Fully Integrated Organic Field-Effect Transistor Platform to Detect and to Quantify NO 2 Gas

Herein, the gas sensing characteristics of PDVT-10 organic field-effect tran sistor(OFET) devices are explored and integrated to build a compact analog-to-digitalconverter (ADC) gas detection system. The electrical characteristics of thepristine PDVT-10 OFET exhibitIon/Ioffratio and threshold voltage as 104and12 V, respectively. Through the coatin g of a metal-organic framework (MOF) onthe surface of PDVT-10, theIon/Ioffimproves by one order of magnitudeaccompanied by significant positive threshold shift measured around 4 V. MOF isadded as a pre-concentrating material, and the device exhibits excellent selectivityand good sensitivity toward the target NO2gas. Most of the reports available inthe literature generally focus on the gas sensing performance of individualsensors, which does not have the potential to solve real-time sensing problems.Hence, for the first time, a fully integrated ADC system is designed with just twoOFETs. The integrated ADC system not only detects the NO2gas with highsensitivity and selectivity but also generates a 5 bit digital output correspondingto different NO2gas concentrations from 25 ppb to 1 ppm.