Enhancing Photodetection Ability of MoS₂ Nanoscrolls via Interface Engineering

Abstract

Van der Waals semiconductors have been really confirmed in twodimensional (2D) layered systems beyond the traditional limits of lattice-matching requirements. The extension of this concept to the 1D atomic level may generate intriguing physical functionalities due to its non-covalent bonding surface. However, whether the curvature of the lattice in such rolled-up structures affects their optoelectronic features or the performance of devices established on them remains an open question. Here, MoS 2 -based nanoscrolls were obtained by virtue of an alkaline solution-assisted method and the 0D/1D (BaTiO 3 /MoS 2 ) strategy to tune their optoelectronic properties and improve the light sensing performance was explored. The capillary force generated by a drop of NaHCO 3 solution could drive the delamination of nanosheets from the underlying substrate and a spontaneous rolling-up process. The package of BaTiO 3 particles in MoS 2 nanoscrolls has been evident by TEM image, and the optical characterizations were mirrored via micro-Raman spectroscopy and photoluminescence. These bare MoS 2 nanoscrolls reveal a reduced photoresponse compared to the plane structures due to the curvature of the lattice. However, such BaTiO 3 /MoS 2 nanoscrolls exhibit a significantly improved photodetection (R hybrid = 73.9 A/ W vs R only = 1.1 A/W and R 2D = 1.5 A/W at 470 nm, 0.58 mW•cm −2 ), potentially due to the carrier extraction/injection occurring between BaTiO 3 and MoS 2 . This study thereby provides an insight into 1D van der Waals material community and demonstrates a general approach to fabricate high-performance 1D van der Waals optoelectronic devices.

Liquid-crystalline circularly polarised TADF emitters for high-efficiency, solution-processable organic light-emitting diodes

“…Recently, liquid crystals have aroused interest in the generation of circularly polarised light due to their excellent selforganisation properties [34][35][36] and some groups have reported a high g lum value by doping a chiral emitter into an achiral liquid crystal, proving that the liquid crystal can amplify the g lum value. 35,37 Very recently, Li et al achieved a strong CPL signal of |g lum | = 0.47 using the orientational order parameter of achiral dyes in cholesteric liquid crystal media. 38 Our previous work also demonstrated that integrating liquid crystallinity and phosphorescence can lead to impressive values of g lum of 10 À2 in an OLED device.…”

Monitoring Soft Shape Surface Deformation via Optical Images for the Distinction of Contact State

“…Therefore, accurately identifying the elastomer deformation is a key issue for understanding the contact state in soft touch. [18][19][20][21][22][23][24][25][26][27] At present, methods utilizing feature points are used to characterize the deformation of elastomers, such as robots' hand grasp tasks based on elastomer design [28] and slip detection. [29] In this method, the elastomer surface is divided into discrete regions by setting the feature points array on the elastomer.…”

Spontaneous formation of MoS2 nanoscrolls from flat monolayers with sulfur vacancies: a molecular dynamics investigation

“…Taking MoS 2 as an example, the preparation methods can be classified into two categories by involving additional medium or not. The commonly used media included organic solvents (ethanol, 14–17 IPA 18 ), alkaline solutions (NaHNO 3 , 19 NH 3 ·H 2 O, 20 KOH 21 ) and deionized water. 22 Cui et al 17 successfully achieved the in situ conversion of monolayer MoS 2 nanosheets grown via chemical vapor deposition into high-quality nanoscrolls using a single droplet of ethanol solution.…”