This PDF file contains the front matter associated with SPIE Proceedings Volume 11475, including the Title Page, Copyright information, and Table of Contents.

Organic electronic devices are maturing from the academic research into the industrial development. With the use of “electronics everywhere” on a large scale we will transform the “consumer electronics” into a “consumable electronics”. Therefore, environmentally friendly materials are important to use. New developments of bio-organic materials will be reported. Such materials can also be used to interface the biological and biomedical research with the organic electronics field. Furthermore, bio-organic systems utilizing enzymes immobilized on graphene will be discussed. Their selectivity combined with their operation at ambient conditions make such bio-nano-electro-catalytic systems highly attractive.

Cephalopods, such as squid, octopuses, and cuttlefish, have captivated the imagination of both the general public and scientists for more than a century due to their visually stunning camouflage displays, sophisticated nervous systems, and complex behavioral patterns. Given their unique capabilities and characteristics, it is not surprising that these marine invertebrates have recently emerged as exciting models for novel materials and systems. Within this context, our laboratory has developed various cephalopod-derived and cephalopod-inspired materials with unique functionalities. Our findings hold implications for next-generation adaptive camouflage devices, sensitive bioelectronic platforms, and advanced renewable energy technologies.

Cell membranes localize and orchestrate the critical cellular processes, reactions, and sensing that give rise to life. The variety of lipids and proteins comprising these biomembranes enables fine-tuned control of the biological processes happening within them. However, to discover how such a complex system of myriad components gives rise to membrane properties and functions, we reduce the system to minimal components and in a step-wise and controlled manner, increase the complexity. The interface that delivers information about the processes under study is critical. We turn to organic electronics for its known compatibility with biological materials and their sensitive and convenient read out of information. I describe the advances in building the interface between cell membranes and organic electronics as well as the types of measurements and information that can be garnered from these devices. I highlight examples in ion channel biophysics, pathogen interactions, and biosensing.

Here we report recent advances in precise engineering to incorporate advanced electrophoretic drug delivery system into implantable devices for treating neurological disorders including both depth probes and cortical arrays with recording capabilities. The efficacy of the platform is demonstrated by stopping epileptic seizures in vivo. This is the first in vivo demonstration of an electrophoretic implant treating a neurological disorder and offers a glimpse of what can be achieved by tailored engineering of electrophoretic devices. We anticipate this work to be the starting point for new stimulation, recording and drug delivery paradigms in chronic neural implantation.

Plants are the basis of food, providers of oxygens and regulators of the ecosystem. We are developing bioelectronic technologies for real time monitoring and dynamic control of plant physiology. We developed an implantable device for controlled delivery of phytohormones with high precision in dose and minimal wound response from the plant. The capillary-based organic electronic ion pump can be implanted into the leaf of intact plants and efficiently deliver ABA, one of the main hormones that mediates plant responses to stress. In addition, we are developing sugars sensors based on the organic electrochemical transistor for real time monitoring in trees. The OECTs sensors show high device to device reproducibility and stability during the operation in the in-vivo environment. The sensors reveal sugars transport kinetics that are observed for the first time. Our work sets the way to establish these devices for fundamental research but also for application in agriculture and forestry.

Metal nanostructures offer means to control light at the nanoscale via collective charge oscillations called plasmons. This resonant phenomenon is sensitive to changes in the local environment, which others and we have used extensively for biosensing applications. Plasmonic nanostructures can also be used for light-to-heat conversion at the nanoscale, enabled by non-radiative plasmon decay. I will discuss how to use such plasmonic heating in combination with organic materials for sensing applications [1,2] and present our recent research on plasmons also in organic nanostructures [3]. 1 M. Shiran Chaharsoughi, D. Tordera, A. Grimoldi, I. Engquist, M. Berggren, S. Fabiano and M.P. Jonsson, Adv. Opt. Mat. 6, 1 (2018) 2 M.S. Chaharsoughi, D. Zhao, X. Crispin, S. Fabiano and M.P. Jonsson, Adv. Fun. Mat. 29, 1 (2019) 3 S. Chen, E.S.H. Kang, M.S. Chaharsoughi, V. Stanishev, P. Kühne, H. Sun, C. Wang, M. Fahlman, S. Fabiano, V. Darakchieva and M.P. Jonsson, Nature Nano. 15, 35 (2020)

OLEDs are attractive and distinctive light sources because of they are very thin, emit over an area and can be flexible. These features also make them very interesting for medical applications as compact, lightweight sources can enable ambulatory treatment. In photodynamic therapy (PDT), light in combination with a photosensitiser leads to the generation of reactive oxygen species that can kill nearby cells. We report the development of improved OLEDs for PDT. In particular, we show their use for antimicrobial PDT i.e. for killing bacteria, parasites and fungi in vitro.

