Filter-free integrated sensor array based on luminescence and absorbance measurements using ring-shaped organic...

Area of Science:

• Optoelectronics
• Chemical Sensing
• Materials Science

Background:

• Traditional optical sensors often require complex readout systems and optical filters.
• Integrating photo-detectors directly onto the sensor platform can simplify device architecture.
• Discriminating between excitation light and sensing signals is crucial for accurate optical measurements.

Purpose of the Study:

• To develop a simplified optical waveguiding sensor array with integrated organic photodiodes.
• To demonstrate a versatile platform capable of both luminescence and absorption measurements.
• To validate the sensor's applicability for detecting various analytes in different phases.

Main Methods:

• Monolithic integration of organic photodiodes using layer-by-layer vacuum deposition.
• Utilizing screen-printing techniques for sensing and waveguide layers, including in- and out-coupling elements.
• Fabrication on glass or polymer foil substrates.

Main Results:

• A sensor array design that eliminates the need for optical filters by discriminating excitation light and sensing signals.
• Demonstrated near-zero background light interference.
• Successful detection of relative humidity, oxygen, and carbon dioxide in gas phase via luminescence.
• Detection of oxygen and pH in aqueous media.
• Measurement of oxygen and carbon dioxide in gas phase via absorbance.

Conclusions:

• The integrated optical waveguiding sensor array offers a simplified, versatile, and robust platform for chemical sensing.
• The screen-printing and vacuum deposition methods enable cost-effective fabrication.
• Consistent calibration characteristics across multiple sensor chips confirm reliability and reproducibility.