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Electrically Coded Retinomorphic Spectrophotodetector
Mohit Kumar1,2, Hyunmin Dang2, Hyungtak Seo1,2
1Department of Energy Systems Research, Ajou University, Suwon, Republic of Korea.
Advanced Materials (Deerfield Beach, Fla.)
|July 17, 2026
Summary
A new self-powered pyro-photodetector directly encodes light wavelength into electrical signals. This machine learning-free device enables fast, accurate color sensing for various applications without complex processing.
Area of Science:
- Materials Science
- Optoelectronics
- Sensor Technology
Background:
- Accurate color sensing is crucial for diverse applications but limited by bulky optics and complex processing.
- Existing compact systems struggle with direct, device-level color classification.
- Need for energy-efficient, high-precision spectral sensing solutions.
Purpose of the Study:
- To demonstrate a machine learning-free, self-powered retinomorphic pyro-photodetector for direct electrical wavelength encoding.
- To enable in-sensor spectral discrimination without computational post-processing.
- To establish a portable platform for real-time, energy-efficient spectral sensing.
Main Methods:
- Development of a multiterminal Ag/ZnO/n-Si/Ag pyro-photodetector device.
- Utilizing electrostatically balanced built-in potentials for wavelength-to-current conversion.
- Demonstrating direct electrical wavelength encoding from 365 to 940 nm.
Main Results:
- The device achieved wavelength decoding with sub-3 nm accuracy and a pyroelectric current rise-time of ~46 µs.
- Enabled end-to-end wavelength classification with 300 ms latency, reducing computational complexity.
- Demonstrated high accuracy (>92%) in plant health, pigment sensing, and quantifying water adulteration in food products.
Conclusions:
- The retinomorphic pyro-photodetector offers a portable platform for real-time, energy-efficient, high-precision spectral sensing.
- Direct in-sensor color recognition and wavelength classification are achieved without external neural processing.
- This technology provides a general route toward advanced spectral sensing applications.
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