An Ultrasensitive Organic Semiconductor NO₂ Sensor Based on Crystalline TIPS‐Pentacene Films

Abstract

Organic semiconductor gas sensor is one of the promising candidates of room temperature operated gas sensors with high selectivity. However, for a long time the performance of organic semiconductor sensors, especially for the detection of oxidizing gases, is far behind that of the traditional metal oxide gas sensors. Although intensive attempts have been made to address the problem, the performance and the understanding of the sensing mechanism are still far from sufficient. Herein, an ultrasensitive organic semiconductor NO sensor based on 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-petacene) is reported. The device achieves a sensitivity over 1000%/ppm and fast response/recovery, together with a low limit of detection (LOD) of 20 ppb, all of which reach the level of metal oxide sensors. After a comprehensive analysis on the morphology and electrical properties of the organic films, it is revealed that the ultrahigh performance is largely related to the film charge transport ability, which was less concerned in the studies previously. And the combination of efficient charge transport and low original charge carrier concentration is demonstrated to be an effective access to obtain high performance organic semiconductor gas sensors.

Gas Sensors Based on Nano/Microstructured Organic Field‐Effect Transistors

“…Chi's group have fabricated nitrogen dioxide (NO 2 ) sensors based on a high‐quality crystalline 6,13‐bis(triisopropylsilylethynyl)pentacene (TIPS‐Pentacene) film by thermal deposition (Figure h). Figure i,j illustrates the dynamic response of a 7.5 nm TIPS‐Pentacene/p‐6p sensor device with various NO 2 concentrations, which shows an ultrahigh sensitivity exceeding 1000% ppm −1 at several ppm and a calculated LOD of 20 ppb . In addition, this work provided a comprehensive discussion on the relationship between the charge transport and the sensor performance of the film.…”

“…h) Representation of sensor device and the molecular structures of TIPS‐pentacene and p‐6P; i) response curve of a 7.5 nm TIPS‐pentacene/p‐6P film with exposure to NO 2 gas; j) responsivity (R) and sensitivity of the above device. Reproduced with permission . Copyright 2017, Wiley‐VCH.…”

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

“…[61] The experiment observation confirmed the chemisorption of NO 2 on the Cu atom with low dose of analyte, while high dose of NO 2 resulted in an irreversible absorption, which on some extent explained the poor recovery problem. [38] transistor (I gas -I 0 )/I 0 160000 % @30 ppm 415 ppb NO 2 SO 2 , NH 3 , H 2 S, CO 2 NA CuPc thin film [25] transistor (I gas -I 0 )/I 0 241 %@30 ppm 1 ppm NO 2 SO 2 , NH 3 , H 2 S NA CuPc thin film [22] resistor (I gas -I 0 )/I 0 14000 %@35 ppm 180 ppb Cl 2 NA NA CuPc single crystal [39] transistor (I gas -I 0 )/I 0 750 %@20 ppm 0.5 ppm SO 2 NA 3 min/16 min CuPc thin film [24] transistor (I gas -I 0 )/I 0 39 %@100 ppm H 2 S SO 2 , CH 4 , H 2 , CO 2 NA ZnPc single crystal [40] transistor (I gas -I 0 )/I 0 220 %@10 ppm NA NO 2 SO 2 , H 2 S NA VOPc [41] resistor (I gas -I 0 )/I 0 1500 % @10 ppm NA NO 2 NA 30s/16 min Pentacene [43] transistor (I gas -I 0 )/I 0 3000 %@10 ppm 100 ppb NO 2 CO, CO 2 , N 2 O, NH 3 < 1 min Pentacene [44] transistor μ/μ 0 30 % @1 ppm 0.5 ppm NH 3 CO 2 , C 2 H 5 OH, CH 4 , CH 3 COCH 3 1000 s/- [45] [42] resistor (I g À I 0 )/I 0 650 % @30 ppm…”

“…Dynamic testing results and sensing curve of pentacene and TIPSpentacene to NO 2 . Reproduced with permission from ref [45],. Copyright 2017 Wiley-VCH…”

Hierarchical Self‐Assembly of Tetrakis(1‐pyrenyl)porphyrins into Microscopic Petals and Flowers with Ultrasensitive Room‐Temperature NO2 Sensing in a Broad Humidity Range

“…Compared with the most inorganic compounds, organic semiconductor materials as the chemically sensitive component of chemical/conductometric transduction systems have been emerged and become the promising candidates for gas sensors due to their advantages in terms of tunable molecular structures, great processability, low cost production, selective detection and especially low operating temperature. [5][6][7][8] Among the large family of organic semiconductor materials, tetrapyrrole derivatives including porphyrins and phthalocyanines with large π-conjugated electronic molecular structures have attracted considerable research interest owing to their high thermal and chemical stability and rich substitution chemistry as well as strong π-π intermolecular interaction in solid state, resulting in intriguing electronic and optical properties [9] and potential applications as gas sensor. [4,[10][11][12][13][14] For example, a vacuum deposited film of cobalt phthalocyanine is revealed to exhibit a quite stable response and discrimination between 12, 25 and 50 ppm of NH 3 over the 10-70% RH range.…”