I. Core Research Summary

• Dual-mode integrated sensing structure

The same device integrates a serpentine gold strain gauge and a gold/ITO thin-film thermocouple, enabling AC‑signal measurement of strain resistance and DC Seebeck‑voltage measurement of temperature. This allows for in‑situ, real‑time compensation of temperature‑induced strain drift, eliminating the need for complex external decoupling algorithms. The thermocouple exhibits a thermoelectric sensitivity of 51.6 μV/°C, while the strain gauge has a gauge factor of 2.5; the overall performance surpasses that of commercial patch‑type sensors.

• Millisecond-scale photon-flashing low-temperature sintering process

The entire sintering process takes less than 2 seconds; xenon‑lamp irradiation selectively heats and raises the temperature of the nano‑conductive layer, while the PI flexible substrate remains at a low temperature throughout, eliminating the warping and aging of the substrate that result from conventional high‑temperature baking lasting several hours. Meanwhile, gold and ITO film particles achieve thorough fusion, significantly enhancing electrical conductivity and continuity.

• Ultra-wide, high-temperature-stable service range

The sensor can stably operate at 350°C over long periods; after 15 days of continuous high‑temperature immersion and seven thermal cycling cycles, its thermoelectric output and strain‑gauge resistance exhibit virtually no drift. Following 500 bending/torsion cycles, the sensing performance degrades by less than 5%, and after 10,000 bending cycles, the performance reduction is only 7%, demonstrating outstanding mechanical durability.

• Multi-substrate universal compatible printing system

The aerosol‑based process is compatible with four types of substrates—polyimide, polyurethane, mica, and glass—and can be used to flexibly fabricate both flexible and rigid sensing units tailored to the curvature and material properties of various devices, making it suitable for a wide range of industrial monitoring components.

• Digital Maskless Rapid Development

With CAD, the strain gauge’s length and width, as well as the thermocouple dimensions, can be modified with a single click; gold and ITO inks can be rapidly switched via atomization, eliminating the need for photolithographic masks. This enables the rapid fabrication and iterative optimization of novel high-temperature sensing samples within just a few hours.

II. Complete Preparation Process and Core Advantages of Aerosol Spraying

(1) Complete Dual-Mode Sensor Production Process

• PI flexible substrate undergoes plasma cleaning to remove oil and contaminants, ensuring film adhesion.
• Ultrasonic atomization of gold nanoparticle ink, aerosol‑based CNC printing of a serpentine strain gauge and a thermoelectric electrode on one side;
• Switch to ITO nanoink, print the electrode on the opposite side in a crosswise pattern, and form a temperature-sensing junction at the Au/ITO interface.
• Xenon‑gas pulsed flash sintering system, 2 kV voltage, 800 µs pulse duration, three‑shot flash sintering, with total sintering time under 2 seconds.
• After cooling, four‑wire electrical calibration was performed, and simultaneous thermal‑strain testing was completed using a high‑temperature muffle furnace and a cantilever beam platform.

(II) Five Core Process Advantages (Comparison with Lithography, Screen Printing, and Conventional Thermal Sintering)

• In-situ integrated molding of multiple materials eliminates the need for multiple patching steps.

The same device enables continuous printing of both strain‑sensing and temperature‑sensing circuitry in a single layer, featuring an integrated dual‑mode sensing unit with adhesive‑free delamination and an air‑gap thermal insulation layer, resulting in a substantial improvement in measurement accuracy.

• Ultrafast photonic sintering, with zero thermal damage to flexible substrates.

Unlike conventional ovens that subject materials to high‑temperature heating for hundreds of minutes, flash heating relies solely on the heat absorption of metallic nanoparticles, leaving the polymeric substrate unaffected by thermal shock and ensuring that the ultra‑thin, flexible film retains its shape.

• Micron-level high-precision conformal printing, compatible with irregularly shaped curved components.

Aerosol printing with a 3–5 mm tolerance in print pitch enables direct deposition of sensing circuits on turbine blades and curved pipe outer surfaces, where conventional patch‑on methods struggle to conform to complex geometries.

• Broad substrate compatibility; both soft and rigid components can be fabricated.

PI, PU, mica, and glass all share a single set of printing parameters, balancing the needs of flexible wearable devices with those of rigid high‑temperature industrial component monitoring.

