According to foreign media reports, scientists at the Organic Electronics Laboratory have recently developed a sensitive, transparent and printable ultra-sensitive thermal sensor. According to reports, the ultra-sensitive thermal sensor is designed based on thermoelectric materials. When there is a temperature difference between the two sides, the electrons in the thermoelectric materials move from the cold side to the warm side and then produce a voltage difference. However, it should be noted that in this current project, researchers have developed a thermoelectric material, which uses ions instead of electrons as charge carriers, making the effect 100 times greater than that of electrons.
Specifically, compared with 10 mV/K using ionic materials, the thermoelectric materials using electrons can produce 100 mV/K (microvolts per Kelvin), so that the signal is 100 times stronger. In other words, a small temperature difference can produce a strong signal.
Linkping University researcher Dan Zhao, one of the three leading authors of the article, discovered this new material, an electrolyte composed of several ionic polymer gels. Some components are p-type polymers, in which positively charged ions carry currents, which have been well known in previous work. However, she also discovered a highly conductive n type polymer gel, where negatively charged ions have electric current. So far, few such materials have been available.
With the help of the research results of electrolyte in printed electronic products, researchers have developed the first printed thermoelectric module using ions as charge carriers in the world. The module is composed of connected N and P legs, in which the number of leg connections determines the intensity of signal generation. Scientists have used screen printing to fabricate a highly sensitive thermal sensor based on different complementary polymers. Thermal sensor has the ability to convert small temperature difference into strong signal: the module with 36 connecting branches provides 0.333V when the temperature difference is 1K.