TPU chemists proposed a technology for laser 'tuning' of composites for flexible electronics

• Main
• News
• Science
• TPU chemists proposed a technology for laser "tuning" of composites for flexible electronics

TPU chemists proposed a technology for laser "tuning" of composites for flexible electronics

Researchers at Tomsk Polytechnic University have proposed a universal laser processing technology that can create two materials fundamentally different in terms of functions from a single sample - a copper composite and a copper hybrid with laser- induced graphene. Materials obtained by this method are durable, flexible, resistant to oxidation and do not require additional protective coatings.

The research was supported by a grant of the Russian Science Foundation (No.23-42-00081). The research findings have been published in the journal ACS Applied Materials & Interfaces (Q1, IF: 8,3).

Laser processing of nanomaterials and selective laser sintering are promising methods to manufacture flexible electronics. They make it possible to precisely, efficiently, and scalably impart certain properties to a material (for example, conductivity). This method underlies the creation of flexible devices for strain and temperature sensors, as well as antennas. However, after such processing materials remain mechanically unstable, they oxidize and have poor adhesion to the substrate, making the device vulnerable to breaking during bending, water ingress, and so on.

Chemists from the TERS-Team research group at the TPU Research School of Chemical and Biomedical Technologies have proposed a new single-stage method for laser processing of copper nanoparticles on a polymer substrate (PET). Depending on the laser parameters, the workpiece can be transformed either into a copper polymer composite with a protective shell, or into copper-containing laser-induced graphene on a flexible PET substrate.

To impart certain properties to a material, our technology uses precisely controlled laser power and processing mode of copper nanoparticles. Thus, at moderate laser power, copper nanoparticles melt and encapsulate in a polymer, forming an oxide-free copper composite with low resistance and high immunity to humidity and temperature. Increasing laser power stimulates hybrid formation where copper nanoparticles act as catalysts and help to form laser-induced graphene directly in PET. At the same time, the conductivity and flexibility of the material are preserved,

- notes Raul Rodriguez, one of the authors of the study, professor of the TPU Research School of Chemical and Biomedical Technologies.

The results of chemical and structural analysis showed that the materials modified using TPU technology remained stable for 100 bending cycles at a constant relative humidity of >95% and a temperature of 70 °C for three days and at a relative humidity of >95% and a temperature of 40 °C for 10 days, which shows good stability of the obtained structures.

Using the new processing method, the TPU researchers have created flexible sensors based on nickel, copper, and laser-induced copper graphene. The results of the study showed that the electric and thermoelectric characteristics of the materials are comparable or better than a number of existing PET polymer-based materials.

The technology we proposed scales easily. At the same time, we can process both individual pixels of tens of microns in size, and entire areas of square centimeters. This allows us to select and adjust the properties of materials based on the desired functions of the future device. We used this property to create a flexible thermocouple, where each of the ends is created from copper nanoparticles and differs only in laser processing parameters,

- adds Evgeniya Sheremet, one of the authors of the study, professor at the TPU Research School of Chemical and Biomedical Technologies.

In the future, the technology of the TPU researchers may form the basis for materials for high-capacity sensors and thermosensitive devices.