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

Abstract

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.

Robust High‐Capacitance Polymer Gate Dielectrics for Stable Low‐Voltage Organic Field‐Effect Transistor Sensors

“…The observed decrease in I SD is likely due to NH 3 molecules diffusing into the conductive channel at the OSC/dielectric interface and donating electrons via a charge transfer reaction, which decreases the number of charge carriers (holes) . 44 Furthermore, the I SD responses remained stable after five continuous cycles of dynamic ammonia exposure over a period of more than 10 h at various levels of %RH as shown in Figure 3b (Figure S11, Supporting Information, for change in current response vs time). The improved sensitivity at higher RH has been previously assigned to the mixture of ammonia and water forming ammonium hydroxide, which enhances the magnitude of Δ I res / I 0 (%) response of the device 45…”

Organic Heterojunction Devices Based on Phthalocyanines: A New Approach to Gas Chemosensing

“…The application of MPc in gas sensors can be traced back to late 1980s in the pioneering work of Jones et al, reporting the very high responses and ultrafast kinetics (a few s) of PbPc-based chemiresistors towards NO 2 obtained by thermal cycling at 300 °C [ 37 ]. In the subsequent years, extensive reviews on OFET devices utilizing MPc materials were reported [ 8 , 38 ] including one by us which focused in particular on gas sensor applications [ 39 ]. MPc-based chemiresistors were extensively studied by Kummel and coworkers to detect a large group of electron-donating gas analytes [ 40 ].…”

“…A common example is OLEDs, which is widely used in new generations of flat panel color displays in products like televisions, monitors, smartphones, tablets and hosts of wearable electronics while OPVs are increasingly being recognized as a potential alternative to conventional expensive silicon-based photovoltaics [ 7 ]. Chemical sensors are another widely researched area inviting numerous studies on organic semiconductors owing to their advantages of low cost and flexibilities of chemical design, synthesis and processing [ 8 ].…”

Electron Beam Induced Tailoring of Electrical Characteristics of Organic Semiconductor Films

“…The flexibility makes organic film based electronic devices superior over its inorganic counter parts. For flexible device applications such as power sources [74,75], displays [76], electronics [77], super capacitors [78], gas sensors [79][80][81], thermoelectric power generators [82,83], organic light emitting diodes [84,85], radiation dosimeters [86][87][88] etc., organic semiconductors are promptly used. The nature of interaction between high energy EB and organic materials depends on the energy as well as dose of the incident EB [7].…”