NiPc:Borophene hybrid organic field-effect transistor based gas sensors

We report the preparation and characterization of an Organic Field-Effect Transistor (OFET) gas sensor based on a hybrid active layer composed of Nickel Phthalocyanine (NiPc) and beta-phase borophene prepared via physical exfoliation. The electrical properties and time-dependent stability of NiPc:Borophene hybrid OFETs were evaluated. According to the root I-D-V-G analysis obtained from transfer measurements, the device exhibits ambipolar behavior, with threshold voltages approximately V-th p= - 40.8 V and V-th,V-= + 40.8 V the on/off current ratio is similar to 1.0 x 10(6) in both polarities. To assess the long-term electrical stability of the prepared NiPc:Borophene NiPc: Borophene hybrid OFETs, time-dependent bias-stress measurements were investigated. Under negative bias-stress measurements, the change in Delta V-T increased significantly (Delta V-T = 0.195 V at 10(3) s, and 0.336 V at 10(4) s); the mobility stability was 98,7 % at 10(3) s, and 97,5 % at 10(4) s; and the normalized current (I-D/I-D0) was 0.92 % at 10(3) s, and 0.86 % at 10(Han et al., 2018(4)). Beside these, under positive bias-stress measurements, the change in Delta V-T remained limited (Delta V-T = 0.045 V at 10(3) s, and 0.077 V at 10(4) s); the mobility stability was 99,6 % at 10(3) s, and 99,2 % at 10(4) s; and the I-D/I-D0 was 0.97 % at 10(3) s, and 0.95 % at 10(Han et al., 2018(4)). Because the changes in mobility and normalized current values were limited, it was concluded that the overall performance of the OFETs was maintained under long-term stress. Gas sensing performance was evaluated for NO2, NH3, and ethanol at room temperature. The sensitivities were found to be 21.39 % ppm(-1) for NO2, 5.84 % ppm(-1) for NH3, and 4.07 % ppm(-1) for ethanol. The highest slope for NO2 is consistent with its electron-withdrawing nature, which increases the hole density in the p-type channel and strongly triggers current or resistance changes. LOD values drop to as low as 0.13 ppm for NO2; NH3 and ethanol are 0.62 ppm and 1.10 ppm, respectively. The peak response to NO2 is maintained at similar to 25 % for three consecutive cycles, with no significant shift between cycles. This demonstrates the sensor's strong reproducibility and reversible adsorption-desorption capabilities. The NiPc:Borophene hybrid OFET sensor shows promise for use in low-power, scalable, and highly responsive environmental monitoring systems.