Organic Photodetectors and Their Applications in Imaging Systems

Organic photodetectors (OPDs) are light‐sensitive devices fabricated from carbon‐based semiconductors that offer unique advantages in flexibility, spectral tunability and low‐cost processing. Their operation relies on efficient absorption of photons, exciton generation and dissociation at donor–acceptor interfaces, followed by charge collection at electrodes. OPDs have rapidly progressed to rival inorganic counterparts in key performance metrics such as specific detectivity, response speed and dark‐current suppression. They enable conformable, large‐area and even visibly transparent imagers, finding applications in biomedical diagnostics, wearable health monitors, gesture‐controlled interfaces and integrated optical sensors. Advances in device architecture, materials design and noise‐management strategies continue to expand their spectral coverage from ultraviolet to near‐infrared, while emerging narrowband and self‐filtering designs promise miniaturised spectroscopic capabilities. Such developments underline the global significance of OPDs for next‐generation imaging and sensing systems.

Research from Nature Portfolio

Recent studies have demonstrated a transparent near‐infrared imaging array integrated onto commercial displays, employing patterned organic photodetector subpixels and conductive copper grids to achieve over 10¹² Jones detectivity at 850 nm alongside 70 % visible transmittance. Electro‐optical modelling guided the optimisation of pixel geometry and electrode design, enabling touchless and gesture‐controlled interfaces without obstructing the display image. Parallel work has elucidated the fundamental origins of dark current in OPDs, revealing that mid‐gap trap states dominate leakage under reverse bias. Temperature‐dependent quantum‐efficiency measurements have been used to quantify trap densities, from which intrinsic limits on specific detectivity were derived, offering material and device design guidelines to minimise noise.

Organic Photodetectors and Their Applications in Imaging Systems publication trend

The graph below shows the total number of articles in organic photodetectors and their applications in imaging systems across all publications each year (not limited to Nature Index journals).

Technical terms

Organic photodetector (OPD): A light‐sensitive device using carbon‐based semiconductors to convert photons into electrical current.

Dark current: The unwanted current that flows through a photodetector in the absence of illumination, contributing to noise.

Specific detectivity (D*): A figure of merit quantifying the sensitivity of a detector, normalized to bandwidth and active area, with higher values indicating better performance.

External quantum efficiency (EQE): The ratio of collected charge carriers to incident photons at a given wavelength.

Bulk heterojunction: A blend of donor and acceptor materials forming an interpenetrating network that aids exciton dissociation.

Charge‐transfer state: An intermediate electronic state formed at the donor–acceptor interface, crucial for exciton separation and photocurrent generation.

References

1. A touchless user interface based on a near-infrared-sensitive transparent optical imager. Nature Electronics (2023).
2. Mid-gap trap state-mediated dark current in organic photodiodes. Nature Photonics (2023).
3. Vacuum‐free lamination via controlled polymer adhesion for selective photogeneration and photodetection. Carbon Energy (2024).
4. Recent Progress in Organic Photodetectors and their Applications. Advanced Science (2020).
5. Intrinsic Detectivity Limits of Organic Near‐Infrared Photodetectors. Advanced Materials (2020).
6. Narrowband organic photodetectors – towards miniaturized, spectroscopic sensing. Materials Horizons (2022).