Seminario Organic optoelectronic smart-integrated and multifunctional devices for optical biosensing and brain-inspired computing

Organic electronic and optoelectronic devices might enable the definition of new miniaturized detection schemes to boost the advent of compact sensors for on-site analysis, given their inherent structural versatility and capability of smart monolithic integration in nm-thick multi-stack devices on almost any surface [1]. When combined with neuromorphic computing, organic devices could represent the next generation of bioelectronics. Ranging from point-of-care systems and biosensing to implants and prosthesis, organic devices could be capable of sensing, computing, and regulating in situ in a biologically relevant way.

However, challenges such as monolithic integration, fabrication scaling, and long-term stability must be addressed before the development of these closed-loop and self-adapting systems. Moreover, the physical separation of sensors and processors in conventional architectures leads to an inherent bottleneck when moving data.

In the first part of this talk, we report the integration of organic light-sources and -detectors (such as light-emitting diodes and transistors, and organic photodiodes) into ultra-compact systems for plasmonic- and fluorescence-based detection without the implementation of bulky optical components. Suitable nanostructured bidimensional plasmonic photonic components (such as nanoplasmonic grating and Distributed Bragg Reflector, respectively) are implemented for enabling and improving the sensing capabilities [2]. The components and the layout of integration were suitably designed to make the elements work cooperatively in a reflection-mode configuration [3]. We demonstrated remarkably low sensor size as low (0.1 cm3) regardless the optical detection modality, while providing (i) a quantitative and linear response that reaches a limit of detection of 10−4 refractive index units for surface-plasmon resonance (SPR) [4] and (ii) significant increase of the signal-to-noise ratio allows for halving the detection limit to 9.2 μM for a relevant fluorescent-dye detection [5].

In the second part of the talk, we report the engineering of all solution-processed organic phototransistor that

works as a multiple-stimuli synaptic device. The device implements a persistent organic radical capable of multiple wavelength photoexcitation in the photoactive layer and a ferroelectric polymer as the dielectric layer that exhibits electrically induced polarization. Persistent organic radicals exhibit a unique electronic structure characterized by a singly occupied molecular orbital, endowing them with inherent multifunctionality for light emission, light sensing, and information storage [6,7].

Theoretical calculations demonstrated that long-term memory is enabled by the photogeneration of specific trap states in the radical component of the photoactive layer, thus clearly correlating the molecular electronic configuration and neuromorphic properties in such prototypal organic compounds. We exploit the intrinsic multifunctionality of the radical-based organic phototransistor for emulating dendrite integration which is a neuromorphic feature fundamental to perform spatiotemporal pattern discrimination and network-level computation (i.e. for artificial retina applications) [8].

Such multifunctional and multi-stimuli organic devices are expected to be unique components for in-memory computation in sensor-rich systems such artificial vision, wearable electronics and miniaturized biodiagnostics.

[1] M. Prosa et al. Nanomaterials 2020, 10, 480.

[2] E. Benvenuti et al. Org. El. 2024, 128, 107023.

[3] M. Prosa et al. Adv. Funct. Mater. 2021, 31, 2104927.

[4] M. Bolognesi et al. Adv. Mater. 2023 2208719.

[5] E. Benvenuti et al. J. Mater. Chem. C 2024,12, 4243.

[6] G. Baroni et al., ACS Applied Electronic Materials, 7, 3694–3703 (2025).

[7] F. Reginato et al., Advanced Functional Materials, 35, 2411845 (2025).

[8] G. Baroni et al., Materials Horizons, DOI: 10.1039/d5mh01710f (2026)