Self-driven photodetection based on impedance matching effect between a triboelectric nanogenerator and a MoS2 nanosheets photodetector

Constructing electronic systems without an external power source is urgently required toward self-powered photodetection. In this work, we proposed a self-driven photodetection system with a MoS2 nanosheets photodetector as light intensity sensor, a vertical contact-separate mode triboelectric nanogenerator (CS-TENG) as power source, and several LEDs as alarm. The MoS2 based planar photodetector was fabricated by conventional photolithography technique and lift-off process. It is highly sensitive for visible light illumination with high current on-off ratio and excellent reproducibility characteristics under light on-off switching. When conjuncting these functional devices, the induced output voltage of the CS-TENG is tuned by the load resistance of the photodetector, which is responded to the light intensity. The mechanism can be ascribed to the impedance matching effect between specific output characteristics of TENG and working status of photodetector. By adding a Zener diode acts as a voltage regulator, the self-driven renders the voltage and current varying from 1.58 to 20.60 V and 0.06–4.78 μA in a range of light intensity from 0 to 3.19 W/m2, respectively. Finally, it is demonstrated that the output of CS-TENG varies with the variable working states of the MoS2 photodetector and then accurately reflects on the lighted number of LEDs.