Fabrication and characterization of La0.8Sr0.2CrO3/In2O3 thin film thermocouple for high temperature sensing

Optimizing the Properties of La0.8Sr0.2CrO3 Thin Films through Post-Annealing for High-Temperature Sensing

“…By calculation, the S values of 0.2LSCO-Pt thin-film thermocouples were nearly the same as those of the 0.2LSCO thin films themselves due to the S of Pt being neglected (1.67 V/ • C for standard Pt wire [36]). From our previous article [19], the 0.2LSCO thin film annealed at 1000 • C was very stable, and the draft rate of a 0.2LSCO/In 2 O 3 TFTC was only 0.58 • C/h, which was almost equal to that of a standard type-K wire thermocouple (0.18 • C/h) with a diameter of 0.5 mm. At the same time, combining with the results of the crystal structure, morphology, and electrical conductivity mentioned above, the post-annealing temperature of 1000 • C was more beneficial for high-temperature sensing.…”

“…It is well known that the principle of thermocouples is based on the Seebeck effect, which can be defined as Equation ( 1) [19]:…”

“…Therefore, the development of a new TFTC fabricated by conductive ceramics has been a trend to measure high temperatures in air [12][13][14][15]. Especially, conductive oxides with better oxidation resistance and higher Seebeck coefficients have become the most promising candidate materials of electrodes for TFTCs, such as In 2 O 3 , ITO, ZnO:Al (AZO), and La 1-x Sr x CrO 3 (xLSCO) [14,[16][17][18][19]. When In 2 O 3 and ITO were used to fabricate the electrodes of TFTCs, they had excellent performances with a maximum measurement temperature of 1280 • C, while a serious volatilization problem appeared for them above 1200 • C especially because of the losing of Sn 4+ from ITO, and the indium element is scarce in the earth [20][21][22].…”

“…From our previous work [17], a screen-printed thick-film thermocouple fabricated by LaCrO 3 (LCO) and La 0.8 Sr 0.2 CrO 3 can be used to measure a temperature of 1550 • C for 10 h in air, which has inspired the fabrication of TFTCs by using xLSCO electrodes. Since then, some TFTCs fabricated by the 0.2LSCO thin film have been investigated, such as 0.2LSCO-In 2 O 3 [19] and 0.2LSCO-Pt [33], with a higher sensitivity and stable output voltage versus the temperature difference. However, the properties of 0.2LSCO thin films can be affected significantly by the post-annealing treatment process, which have not yet been investigated systematically and should be studied to fabricate TFTCs with a stable output voltage curve to use at high temperatures.…”

A Flexible Film Thermocouple Temperature Sensor

“…With the rapid development of science and technology, various types of film materials are widely used in production and life [1][2][3][4] . The thin film thermocouple temperature sensor is a new type of sensor born with the development of thin film technology [5][6][7] . Compared with the traditional bulk thermocouple, due to its small device and the thickness of the thermal junction at the micro-nano level, it has the advantages of fast response and small heat capacity [8][9] .…”