Optical-based stretchable multimodal sensors for detecting strain and light with periodic buckling structures

Area of Science:

• Materials Science
• Biomedical Engineering
• Optoelectronics

Background:

• Stretchable optoelectronic sensors are crucial for wearable health monitoring.
• A key challenge is the shift in light-detection location upon device deformation, hindering accurate physiological signal interpretation.

Purpose of the Study:

• To develop a stretchable photodetector capable of dual optical and strain sensing.
• To enable real-time estimation of the shifting light-detection position in wearable devices.

Main Methods:

• Designed a periodic-buckling stretchable organic photodetector (OPD).
• Utilized open-circuit voltage (Voc) for light intensity sensing and short-circuit current (Isc) for combined light intensity and active area variation sensing.
• Evaluated device performance under strain up to 60%.

Main Results:

• The OPD demonstrated stable performance with <1.1% variation in Voc under 60% strain.
• Short-circuit current (Isc) changes allowed for geometric localization of the photodetection site.
• A strain gauge factor of 0.44 was derived from Isc measurements.

Conclusions:

• The developed OPD addresses the critical limitation of location shifting in stretchable photodetectors.
• This technology offers a pathway toward high-resolution, position-aware wearable optical biosensing.