Flexible transition metal dichalcogenide nanosheets for band-selective photodetection

Abstract

The photocurrent conversions of transition metal dichalcogenide nanosheets are unprecedentedly impressive, making them great candidates for visible range photodetectors. Here we demonstrate a method for fabricating micron-thick, flexible films consisting of a variety of highly separated transition metal dichalcogenide nanosheets for excellent band-selective photodetection. Our method is based on the non-destructive modification of transition metal dichalcogenide sheets with amine-terminated polymers. The universal interaction between amine and transition metal resulted in scalable, stable and high concentration dispersions of a single to a few layers of numerous transition metal dichalcogenides. Our MoSe2 and MoS2 composites are highly photoconductive even at bending radii as low as 200 μm on illumination of near infrared and visible light, respectively. More interestingly, simple solution mixing of MoSe2 and MoS2 gives rise to blended composite films in which the photodetection properties were controllable. The MoS2/MoSe2 (5:5) film showed broad range photodetection suitable for both visible and near infrared spectra.

A highly sensitive, highly transparent, gel-gated MoS2 phototransistor on biodegradable nanopaper

“…We have carried out systematic 28 studies on its electrical and optoelectronic properties. The MoS 2 phototransistor exhibited 29 excellent photo responsivity of ~1.5 kA/W, about two times higher compared to typical back- 30 gated devices reported in previous studies. The device is highly transparent at the same time with 31 an average optical transmittance of 82%.…”

“…19 These ecofriendly transistors can help conserve non- Phototransistor is essentially a light-sensitive field effect transistor (FET) that transduces 61 incoming photo energy to electrical current. [27][28][29] Its special band structure, mechanical flexibility and ease of processing make MoS 2 an ideal candidate material for optoelectronics applications. [20][21][22] Among them, MoS 2 has received 63 particular interest due to its unique electrical and optical properties.…”

Assembly and Electronic Applications of Colloidal Nanomaterials

“…This approach has proven to be effective for dispersing carbon nanotubes, [114,115] graphene oxide, [116,117] pristine graphene, [118][119][120] hexagonal boron nitride (h-BN), [121][122][123] 2D transition-metal dichalcogenide (TMD) nanosheets, [7,124,125] black phosphorous, [126,127] and other 2D nanomaterials. [119,125,126,[131][132][133][134] Sources of energy for exfoliation include sonication, [134] ball milling, [123] shear-mixing, [8] and high-pressure homogenization. [119,125,126,[131][132][133][134] Sources of energy for exfoliation include sonication, [134] ball milling, [123] shear-mixing, [8] and high-pressure homogenization.…”

Flexible Nonvolatile Transistor Memory with Solution‐Processed Transition Metal Dichalcogenides

“…2D nanosheets of transition metal dichalcogenides (TMDs) such as MoS 2 , WS 2 , and MoSe 2 have been of great attraction due to their intriguing properties associated with their unique 2D confined chemical structures . Numerous proof‐of‐concept photoelectric devices with TMDs have been developed, including FETs, photodetectors, logic circuits, and nonvolatile memories . In particular, in most of the transistor memories, TMDs have been employed as semiconducting channel layers, and only a few works addressed the charge‐trapping properties of TMDs in the memories …”

“…Considering that conventional chemical vapor deposition (CVD) processes are barely applicable to flexible plastic substrates, a thin TMD film should be prepared by a solution‐based technique, which involves not only efficient exfoliation of the sheets of 2D TMDs from stacked bulk samples, but also prevention of reaggregation of the sheets upon film formation, without harming a flexible substrate. Our TMD exfoliation and dispersion method based on amine‐terminated polymers provides a very efficient way to fabricate TMD composite films, in which the concentration of TMDs dispersed in polymer matrix is readily controlled …”