Flexible transition metal dichalcogenide nanosheets for band-selective photodetection

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 MoSe 2 and MoS 2 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 MoSe 2 and MoS 2 gives rise to blended composite films in which the photodetection properties were controllable. The MoS 2 /MoSe 2 (5:5) film showed broad range photodetection suitable for both visible and near infrared spectra. Transition metal dichalgogenide sheets prepared by liquid phase exfoliation can be limited in terms of scalability. Here, Velusamy et al . use a scalable liquid phase exfoliation process to fabricate micrometre thick composite nanosheets with amine-terminated polymers, which exhibit photo-detective properties.