Since the material is thermoelectric, it is also possible to measure temperature changes: the larger the temperature difference between the warm and cold sides, the higher the voltage developed. The humidity affects how rapidly the ions move from the warm side to the cold one. If the humidity is zero, no ions are transported.
"What is new is that we can distinguish between the thermoelectric response of the electrons (giving the temperature gradient) and that of the ions (giving the humidity level) by following the electrical signal versus time. That is because the two responses occur at different speeds", says Xavier Crispin, professor in the Laboratory of Organic Electronics and principal author of the article published in Advanced Science.
"This means that we can measure three parameters with one material, without the different measurements being coupled", he says.
Shaobo Han, doctoral student, and Senior Lecturer Simone Fabiano at the Laboratory of Organic Electronics, have also found a way to separate the three signals from each other, such that each can be simply read individually.
"Our unique sensor also prepares the way for the internet of things, and brings lower complexity and lower production costs. This is an advantage not least in the security industry. A further possible application is placing sensors into packages with sensitive goods", says Simone Fabiano.
COMPAMED-tradefair.com; Source: Linköping University