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• Integrated micro temperature and humidity sensors. • Real time temperature compensation for humidity sensors output. • Liquid mechanical exfoliation of MoS2 to achieve 2D flakes and particles suspended in PEO polymer matrix. • Detailed investigation of working principle and sensing mechanism. • Micron level size compatible with integration in MEMS based commercial devices. Percentage relative humidity is dependent on environmental temperature but the fact is ignored in most of research on humidity sensors. Secondly, the physical size of sensors should be small enough to enable integration on a commercial microchip. In this work, an integrated micro temperature plus humidity sensor system is presented that compensates for the effect of surrounding temperature on the output resistance of humidity sensor. The sensors were fabricated using Electrohydrodynamic drop-on-demand (EHD-DOD) printing for the electrodes, and Electrospray deposition (ESD) for active layer fabrication of humidity sensors. Electrode line widths were 10 μm while the combined area of both sensors was ∼2 mm2. Meander type silver patterns were used as resistive temperature sensors and interdigitated transducer (IDT) electrodes were used for humidity sensors. The active layer of humidity sensors was fabricated using a novel composite of Polyethylene Oxide (PEO) and 2D Molybdenum disulfide (MoS 2) flakes to achieve a highly sensitive (85 kΩ/%RH) and almost linear response for a wide detection range (0–80% RH) of relative humidity. A mathematical model relating the outputs of both sensors was developed to compensate for the effects of temperature. The system presents optimal solution for commercialization ready temperature compensated integrated micro temperature and humidity sensors fabricated through all printing techniques. [ABSTRACT FROM AUTHOR]

In this work, a polymeric material poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and a two dimensional material molybdenum disulfide (MoS 2 ) 2D nanoflakes have been employed as the active layers of two separate transducers on a single substrate for the detection of relative humidity. The portion with MoS 2 based active region showed high responsivity towards low humidity levels while PEDOT:PSS based portion responded well to high humidity levels. These two sensing portions were connected in a series combination to fabricate a single humidity sensing device capable to respond to a wide range of relative humidity with very high sensitivity. 2D MoS 2 nanoflakes were obtained by aqueous exfoliation of pristine MoS 2 . The transducer electrode pairs were fabricated using reverse offset printing technique on a piezoelectric LiNbO 3 substrate. The active thin film of MoS 2 flakes was deposited by Electrohydrodynamic atomization (EHDA) while the thin film of PEDOT:PSS was deposited by SAW-EHDA hybrid system. The fabricated sensor is capable of sensing relative humidity with high sensitivity (50 kΩ/%RH or 800 Hz/%RH) in a wide range of 0%RH–80%RH. The response and recovery times are also excellent with values of 0.5 s and 0.8 s respectively. This unique approach of combining multiple transducers in a single sensing device can lead to the development of high performance sensors and can solve the current limitations of single transducer based sensing devices. [ABSTRACT FROM AUTHOR]