▎ 摘　　要

In this research, flexible, low in cost, simple in design and stable in functionality humidity sensors have been developed. The first category of sensors had 300 nm thick silver (Ag) metal as bottom electrodes with an inter electrode spacing of 16 lm, deposited on top of a flat rubber substrate. A 9-11 lm thick film com-prising of orange dye (20 wt.%), graphene (30 wt.%) and silicone adhesive (50 wt.%), has been deposited on Ag electrodes to define the channel of two terminals resistive sensors. In the second category, a 5-6 lm thick gate layer consisting of graphene (50 wt.%) and silicone adhesive (50 wt.%) has been additionally deposited on top of the channel layer to achieve organic field effect transistor (OFET) based sensors. The impedance variation of the fabricated sensors has been investigated by varying ambient relative humidity (RH) from 33 to 94 % at frequencies 100 Hz, 1 kHz, 10 kHz, 100 kHz and 200 kHz. It has been observed that the output impedance of these sensors decreases with the increase in humidity. The change in impedance at 100 Hz was 2140 times for the resistive design whereas, it was 3716 times for OFET type sensors. It has been demonstrated that both type of sensors offered stable response for temperature range 22-75 degrees C and for a time interval of 240 h. Apart from environmental monitoring, the developed sensors being conformal in nature can comfortably be employed in biomedical applications such as personal health care monitoring systems.