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| Author(s): |
Mayk Rodrigues do Nascimento
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Presidente Prudente. 2022-10-31. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências e Tecnologia. Presidente Prudente |
| Defense date: | 2022-09-02 |
| Advisor: | Neri Alves |
| Abstract | |
The printed electronic shows excellent potential for the development of sensors that can be manufactured in personal adornment, cards and package. Films of zinc oxide (ZnO), obtained by organic precursor solution printed or nanoparticle dispersion, have been widely studied as an ultraviolet radiation (RUV) sensor, gas and vapors. In fact, it is of excellent interest for the understanding of sensors of the base ZnO, among them the humidity sensor. For example, its monitoring is important in metal parts manufacturing industries to prevent corrosion because of the high humidity, or for human permanence environment, in which the low humidity can cause lung infections, allergic crises, sinusitis, among others. In this work shows the development of photoresistor and photodiode based on ZnO. The ZnO films were deposited from the pyrolysis spray technic, this being the active layer of the devices. For the photoresistor, aluminum parallel electrodes were used and the diode used aluminum as an inferior electrode and PEDOT:PSS as a superior electrode. From the measurements of visible-ultraviolet (Uv-Vis) for the ZnO films, a maxima absorption in 355 nm was observed, this being the same emission value of the UV Light emission diode (LED) used in photoresponse measurement. In photoresistors, the relaxation and decay time are controlled by adsorption and desorption of species oxygen. It was observed that in a chamber with a controlled relative humidity of (UR)17%, obtained response time (trep) and recovery time (trec) of 11,6 and 12,1 s respectively and when increasing the UR to 87% these times have reached 67,7 and 124,9 s. The photoresistor showed high sensitivity, reaching 6,6 × 103 when exposed to high humidity. The diode showed the rectification only 4 times for a dry chamber. When the humidity is increased, it presents a rectification of 34 times, being that the increase occurred more significantly in reverse polarization. Under RUV, the diode showed an increase in conductivity which is limited by UR. Both the time (response and recovery) were greater than the photoresistor times because even the electrical measurements showed the stability of PEDOT:PSS in enhancing moisture, it is a factor that makes the adsorption and desorption difficult of gas molecules on the surface of ZnO (AU) | |
| FAPESP's process: | 19/03934-0 - ZnO-based oxygen sensor assisted by UV light |
| Grantee: | Mayk Rodrigues do Nascimento |
| Support Opportunities: | Scholarships in Brazil - Master |