How to Achieve High Spatial Resolution in Organic Optobioelectronic Devices?

Fabbri, Luca; Migliaccio, Ludovico; Širvinskyt, Aleksandra; Rizzi, Giacomo; Bondi, Luca; Tamarozzi, Cristiano; Weber, Stefan A.L.; Fraboni, Beatrice; Glowacki, Eric Daniel; Cramer, Tobias

How to Achieve High Spatial Resolution in Organic Optobioelectronic Devices?

Files

2025Fabbri.pdf(3.42 MB)

Date

2025-05-01

Authors

Fabbri, Luca

Migliaccio, Ludovico

Širvinskyt, Aleksandra

Rizzi, Giacomo

Bondi, Luca

Tamarozzi, Cristiano

Weber, Stefan A.L.

Fraboni, Beatrice

Glowacki, Eric Daniel

Cramer, Tobias

ORCID

0000-0002-0280-8017

Publisher

WILEY

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Abstract

Light activated local stimulation and sensing of biological cells hold great promise for minimally invasive bioelectronic interfaces. Organic semiconductors are particularly appealing for these applications due to their optoelectronic properties and biocompatibility. This study examines the material properties necessary to localize the optical excitation and achieve optoelectronic transduction with high spatial resolution. Using photovoltage and photocurrent microscopy, we investigate spatial broadening of local optical excitation in Phthalocyanine/3,4,9,10-Perylenetetracarboxylic diimide (H2PC/PTCDI) planar heterojunctions. Our measurements reveal that resolution losses are tied to the effective diffusion length of charge carriers at the heterojunction. For the H2PC/PTCDI heterojunction, the diffusion length is determined to be lambda d = 1.5 +/- 0.1 mu m, attributed to reduced carrier mobility. Covering the heterojunction with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) improves the charge generation performance but increases the carrier diffusion length to lambda d = 7.0 +/- 0.3 mu m due to longer lifetime and higher carrier mobility. These findings elucidate the physical mechanisms underlying transduction and provide design principles for organic semiconductor devices aimed at achieving high efficiency and high spatial resolution for wireless and optically activated bioelectronics.

Keywords

optobioelectronics, organic heterojunctions, photocapacitors, photocurrent microscopy, photovoltage, spatial resolution

Citation

Advanced Materials Interfaces. 2025, vol. 12, issue 9, p. 1-9.
https://advanced.onlinelibrary.wiley.com/doi/10.1002/admi.202400822

Document type

Peer-reviewed

Document version

Published version

Language of document

en

Document licence

Creative Commons Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/