsic opto-electrical characteristics of the integrated 2D MoS layers; , light intensity-dependent photocurrents insensitive to illumination angles as well as highly tunable photocurrents varying with the rolling number of 2D MoS layers, which were impossible to achieve with conventional photodetectors. This study provides a new design principle for converting 2D materials to three-dimensional (3D) objects of tailored functionalities and structures, significantly broadening their potential and versatility in futuristic devices.
二维（2D）二硫化钼（MoS）层由于其可调节的光学带隙而适用于可见光到近红外光探测。此外，其极小的厚度和范德华（vdW）组装赋予的卓越机械可变形性，使其能够被构造成其他任何材料都无法实现的非常规物理形式。在此，我们展示了一种新型的基于二维MoS层的可卷曲光电探测器，该探测器在保持优异的几何形状不变光响应性的同时可进行机械重构。通过化学气相沉积（CVD）生长的大面积（>几平方厘米）二维MoS层，通过直接溶液浇铸法集成在由2,2,6,6 - 四甲基哌啶 - 1 - 氧基（TEMPO）氧化的纤维素纳米纤维（TOCNs）组成的透明柔性基板上。这些三维可卷曲形式的复合材料展现出一系列引人入胜的光响应性，很好地保留了集成二维MoS层的固有光电特性；即，对光照角度不敏感的光强依赖性光电流以及随二维MoS层卷曲次数变化的高度可调光电流，这是传统光电探测器无法实现的。本研究为将二维材料转变为具有定制功能和结构的三维（3D）物体提供了一种新的设计原理，显著拓宽了它们在未来器件中的潜力和多功能性。
