Organic Phototransistor and Photodetector Technologies

Organic phototransistors and photodetectors are optoelectronic devices that convert incident light into electrical signals by leveraging the tunable electronic properties of conjugated polymers and small‐molecule semiconductors. Their solution processability and mechanical flexibility enable low-cost fabrication on large‐area substrates, while molecular engineering affords control over absorption spectra, charge carrier mobility and interfacial charge separation. Architectures such as bulk heterojunctions, supramolecular assemblies and multi-electrode transistors address key challenges in exciton dissociation, dark current suppression and dynamic range. Performance metrics—including photoresponsivity, specific detectivity and on/off ratio—have been boosted by innovations in material design and device structure. These technologies have found application in near-infrared imaging, real-time radiation dosimetry, wearable sensors and integrated photonic circuits, reflecting their broad significance in healthcare, environmental monitoring and flexible electronics.

Research from Nature Portfolio

Recent studies have demonstrated band-like charge transport in vacuum-deposited small-molecule thin films, yielding organic phototransistor arrays with ultralow dark currents and unprecedented detectivity exceeding 10^17 cm Hz^1/2 W^−1. This breakthrough combines high carrier mobility with excellent optical figures of merit, pointing towards high-speed, low-noise applications. Another key advance introduces a dual-gate phototransistor concept that merges photodiode and phototransistor functions, achieving both high photoconductive gain and linear photoresponse without external circuitry. Device prototypes, configured as large-area imaging arrays, exhibit tunable dynamic range and reduced electrical noise. More recently, supramolecular nanowire networks within a vertical phototransistor architecture have been shown to trigger exceptional near-infrared sensitivity using a wide bandgap active material. By combining ad-hoc self-assembly with innovative electrode scaffolds, these devices deliver photoresponsivities up to 2 × 10^5 A W^−1 in the visible range and maintain strong performance at 940 nm, opening new avenues for health-monitoring photoplethysmography.

Organic Phototransistor and Photodetector Technologies publication trend

The graph below shows the total number of articles in organic phototransistor and photodetector technologies across all publications each year (not limited to Nature Index journals).

Technical terms

Organic phototransistor: A three-electrode device in which an organic semiconductor layer modulates channel current under illumination, providing internal amplification of photoinduced charges.

Photoresponsivity: The ratio of photocurrent generated to incident optical power, measured in amperes per watt (A W^−1), indicating the efficiency of light-to-electrical conversion.

Specific detectivity (D*): A figure of merit expressing the minimum detectable signal relative to noise, given in Jones (cm Hz^1/2 W^−1), reflecting sensitivity under low-light conditions.

Ambipolar transport: Balanced conduction of both electrons and holes within a semiconductor, enabling symmetric photoresponse modes.

Bulk heterojunction: An interpenetrating network of electron-donor and electron-acceptor materials that enhances exciton dissociation and charge transport in photodetectors.

References

1. Band-like transport in small-molecule thin films toward high mobility and ultrahigh detectivity phototransistor arrays. Nature Communications (2019).
2. Dual-gate organic phototransistor with high-gain and linear photoresponse. Nature Communications (2018).
3. Supramolecular engineering of charge transfer in wide bandgap organic semiconductors with enhanced visible-to-NIR photoresponse. Nature Communications (2021).
4. Conjugated Polymer Heteroatom Engineering Enables High Detectivity Symmetric Ambipolar Phototransistors. Advanced Materials (2024).
5. Flexible fully organic indirect detector for megaelectronvolts proton beams. npj Flexible Electronics (2023).
6. Large-scale roll-to-roll printed, flexible and stable organic bulk heterojunction photodetector. npj Flexible Electronics (2018).