Printed sensor systems on flexible substrate
Creators: name: Escobedo Araque, Pablo
Publisher: name: Zenodo
Year: 2018
Subjects: Printed Electronics, Flexible Electronics, Sensor Instrumentation, Colorimetric Sensors, RFID, NFC, Smart Systems

description: The tracking and monitoring of environmental parameters of significant interest such as temperature, humidity, ionizing radiation and substances or gases concentration is a growing demand in different sectors: from personal and clinic healthcare areas to food safety and industrial fields, including applications in the context of Wireless Sensor Networks (WSNs) and Internet of Things (IoT). Besides, the emergence of Printed Electronics (PE) technology has enabled the development of sensing devices on flexible substrates such as paper, textile or plastic foils. Using printing techniques to fabricate electronic devices promises lower production costs because of the additive nature of the technology and the advantage of large-area processes with reduced infrastructure. Printed devices can benefit from their potential advantages to be flexible, thin, lightweight, conformal, transparent, wearable, easy-to-integrate, cost-effective and environmentally friendly. The development of printed sensor devices that are selective, sensitive, with fast response, low cost, low power consumption and connected by means of wireless technologies such as Radio Frequency Identification (RFID) or Near Field Communication (NFC) is an option of great scientific and technological interest. Additionally, it is highly desirable to be able to obtain the information from the sensor systems using general-purpose devices that are readily available to all. The combination of printing technologies and sensor devices with wireless connectivity leads to the next paradigm of smart products. The aim of the thesis is the design, development, fabrication and evaluation of sensor systems fundamentally based on the use of printing technologies on flexible substrate as the main manufacturing process. Methodological objectives include the study, characterization and validation of the main printing techniques used in the development of PE on flexible substrates: inkjet and screen printing. Post-processing of printed patterns are also addressed as an essential step towards achieving conductive structures after the printing process. The main strategies are: - Inclusion of commercially available sensors in passive architectures capable of energy harvesting and remote sensor data transmission by means of wireless technologies such as RFID or NFC. - Integration of novel printed sensors into passive systems with conditioning stages where sensor information can be accessed using RFID/NFC or other wireless mechanisms. - Design of printed sensor systems in which the monitored magnitude causes a variation in the electrical properties of the system that can be remotely detected. - Development of smartphone-based sensor platforms in which mobile devices with custom-designed applications allow the powering, data communication and processing of the associated passive sensor systems. The magnitudes of interest are temperature, humidity, radiation and concentration of different gases related to modified atmosphere and food preservation. The outcomes of this work will be passive sensor systems in the form of smart RFID/NFC tags or other simple and low-cost sensor platforms with feasibility to be used in fields such as environmental assessment, healthcare monitoring and smart packaging applications.