Lee Hyeokjung, Han Hyowon, Park Chanho, Oh Jin Woo, Kim Hong Hee, Kim Sohee, Koo Min, Choi Won Kook, Park Cheolmin
Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
Small. 2022 Feb;18(6):e2106035. doi: 10.1002/smll.202106035. Epub 2021 Dec 19.
Transition metal dichalcogenide (TMD) nanosheets exfoliated in the liquid phase are of significant interest owing to their potential for scalable and flexible photoelectronic applications. Although various dispersants such as surfactants, oligomers, and polymers are used to obtain highly exfoliated TMD nanosheets, most of them are electrically insulating and need to be removed; otherwise, the photoelectric properties of the TMD nanosheets degrade. Here, inorganic halide perovskite nanocrystals (NCs) of CsPbX (X = Cl, Br, or I) are presented as non-destructive dispersants capable of dispersing TMD nanosheets in the liquid phase and enhancing the photodetection properties of the nanosheets, thus eliminating the need to remove the dispersant. MoSe nanosheets dispersed in the liquid phase are adsorbed with CsPbCl NCs. The CsPbCl nanocrystals on MoSe efficiently withdraw electrons from the nanosheets, and suppress the dark current of the MoSe nanosheets, leading to flexible near-infrared MoSe photodetectors with a high ON/OFF photocurrent ratio and detectivity. Moreover, lanthanide ion-doped CsPbCl NCs enhance the ON/OFF current ratio to >10 . Meanwhile, the dispersion stability of the MoSe nanosheets exfoliated with the perovskite NCs is sufficiently high.
液相剥离的过渡金属二硫属化物（TMD）纳米片因其在可扩展和柔性光电子应用方面的潜力而备受关注。尽管使用了各种分散剂，如表面活性剂、低聚物和聚合物来获得高度剥离的TMD纳米片，但它们中的大多数都是电绝缘的，需要去除；否则，TMD纳米片的光电性能会下降。在此，提出了CsPbX（X = Cl、Br或I）的无机卤化物钙钛矿纳米晶体（NCs）作为非破坏性分散剂，能够在液相中分散TMD纳米片并增强纳米片的光探测性能，从而无需去除分散剂。分散在液相中的MoSe纳米片被CsPbCl NCs吸附。MoSe上的CsPbCl纳米晶体有效地从纳米片中提取电子，并抑制MoSe纳米片的暗电流，从而得到具有高开关光电流比和探测率的柔性近红外MoSe光电探测器。此外，镧系离子掺杂的CsPbCl NCs将开关电流比提高到>10。同时，用钙钛矿NCs剥离的MoSe纳米片的分散稳定性足够高。
