Observation of Ultrahigh Photoconductivity in DNA-MoS 2 Nano-Biocomposite.

A nano-biocomposite film with ultrahigh photoconductivity remains elusive and critical for bio-optoelectronic applications. A uniform, well-connected, high-concentration nanomaterial network in the biological matrix remains challenging to achieve high photoconductivity. Wafer-scale continuous nano-biocomposite film without surface deformations and cracks play another major obstacle. Here we observed ultrahigh photoconductivity in DNA-MoS2 nano-biocomposite film by incorporating a high-concentration, well-percolated, and uniform MoS2 network in the ss-DNA matrix. This was achieved by utilizing DNA-MoS2 hydrogel formation, which resulted in crack-free, wafer-scale DNA-MoS2 nano-biocomposite films. Ultra-high photocurrent (5.5 mA at 1 V) with a record-high on/off ratio (1.3×106) was observed, five orders of magnitude higher than conventional biomaterials (∼101) reported so far. The incorporation of the Wely semimetal (Bismuth) as an electrical contact exhibited ultrahigh photoresponsivity (2.6×105 A/W). Such high photoconductivity in DNA-MoS2 nano-biocomposite could bridge the gap between biology, electronics, and optics for innovative biomedicine, bioengineering, and neuroscience applications. This article is protected by copyright. All rights reserved.