KIMS Develops Flexible NIR Photodetector That Withstands 4,000 Bends

Researchers at the Korea Institute of Materials Science (KIMS) have developed a flexible near-infrared (NIR) photodetector capable of maintaining high sensitivity even after thousands of bending cycles. The breakthrough addresses a critical challenge in flexible electronics: preserving signal integrity and detection efficiency when devices are subjected to repeated physical deformation.

The device utilizes a heterojunction composed of tellurium (Te) and n-type hydrogenated amorphous silicon (n-a-Si). To maximize performance, the KIMS team implemented systematic phosphorus doping and engineered the internal electric-field structure, which included the addition of a front-surface-field layer. According to the research, these optimizations resulted in a 5.1-fold increase in photoresponsivity and a 2.6-fold increase in detectivity when compared to conventional detector structures.

The Challenge of Flexibility

Traditional high-sensitivity photodetectors often rely on rigid crystalline structures that are prone to cracking or performance degradation when bent. Near-infrared detection is particularly vital for applications ranging from medical imaging to autonomous vehicle sensors, where sensors must often be integrated into curved surfaces or wearable tech. By using amorphous silicon and tellurium, the KIMS team created a material interface that is inherently more resilient to mechanical strain than traditional semiconductors.

Impact on Sensor Durability

The most significant finding regarding the device's durability is its ability to withstand repeated stress without losing functionality. The team found that the photodetector retained more than 90% of its initial photoresponsivity after 4,000 bending cycles. This level of stability suggests that the phosphorus-driven structural engineering effectively prevents the formation of defects that typically plague flexible NIR sensors, ensuring that the device remains reliable over a long operational lifespan.

Future Applications

This research, published July 6, 2026, in the journal Advanced Science under the title "Systematic Phosphorus-Driven Structural and Field Engineering of n-a-Si for Flexible n-a-Si/Te Near-Infrared Photodetectors," provides a blueprint for the next generation of flexible photonic devices. The ability to combine high detectivity with extreme mechanical flexibility opens the door for more advanced wearable health monitors and flexible communication systems. Future development will likely focus on scaling the manufacturing process and testing the device in real-world environmental conditions.