Gas-Sensing Performance and Operation Mechanism of Organic π-Conjugated Materials

Organic π-conjugated materials, which have advantages of tailorable chemical structures, solution processability, and mechanical flexibility, are promising candidates for applications in low-cost, portable gas sensors that operate at room temperature. Nevertheless, there are still challenging issues in the development of organic semiconductor gas sensors because of issues such as relatively poor sensitivity, slow response, and low recovery. Herein, we summarize the recent progress of gas sensors based on organic conjugated materials and discuss the critical factors related to the sensor performance and the operation mechanism. We highlight six types of typical materials from small molecule to polymer semiconductors with respect to their performance in detecting different gas species through morphology control and molecular engineering. Critical factors from gas kinetics to sensor-analyte interaction are briefly discussed, together with an examination of sensing mechanisms.