ZnO-based electrolyte-gated transistor (EGT) applied as multiparametric UV-sensing device

Transistors based in solution-processable semiconducting metal oxides stands out for disposable, printed and wearable electronics. Here we report a transparent and printed ZnO-based electrolyte-gated transistor (EGT), using cellulose electrolyte, which exhibited low-voltage operation, below 2 V, threshold voltage of 0.16 V, high on-state current of 0.3 mA, Ion/Ioff ratio of 3.0 × 105 and field-effect mobility of 0.17 cm²/Vs. We have demonstrated that such EGT can be applied as an ultraviolet sensing device, showing multiparametric response with shift in its: threshold voltage (VT), subthreshold swing (S), transconductance (gm) and enhancement in the field-effect mobility in saturation regime (μs) when exposed to different UV irradiance levels. This device achieves high IUV/Idark ratio, responsivity and EQE of 1 × 105, 8.4 × 104 A/W and 2.7 × 106%, respectively, presenting very stable properties when tested in ambient atmosphere, without encapsulation, and with no visible effects of ageing during the period of observation. The variation in the transistor parameters and the high values of the figures of merit for photodetectors, categorize this EGT as a multiparametric UV sensor with good performance and compatible with printed and transparent electronics.