Shortwave Infrared (SWIR) light imaging is critical in a variety of applications ranging from medical diagnosis, industrial inspection and safety monitoring, etc. due to their information-rich merits. This report presents an organic up-conversion imager for SWIR light imaging. The imager integrates an organic SWIR photodiode (OPD) and an organic light emitting diode (OLED) to convert invisible SWIR image directly into visible image without sophisticated data acquisition and processing electronics. Our imager is capable of imaging light signal with wavelength up to 1400 nm, due to the sensitivity of the novel OPD. The design guidelines for attaining highly sensitive and low voltage up-conversion imagers are revealed by studying the photo responsivity and current-voltage characteristics of the SWIR PD and OLED. The results show that the elimination of deep trap states in the SWIR PD favors the photo sensitivity and reduces the operating voltage of the up-conversion imager.

I will summarize work in my team to develop photonic bioimplants for controlling and monitoring brain activity. These devices make use of our recent development of ultrathin (<20um), flexible and efficient OLEDs with advanced thin film encapsulation which can be stored and operated for several weeks while fully immersed in water. We demonstrate use of our OLEDs for photo-stimulation of neurons through optogenetics in a number of different model systems, and also show the integration of dielectric filters to realize fluorescence imaging of genetically encoded calcium indicators under excitation by our OLEDs.

Photostimulation using Au and Si-based nanomaterials has shown promise for optical stimulation of cells. However, these methods still suffer from key limitations: the need for high laser power, low thermal conversion efficiency, and unproven long-term stability. We report a breakthrough hybrid-nanomaterial for remote and non-genetic light-induced control of targeted cell activity. We combine one-dimensional (1D) nanowires (NWs) and two-dimensional (2D) graphene flakes grown out-of-plane with tailor-made physical properties for highly controlled photostimulation. Photostimulation using NW templated 3D fuzzy graphene (NT-3DFG) is flexible due to its broadband absorption and does not generate cellular stress. Our light-based platform adds a powerful toolset to the basic scientists studying cell signaling within and between tissues.

The bandgap tunability in methylammonium (MA) lead halide perovskites has motivated us to design a photoresistor array made of MAPbI₃, MAPbBr_1.5I_1.5, and MAPbBr₃. To pattern devices on the same substrate, a novel method of laser engraving the substrate was employed. In this method, first, an indium tin oxide (ITO) coated plastic substrate was laser engraved to make microchannels with a width of 50-100 µm. Capillary motion force was used to fill each channel with a different solution containing the perovskite precursors. The current-voltage characteristics of each sensor were studied under dark and light conditions. Light-emitting diodes with different wavelengths were used to study the response of each sensor to monochromic lights. The results are promising toward the fabrication of larger arrays of photosensors which potentially can be used for compact and integrated photospectrometers in lab-on-a-chip devices.

Increasing demand for low-cost devices has directed attention to developing simple methods for the deposition of solution-based semiconductors thin layers on various substrates. In recent years, 3D printing technologies have been known as a rapid, cost-effective technique for the deposition of a variety of materials. Here we employed pneumatic nozzle printing to make low-defect thin films of methylammonium lead iodide (MAPbI₃) perovskite. The process parameters were optimized to control the crystallization condition. By using top-gate bottom-contact configuration, perovskite transistor on the silicon substrate was developed. The electrical properties of the fabricated transistor were measured under ambient light.

In this talk, we will present organic photodiodes (OPDs) based on polymeric bulk heterojunctions with a level of performance that within the visible spectral range, rivals that of low-noise SiPDs in all metrics, except response time. Large-area OPDs on rigid and flexible substrates retain an unprecedented level of performance. Advantages of OPDs are further illustrated and quantified in a biometric monitoring application that uses ring-shaped, large-area, flexible OPDs, while maintaining low-noise SiPD-level performance. We will discuss how this remarkable performance arises from the selection of photoactive layer materials and by device-geometry optimization without charge-blocking layers.

2D networks of interconnected nano-objets (nanowires, nanoparticles, molecules) are experimentally and theoretically explored to implement unconventional computing machines, and especially reservoir computing. We discuss several key features of 2D networks of molecularly functionalized nanoparticles (called NMN : nanoparticle molecule network) to assess their possible use for reservoir computing: highly non-linear electron transport, variability, complex/rich dynamics (harmonic, interharmonic, intermodulation distortions), co-tunneling, noise and plasmonic response. We discuss the electron transport properties of some molecules of interest for chemical and biochemical sensing with these NMNs reservoir computing approaches, combining sensing and computing in a single nanoscale device.

Organic field-effect transistors (OFETs) are highly promising candidates for chemical and biological sensing applications. Many organic semiconductor compounds are solution-processable at low temperatures on a variety of substrates, which allows for cost-effective fabrication methods, leading to smart (disposable) sensor tags in the field of health-, food- and environmental monitoring. Concerning the detection of ions or biological molecules in aqueous solutions, a water-stable operation of OFET sensor elements is crucial. Thus low voltage operation is a prerequisite. In this context electrolyte-gated OFETs (EGOFETs) seem to be the transducing devices of choice. Yet, many EGOFETs suffer from bias stress induced degradation of the organic semiconductor. In this contribution we will therefore benchmark EGOFETs as the transducing devices against other state of the art devices such as classical CMOS FETs implemented in an electrolyte-gated sensor configuration.

