Application of a Bio-Nanocomposite Tissue as an NIR Optical Receiver and a Temperature Sensor

The application of a type of bio-nano tissue, consisting of tobacco cells and multiwalled carbon nanotubes, as a sensitive near-infrared region (NIR) bolometer operating at room temperature was investigated. An electrical resistor-type sensor was fabricated by the evaporation of lateral gold contacts. A very low dark conductivity was achieved by a high-voltage treatment of a strongly conducting nanotube network. Although before the treatment the electrical transport was dominated by the percolative transport in the nanotube network, after the voltage stress the electronic transport in the low-conductivity tissue was controlled only by the intrinsic electrical properties of the biological matrix. In this latter case, the conductivity was extremely temperature and humidity dependent. However, on operating the sensor tissue in a small temperature window around room temperature, the change in humidity could be neglected. Under these conditions, the multifunctional device functioned as a very high sensitivity temperature sensor with a temperature coefficient of resistance of more than -20%/K. Sensitive bolometer operation with a very good signal-to-noise ratio was demonstrated by irradiation of the tissue with low-power LEDs in the near-infrared range between 780 and 1720 nm.