Observation of Ultrahigh Photoconductivity in DNA‐MoS₂ Nano‐Biocomposite

Abstract 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 plays another major obstacle. Here ultrahigh photoconductivity is observed in deoxyribonucleic acid‐molybdenum disulfide (DNA‐MoS₂) nano‐biocomposite film by incorporating a high‐concentration, well‐percolated, and uniform MoS₂ network in the ss‐DNA matrix. This is achieved by utilizing DNA‐MoS₂ hydrogel formation, which results 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) is observed, five orders of magnitude higher than conventional biomaterials (≈10¹) reported so far. The incorporation of the Wely semimetal (Bismuth) as an electrical contact exhibits ultrahigh photoresponsivity (2.6 × 10⁵ A W⁻¹). Such high photoconductivity in DNA‐MoS₂ nano‐biocomposite could bridge the gap between biology, electronics, and optics for innovative biomedicine, bioengineering, and neuroscience applications.