Mesoporous cellulose nanofibers-interlaced PEDOT:PSS hybrids for chemiresistive ammonia detection

Chemiresistive ammonia (NH₃) detection at room temperature is highly desired due to the unique merits of easy miniaturization, low cost, and minor energy consumption especially for portable and wearable electronics. In this regard, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) has sparked considerable attention due to the benign room-temperature conductivity and environmental stability, but it is undesirably impeded by limited sensitivity and sluggish reaction kinetics. To overcome these, we incorporated cellulose nanofibers (CNF) into PEDOT:PSS via a facile blending. The constituent-optimized composite sensor displayed sensitive (sensitivity of ∼7.46%/ppm in the range of 0.2-3 ppm), selective, and stable NH₃ sensing at 25 °C at 55% RH, with higher response and less baseline drift than pure PEDOT:PSS counterparts. Additionally, the response/recovery times (4.9 s/5.2 s toward 1 ppm NH₃) ranked the best cases of conducting polymers based NH₃ sensors. The humidity involved more than twofold response enhancement indicated a huge potential in exhaled breath monitoring. Furthermore, we observed an excellent flexible NH₃-sensing performance with bending-tolerant features. This work provides an alternative strategy for trace NH₃ sensing with low power consumption, superfast reaction, and high sensitivity.