2025-07-28 ノースカロライナ州立大学（NCState）
Photo credit: Brendan O’Connor.
＜関連情報＞
- https://news.ncsu.edu/2025/07/tiny-spectrometer/
- https://www.sciencedirect.com/science/article/pii/S2666998625001796?via%3Dihub
バイアス調整可能なタンデム有機光検出器に基づく単一ピクセル分光計 Single-pixel spectrometer based on a bias-tunable tandem organic photodetector
Harry M. Schrickx, Abdullah Al Shafe, Caleb Moore, Yusen Pei, Franky So, Michael Kudenov, Brendan T. O’Connor
Device Available online: 22 July 2025
DOI:https://doi.org/10.1016/j.device.2025.100866
Highlights
- Single-pixel spectrometer accurately reconstructs narrow and broad light spectra
- Tandem OPD design enables bias-tunable spectral sensing from 400 to 1,000 nm
- Two-terminal architecture simplifies integration and supports low-power operation
- Fast response and high detectivity support sensitive low-light measurements
The bigger picture
An ultraviolet (UV)-visible spectrometer is typically a benchtop instrument that measures the intensity of light as a function of wavelength to analyze the optical properties of a sample. These tools are widely used in applications such as chemical analysis, environmental monitoring, medical diagnostics, and quality control in manufacturing. Miniaturization enables new applications in portable diagnostics, wearable sensors, real-time in-field analysis, and integration into consumer devices. However, most miniaturized spectrometers face trade-offs in spectral resolution, bandwidth, and complexity, often relying on filters, gratings, or moving parts that limit imaging capability. This work introduces a single-pixel reconstruction spectrometer through a compact tandem photodiode design. Spectral reconstruction is achieved through voltage-dependent responsivity that removes the need for external optical components while achieving broad spectral bandwidth, high detectivity, and fast operating speeds.
Summary
Miniaturized computational spectrometers enable compact, lightweight sensing using a modulated spectral response and reconstruction algorithm. We present an organic photodetector (OPD)-based spectrometer that leverages complementary spectral responses of target organic semiconductors (D18-Cl, L8BO, PTB7-Th, and COTIC-4F) in a tandem cell design. The sub-cells have opposing polarity, causing a bias-tunable spectral response, resulting in a spectrometer sensitive to wavelengths ranging from ultraviolet to near infrared (400–1,000 nm). Through sweeping external bias, the photoresponse enables the reproduction of both narrow and broad-spectrum incident light. The detector demonstrates responsivity of 0.27 A W−1, detectivity of 1.4 × 1012 Jones, and a rise/fall time of 2.82/3.72 μs while operating at voltages of less than 1 V. The tandem OPD-spectrometer design realizes high-performance imaging spectrometers without the need for external gratings or filters, with applications in portable and integrated micro-spectrometers.
