Department of Materials Science and Engineering , Yonsei University 50 Yonsei-ro, Seodaemun-gu , Seoul , 03722 , Republic of Korea.
ACS Appl Mater Interfaces. 2018 Oct 10;10(40):34543-34552. doi: 10.1021/acsami.8b07279. Epub 2018 Sep 25.
Two-dimensional (2D) nanosheets of transition metal dichalcogenides (TMDs) are of significant interest for potential photoelectronic applications. However, the fabrication of solution-processed arrays of mechanically flexible thin TMD films-based vertical type p-n junction photodetectors over a large area is a great challenge. Our method is based on controlled solvent evaporation of MoSe suspension spread on water surface. Single or few-layered MoSe nanosheets modified with the dispersant amine-terminated poly(styrene) (PS-NH) were homogeneously deposited and stacked on water upon solvent evaporation, giving rise to uniform MoSe/PS-NH composite films that can be readily transferred onto other substrates. A p-n junction vertical diode of Al/p-type Si/p-type poly(9,9-di- n-octylfluorenyl-2,7-diyl)/n-type MoSe composite/Au stacked from bottom to top exhibited characteristic rectifying current behavior upon voltage sweep with a rectification ratio of 10. Subsequent illumination of near-infrared light on the device resulted in a substantially enhanced dark current of approximately 10 times greater than that of the nonexposed device. The photodetection performance, that is, switching time, responsivity, and detectivity, were 100.0 ms, 2.5 AW, and 2.34 × 10, respectively. Furthermore, the performance of mechanically flexible photodetectors devices was comparable with that of the devices fabricated on the hard Si substrate even after 1000 bending cycles at a bending diameter of 7.2 mm.
二维（2D）过渡金属二卤化物（TMD）纳米片在潜在光电应用中具有重要意义。然而，在大面积上制造基于机械柔性薄 TMD 薄膜的垂直型 p-n 结光电探测器的溶液处理阵列仍然是一个巨大的挑战。我们的方法基于在水面上展开的 MoSe 悬浮液的受控溶剂蒸发。用分散剂胺封端的聚苯乙烯（PS-NH）修饰的单层或少数层 MoSe 纳米片在溶剂蒸发时均匀地沉积和堆叠在水面上，形成均匀的 MoSe/PS-NH 复合膜，可轻易转移到其他基底上。从底部到顶部堆叠的 Al/p 型 Si/p 型聚（9,9-二正辛基芴-2,7-二基）/n 型 MoSe 复合/Au 的 p-n 结垂直二极管在电压扫描时表现出特征整流电流行为，整流比为 10。随后在器件上照射近红外光，导致暗电流大大增强，约为未暴露器件的 10 倍。光电探测性能，即开关时间、响应率和探测率，分别为 100.0 ms、2.5 AW 和 2.34×10，此外，即使在弯曲直径为 7.2mm 的情况下经过 1000 次弯曲循环后，机械柔性光电探测器的性能仍可与在硬 Si 基底上制造的器件相媲美。
