High photosensitivity with enhanced photoelectrical contribution in hybrid nanocomposite flexible UV photodetector

• Synthesis of PPani–TiO2 nanocomposite films by a single step plasma based process.
• Development of a flexible hybrid UV photodetector.
• High photosensitivity of ∼519 is obtained for the hybrid photodetector.
• Hybrid photodetector showed high photoconductive gain and high responsivity.
• The photodetector exhibits excellent flexibility and good folding strength.

To devise a reliable strategy to develop an ultraviolet (UV) sensitive hybrid photodetector, plasma process is utilized as a single step method for production of large area nanocomposite films based on plasma polymerized aniline–titanium dioxide (PPani–TiO2). The synthesis of PPani–TiO2 nanocomposite films are made using reactive magnetron sputtering in combination with plasma polymerization. The deposited PPani–TiO2 nanocomposite films are characterized and discussed in terms of structural, optical and electrochemical properties. A hybrid flexible nanostructured UV photodetector is constructed from PPani–TiO2 nanocomposite and its optoelectronic properties are evaluated which exhibits a greatly enhanced photosensitivity resulting in high photoconductive gain (G = 4.56 × 104) and high responsivity (R = 9.36 × 103 AW−1) under UV illumination of 254 nm. The flexible devices are successfully operated under bending up to 170° (bending radius, R = 8 mm) and showed a good folding strength and stability. The proposed plasma based method provides a green technology where the self-assembly of molecules, that is, the spontaneous association of atomic or molecular building blocks under plasma environment, emerge as a successful strategy to form well-defined structural and morphological units of nanometer dimensions.

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