Revolutionizing Sensing Technology: Embracing Affordable Fully Printed Infrared Sensors

The world of high-end surveillance, medical imaging, and environmental monitoring has long been held back by a single, frustrating factor: cost. While the camera in your smartphone can capture stunning visible light photos for a few dollars, sensors that can "see" in the infrared (IR) spectrum—vital for seeing through smoke or diagnosing health issues—often cost thousands.

A series of groundbreaking studies, recently published in ACS Nano and Advanced Functional Materials, is set to change that. Researchers have developed a way to fully print high-performance infrared detectors using "functional inks" made from lead sulfide (PbS) nanocrystals

The Breakthrough: Printing High-Tech Sensors

Traditionally, making infrared sensors requires expensive, high-temperature manufacturing. By using colloidal nanocrystals, scientists have found a way to "print" these devices at room temperature.

Why This is a Game-Changer:

Extreme Affordability: The materials for a single detector cost less than 20 cents per square centimeter.
Lightning Speed: Using automated robotic systems, a detector can be printed in just 14 seconds.
Minimal Waste: Unlike traditional methods that "wash away" expensive materials, these printed drops use nearly 100% of the active material.

Comparison of Printing Approaches

Feature	All-Inkjet Printing	Robot & 3D Printing
Method	Precise layer-by-layer jetting.	3D frame with a single robotic drop.
Production Time	~3 minutes per detector.	~14 seconds per detector.
Scalability	Limited by nozzle clogging.	Highly scalable for large arrays.
*Detectivity ( $D^$ )**	$\sim2\times10^{10}$ Jones.	$\sim2\times10^{12}$ Jones.

The Future: From Lab to Living Room

This isn't just a laboratory curiosity. Because these sensors can be printed directly onto delicate silicon chips (CMOS), we are on the verge of seeing low-cost infrared cameras integrated into everyday technology

. From safer self-driving cars that can see in the dark to affordable medical imagers for clinics, the future of vision is being printed one drop at a time.

Sources:

YousefiAmin, A., et al. (2019). "Fully Printed Infrared Photodetectors from PbS Nanocrystals with Perovskite Ligands." ACS Nano.
Killilea, N., et al. (2019). "Pushing PbS/Metal-Halide-Perovskite Core/Epitaxial-Ligand-Shell Nanocrystal Photodetectors beyond 3 µm Wavelength." Advanced Functional Materials.