Field-Effect Transistors (FETs) are the key building blocks in a wide range of electronic applications such as sensors and electrical switches. The emergence of Organic Field-Effect Transistors (OFETs) unveiled special features, which have taken the application of FETs into uncharted territories. These unique features include but are not limited to, low- cost processing, lightweight, mechanical flexibility, biocompatibility, broad material availability, etc. Similar to their inorganic counterparts, doping organic semiconductors (OSC) can significantly alter or improve their electrical and optoelectronic properties, resulting in doping induced OFET multi-functionalities. In this study, the impact of multi-doping on the OFET device performance and functionalities has been systematically investigated and evaluated under varying conditions of light, heat, and gate voltages. The experimental results appear to support the proposed hypothesis behind the multi-functionality of the system under study. The present work will provide valuable scientific insights for the advancement of OFET based sensors, switches, and modulators.

The development of solid-state radiation dosimeters has been crucial in allowing human workers to thrive while using tools that output ionizing radiation. Here, we report on solid-state tissue-equivalent radiation dosimeters based on PEDOT:PSS. We show reliable measurements of the radiation dosimeters subjected to a wide range of exposure energies and footprints of both X-ray and gamma. In addition, there is a strong indication that the PEDOT:PSS-based devices also give response when introduced to neutron sources. This represents a significant step forward in the production of cheap, reusable radiation dosimeters made with materials of similar radiation cross-section to the human body.

Hygroscopic insulator field effect transistors (HIFETs) are a unique class of OTFTs with low-voltage operation and a simple, solution processable, and solid-state structure. Sensitivity to various analytes can be achieved by modification of the gate electrode, but device performance is often degraded by the change in electrical characteristics. We have studied the effect of gate conductance on HIFET performance. As gate conductance increases, key figures of merit improve until plateauing. We propose this is due to the dependence of the effective gate voltage on its resistance when a leakage current is present. These results are widely applicable for device optimisation.

Red light detection is vital for numerous applications, including full-color imaging, optical communication, machine vision, etc. However, this development is hindered by a limited choice of small bandgap and narrow bandwidth materials. To solve this problem, the promising strategy of charge collection narrowing has been devised which requires a relatively thick active layer, usually beyond 1.5 μm, to suppress surface-generated carriers thus ensuring the purity of red-light response spectrum, while restricting device frequency bandwidth and introducing extra uncertainties with high throughput deposition methods. Therefore, the realization of thin-film, red-light OPDs would dramatically enhance its potential utility and extend the available range of suitable organic semiconductors. In this work, the selective exciton activation mechanism is applied to a simple planar heterojunction architecture, which enables only specific excitons separated into free charge carriers, while all other excitons are quenched before reaching the donor/acceptor interface. Such a mechanism makes the design of red-light detectivity spectrum even with a considerably thin active layer feasible. By adjusting the ratio of PTB7 in P3HT, an obvious increase of photoresponse is obtained with a peak shift from 645 nm to 745 nm. Moreover, the 90 wt.% PTB7 addition gives high photoresponsivity at 745 nm simultaneously keeping a narrow full-width at-half-maximum of ~50 nm. Highly competitive performance in terms of specific detectivity and linear dynamic range is demonstrated. Therefore, this design concept is intriguing for tunable thin-film filter-less red-light organic photodiodes and also applicable to other spectral windows in the near future.

Colorimetric sensors are ubiquitous tools that are deployed in various research, academic and on-field diagnostic settings. High accuracy and quick readout capability of these sensors are key for biochemical sensing and medical diagnostics. In this article, we introduce ColorX, a novel colorimetric sensor built by modifying a genetic commercially available fitness tracker. The inbuilt components of a fitness tracker such as a heart-rate sensor, LEDs, photodiodes, transimpedance amplifiers provide a compact and portable form factor. ColorX leverages the bluetooth from the fitness tracker for wireless data transmission to smart phones. As a device validation strategy, ColorX was validated by measuring Nitrates in water. In all our experiments ColorX matched the technical performance of a standard benchspectrophotometer. ColorX was able to achieve excellent sensitivity in measuring nitrates as low as 10mg/ml.

We study the processes of interaction between molecules and H-aggregates of a dye adsorbed at the surface of AgBr and AgBrI emulsion microcrystals (EMC). Methods of the low-temperature (T = 4.2 K) luminescence enable to associate the “self-desensitization” with the mechanism conditioned by the interaction of Н- and J-aggregates of the dye with its molecules, which results in the decay of the spectral sensitivity of emulsions employing organic dyes. Methods of low temperature (T = 77 K) luminescence show the interaction of the first excited state of the Н-aggregates with the triplet state of the molecular dye, which indicates the process of the excited Н-aggregates’ energy dissipation through the triplet state of its molecules.