• Maskless digital R&D significantly reduces trial-and-error costs.

No custom lithography masks are required; by adjusting the strain‑grid layout, new samples can be produced on the same day, shortening the iterative cycle for high‑temperature sensing formulations by 80%.

III. Five Key Technological Innovations

Innovation 1: A novel fabrication system combining aerosol-based multi-material direct writing with photonic flash processing.

Innovation 2: An in-situ thermoelectric self-compensation architecture that eliminates high-temperature strain‑induced temperature drift.

Innovative selective photothermal sintering mechanism, balancing high electrical conductivity with flexible substrate protection.

Innovative 4 350℃ long-term stable high-temperature-resistant sensing system

Innovation: Standardized Process for Universal Curved-Surface Conformal Sensing

IV. Existing Process Challenges and Corresponding Solutions for Overcoming Them

Challenge 1: There is a gap between the split-type strain gauge and the thermocouple during bonding, leading to significant temperature-compensation errors.

Challenge 2: Conventional oven-based thermal sintering is time-consuming and, at high temperatures, can degrade flexible substrates such as PI.

Challenge 3: Conventional printed films are prone to oxidation at high temperatures, leading to a decline in long-term service performance.

Challenge 4: Lithography and screen printing can only perform planar processing, making it impossible to deploy sensors on curved surfaces such as turbines and pipelines.

Challenge 5: Multimodal sensor fabrication is complex, and the development cycle for new products can extend to several weeks.

V. Future Diversified Industrial Application Scenarios

1. High-Temperature Monitoring of Aeroengine Turbine Blades

2. Structural Monitoring of High-Temperature Piping in Thermal and Nuclear Power Plants

3 Soft-Robotics–Inspired Flexible Sensing

4. Monitoring of Power Battery Packs for New Energy Vehicles

5. High-Performance Sensing Rapid Prototyping Platform for Universities

Figure 1. Schematic illustration showing: (a) the AJP‑based structure of a multimodal sensor on a polyimide substrate; (b) the IPL sintering process and sintering conditions for the printed film; (c) optical images of the sensor printed on a flexible polyimide substrate, along with high‑magnification views of localized regions of the printed thermocouples and strain sensors; (d) applications of aerosol‑jet‑printed sensors subjected to IPL sintering on other substrates: (i) a multimodal sensor on a glass substrate; (ii) a printed thermistor on a PUD substrate; (iii) a strain gauge on a mica substrate.

Figure 2. Scanning electron microscope images of gold and ITO materials fabricated by aerosol jet printing illustrate the surface morphologies of the following samples: (a) unsintered gold; (b) IPL‑sintered gold; (c) gold sintered at 800°C; (d) unsintered ITO; (e) IPL‑sintered ITO; (f) ITO sintered at 800°C. The figure also shows the electrical conductivity values of IPL‑sintered gold (g) and ITO (h) at different pulse durations, with error bars representing the standard deviation across five samples.

Figure 3. (a) Thermoelectric response of printed Au/ITO thermocouples during heating and cooling; (b) Stability of temperature measurements; (c) Comparison of the thermoelectric voltage output of IPL-sintered sensors versus thermally sintered sensors as a function of temperature difference. Sensors 1–3 are all IPL-sintered.

Figure 4. Synchronous measurements of temperature and strain under room-temperature (RT) and elevated-temperature conditions. Relative resistance changes of the strain gauge at different strains: (a) at room temperature; (b) a comparison of test results between the thermosensitive sensor and the IPL-sintered sensor at room temperature, along with the performance of this sensor at (c) 200°C and (d) 350°C.

Table 1. Comparison of Various Parameters of Strain Gauges in the Literature

Figure 5. Performance of the multimodal sensor before and after 15 days of thermal aging at 350°C. Thermoelectric voltage output as a function of temperature difference: (a) variation before and after thermal aging; (b) variation after multiple heating–cooling cycles. Strain‑gauge resistance: (c) variation before and after thermal aging; (d) variation during repeated thermal cycling.

Figure 6. (a) Performance of the printed temperature sensor before and after 500 bending–twisting cycles, and (b) performance of the strain gauge before and after 500 bending cycles.