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Infrared imaging helps us see things the human eye cannot. The technology—which can make visible body heat, gas leaks or water content, even through smoke or darkness—is used in military surveillance, search and rescue missions, health care applications and even in autonomous vehicles.

These capabilities come with an engineering challenge, however. Infrared cameras need electrical contacts to capture and transmit the images they detect. Most materials that can conduct electrical signals also block the majority of infrared radiation from reaching the sensor, creating a fundamental conflict between seeing infrared light and having the electrical connections needed to process that information.

To solve this, researchers at NYU Tandon School of Engineering have developed a transparent electrode made from embedding tiny silver wires, similar in width to human hair, into a transparent plastic matrix that can be simply deposited on top of conventional infrared detectors.

The research, published in the , tackles a key challenge in infrared detector manufacturing.

"We've developed a material that solves a fundamental problem that has been limiting infrared detector design," said Ayaskanta Sahu, associate professor in the Department of Chemical and Biomolecular Engineering (CBE) at NYU Tandon and the study's senior author.

"Our transparent electrode material works well across the infrared spectrum, giving engineers more flexibility in how they build these devices."

The researchers tested their material by building it into infrared cameras that use colloidal quantum dots as the light-responsive material. These are tiny engineered particles that have recently gained attention for their use in quantum dot televisions and their role in earning the 2023 Nobel Prize in Chemistry.

For this study, the group specifically used tiny clusters of mercury telluride, a type of quantum dot that responds to various wavelengths of infrared light.

Their new approach represents a significant improvement over existing methods. Traditional infrared photodetectors have relied on expensive materials like indium tin oxide (ITO) or thin metal films, which either lose transparency at longer infrared wavelengths or suffer from poor electrical properties and must be rigid.

Measuring 120 nanometers in diameter and 10–30 micrometers in length, the silver nanowires form conductive networks even at relatively low concentrations. When embedded in the PVA matrix, they form a silvery conductive ink that can be sprayed or spun onto infrared detectors as stable and flexible films that can even be manufactured at the low temperatures needed for quantum dot processing.

"Conventional electrodes in the infrared are like blackout curtains—most of the signal never reaches the sensor," said graduate researcher Shlok J. Paul, a co-author of the study.

"Our near-invisible web of silver nanowires lets more infrared photons in while doubling as the wiring that carries the electrical current needed to turn the invisible light into data. While there is more work to be done, the simplicity of this flexible layer could carry IR detection from the lab to commercial applications like for firefighter vision or self-driving cars."

The researchers filed a covering their method for embedding silver nanowires in a polymer matrix for transparent infrared electrodes.