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Evaluation of the degradation of OTFTs as a function of direct current polarization (D.C.) or alternate (A.C.)

Grant number: 18/14979-2
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): September 01, 2018
Effective date (End): August 31, 2019
Field of knowledge:Engineering - Electrical Engineering
Cooperation agreement: SABESP
Principal Investigator:Fernando Josepetti Fonseca
Grantee:José Diogo da Silva Oliveira
Home Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Company:Universidade de São Paulo (USP). Escola Politécnica (EP)
Associated research grant:13/50440-7 - Online water quality analysis (ACQUA-OnLine), AP.PITE

Abstract

1661/5000Factor limiting the efficiency in photovoltaic and electroluminescent devices (OLEDs), the susceptibility of organic semiconductors to the operating conditions and impurities has direct application in chemical sensors. On the other hand, as OTFTs perform compatible with devices already commercialized for purposes other than sensing, the instability of the transistor exposed to the atmosphere, as well as under constant electric polarization, becomes undesirable. Currently a major effort has been employed in the synthesis of new materials combining high field effect mobility (¼FET) and stability under normal atmospheric conditions. The two main materials that serve as reference are the acenos (such as the small molecule of pentacene) and thiophenes (such as the polymer P3HT) [1]. The first way of studying the degradation of TFT is through the controlled irradiation of the semiconductor [2]. Alternatively, the degradation can be quantified through the electrical characterization of the device [3, 4]. Known as bias stress, in such experiments, a constant or alternating signal is applied to the TFT electrodes for a period of time and the current, as well as the main parameters of the transistor, are monitored. In this context, a study is proposed to evaluate the degradation of OTFTs as a function of continuous (D.C.) or alternating (A.C.) electric polarization. Based on the knowledge acquired in this project, it will be possible to estimate the lifetime of the electronic nose operating under conditions of lower possible operating voltage that guarantees the detection of contaminants in parts per billion (ppb) concentration.