OFET (Organic Field Effect Transistor) ammonia gas sensor containing functional insulation layer

Abstract

The invention discloses an OFET (Organic Field Effect Transistor) ammonia gas sensor containing a functional insulation layer. The OFET ammonia gas sensor comprises a substrate, an insulation layer a, the functional insulation layer, an insulation layer b and an organic semiconductor layer which are sequentially arranged from bottom to top, wherein the organic semiconductor layer is provided with a source electrode and a drain electrode; a gate electrode is arranged between the substrate and the insulation layer a; the insulation layer a and the insulation layer b are formed by polymer insulation materials which do not contain hydroxyl; the functional insulation layer is formed by a polymer insulation material which contains the hydroxyl. According to the OFET ammonia gas sensor disclosed by the invention, a functional insulation layer material containing the hydroxyl is introduced between two insulation layers, so that the gas sensing property of an OFET is increased; -OH contained in the hydroxyl in the functional insulation layer can be subjected to reversion when ammonia gas molecules permeate into an interface of the insulation layers / the organic semiconductor layer, so that hole charges in corresponding number can be induced, parameters of saturation current, a migration rate and the like of devices are enabled to change, and detection on ammonia gas can be realized.

Description

technical field [0001] The invention belongs to the technical field of sensor preparation, in particular to an organic field effect tube ammonia sensor with a functional insulating layer. By adding a hydroxyl-containing polymer insulating layer to the gas sensor, it can not only improve the detection ability of ammonia gas, but also greatly improve the environmental stability of the device. Background technique [0002] With the rapid development of electronics and its application in the field of sensors, chemical sensors based on field effect transistors have become a research hotspot in the field of sensors, and their application to the detection of inorganic and volatile gases has been widely reported. Compared with the traditional gas sensor, the gas sensor based on the field effect tube structure has several notable advantages in addition to the advantages of high sensitivity and usability at room temperature: [0003] 1) Use the basic characteristics of transistors to...

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Problems solved by technology

[0007] However, most of the existing field effect tube gas sensors can work stably in the atmospheric environment. Most of them are silicon-based field effect tubes. When used in large quantities, they will pollute the environment, the preparation process is complicated, the cost is expensive, and it is difficult to realize flexible and large-area devices. In contrast, polymer insulating materials are cheap, easy to prepare, and easy to prepare large-area flexible devices, but they are easily denatured in the air, especially polymer insulating materials containing hydroxyl groups are very easy to combine with water molecules; at the same time , as an important part of the field effect tube insulation layer, the polymer insulation material can be prepared by solution method, and a good quality film can be formed at low temperature. The polymer material containing hydroxyl group can also use water and alcohol solvent system, Further reduce the harm to the environment

[0008] The existing organic field effect tube ammonia sensor based on p-type organic semiconductor materials, when detecting ammonia, its parameters change in a negative direction, that is, the saturation current and mobility decrease, and the threshold voltage drifts negatively. recovery performance, but under high-strength and high-concentration detection environment, it is very easy to be poisoned, resulting in device failure

The organic field effect tube ammonia sensor based on n-type organic semiconductor materials is rarely used because of its inherent deficiencies in air stability.

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