The combustion chamber temperature of new-generation aircraft engines can reach an ultrahigh temperature of 1800 °C, making temperature monitoring of key components crucial. Thin-film thermocouples (TFTCs) are highly sensitive and have rapid response times; however, their upper-temperature limit remains below 1800 °C. This study proposes an ultrahigh-temperature film thermocouple, which is enhanced by yttria-stabilized zirconia (YSZ) for positive films, indium oxide (In₂O₃) for negative films, and aluminum oxide (Al₂O₃) for protective films. The thermocouple is designed on the basis of temperature measurement principles, first principles, and simulations, and it is manufactured via screen printing. The results indicate that the maximum working temperature is 1850 °C. In experiments with different doping ratios at 1800 °C, the thermocouple achieves a maximum temperature electromotive force (TEMF) of 258.5 mV and a maximum Seebeck coefficient of 180.9 μV/°C, with an In₂O₃ : YSZ92(ZrO₂ (92 wt%) : Y₂O₃ (8 wt%)) ratio of 9 : 1 in wt%. Through the lumped heat capacity method, the response time was measured at 2.8 ms, which demonstrated good dynamic response characteristics. A film thermocouple was successfully utilized to measure a gas temperature of 1090 °C at the outlet of an air turbine rocket (ATR) engine, confirming its high-temperature operational capability. To improve the repeatability of the TFTCs without affecting their thermoelectric outputs, a convolutional neural network-long short-term memory network (CNN-LSTM)-attention neural network is implemented to mitigate the repeatability errors, achieving a high repeatability of 99.53%. Additionally, the compensated temperature data are compared with those obtained from a standard B-type thermocouple, showing a full-scale error of ±0.73% FS. This study provides a feasible solution for ultrahigh temperature measurements.

High-temperature thin-film thermocouples (TFTCs) have attracted significant attention in the aerospace and steel metallurgy industry. However, previous studies on TFTCs have primarily focused on the two-dimensional planar-type, whose thermal sensitive area has to be perpendicular to the test environment, and therefore affects the thermal fluids pattern or loses accuracy. In order to address this problem, recent studies have developed three-dimensional probe-type TFTCs, which can be set parallel to the test environment. Nevertheless, the probe-type TFTCs are limited by their measurement threshold and poor stability at high temperatures. To address these issues, in this study, we propose a novel probe-type TFTC with a sandwich structure. The sensitive layer is compounded with indium oxide doped zinc oxide and fabricated using screen-printing technology. With the protection of sandwich structure on electrode film, the sensor demonstrates robust high-temperature stability, enabling continuous working at 1200 ℃ above 5 h with a low drift rate of 2.3 ℃·h⁻¹. This sensor exhibits a high repeatability of 99.3% when measuring a wide range of temperatures, which is beyond the most existing probe-type TFTCs reported in the literature. With its excellent high-temperature performance, this temperature sensor holds immense potentials for enhancing equipment safety in the aerospace engineering and ensuring product quality in the steel metallurgy industry.

For the large amount of waste heat wasted in daily life and industrial production, we propose a new type of flexible thermoelectric generators (F-TEGs) which can be used as a large area bionic skin to achieve energy harvesting of thermal energy. With reference to biological structures such as pinecone, succulent, and feathers, we have designed and fabricated a biomimetic flexible TEG that can be applied in a wide temperature range which has the highest temperature energy harvesting capability currently. The laminated free structure of the bionic F-TEG dramatically increases the efficiency and density of energy harvesting. The F-TEGs (single TEG only 101.2 mg in weight), without an additional heat sink, demonstrates the highest output voltage density of 286.1 mV/cm² and the maximum power density is 66.5 mW/m² at a temperature difference of nearly 1000 °C. The flexible characteristics of F-TEGs make it possible to collect the diffused thermal energy by flexible attachment to the outer walls of high-temperature pipes and vessels of different diameters and shapes. This work shows a new design and application concept for flexible thermal energy collectors, which fills the gap of flexible energy harvesting in high-temperature environment.

Flexible temperature sensors have been extensively investigated due to their prospect of wide application in various flexible electronic products. However, most of the current flexible temperature sensors only work well in a narrow temperature range, with their application at high or low temperatures still being a big challenge. This work proposes a flexible thermocouple temperature sensor based on aerogel blanket substrate, the temperature-sensitive layer of which uses the screen-printing technology to prepare indium oxide and indium tin oxide. It has good temperature sensitivity, with the test sensitivity reaching 226.7 μV ℃⁻¹. Most importantly, it can work in a wide temperature range, from extremely low temperatures down to liquid nitrogen temperature to high temperatures up to 1200 ℃, which is difficult to be achieved by other existing flexible temperature sensors. This temperature sensor has huge application potential in biomedicine, aerospace and other fields.