Semiconducting nanocrystals, recognized by the 2023 Nobel Prize in Chemistry, are versatile materials created solely through chemical synthesis, now integral to functional nanotechnologies. Recent research integrates AI technologies into nanocrystal development using robotic tools to enhance data size and accelerate innovation. Addressing challenges like generating white light from a single material, recent studies focus on two-dimensional structures that spontaneously intercalate organic and inorganic components. While prior investigations mainly used random selection, our experimental approach is based on molecular descriptors of organic cations to study their role in emission characteristics. To this aim, we collected experimental data in real time and uploaded it to a digital platform for data interaction, analysis, and preservation. We first carefully selected primary and secondary amines and established a robust synthetic protocol that is performed at relatively low temperatures and through simple steps. To date, we have prepared more than 50 different layered structures and established seven digital protocols, enabling direct linkage between structural and optical features. Initial correlations indicate that using short organic cations with heteroatoms promotes the synthesis of broadband-emitting layered structures, and changes in the heteroatom position might lead to tunable emission color from blue to white. Such real-time data integration and analysis, which includes sorting, interactive exploration, and data graphical representation, offer new pathways for developing efficient white-emitting structures from a single material, with a broad perspective for other functionalities.

The development of medical devices that comply with the soft mechanics of biological systems at different length and complexity levels is highly desirable. With the emergence of conducting polymers exciting directions opened up in bioelectronics research, bridging the gap between traditional electronics and biology. With the ultimate goal of fully integrated devices, organic bioelectronic technologies have been heavily explored the past decade resulting in novel materials/device configurations. Multiplexing capability, ability to adopt to complex performance requirements in biological fluids, sensitivity, stability, literal flexibility and compatibility with large-area processes are only some of the merits of this technology for biomedical applications. A recent example of a bio-integrated electronic device, the BiOET, is based on polymeric semiconductor technology and is fabricated using nano/micro-fabrication methods in conjunction with synthetic biology approaches to incorporate hierarchically organized biological models of the cell membrane. Despite their significance, cell membranes are still an underexplored target for studying the mechanisms of diseases or drug therapies. Cell-free commercially available technologies for cell membrane studies have been limited to synthetic membranes that lack the inherent complexity found in the membrane of the cell. In this talk I will describe a method to create native cell membranes, using vesicles derived from live cells, on top of conducting polymer- based microfabricated electrodes and transistors. The activity of transmembrane proteins in response to different stimuli can be electrically monitored, offering a direct means to characterize drug toxicity or potency at the critical first contact point: membrane interaction.

The rapid evolution of bioelectronics has opened new directions in tissue engineering, driving major advancements in the biomedical sector. This talk will present the transformative potential of organic bioelectronics, highlighting their role in interfacing seamlessly with biological tissues to enable real-time monitoring, diagnostics, and therapeutic interventions. Our recent developments for in vitro bioelectronics will be demonstrated, emphasizing the integration of biomimetic materials and innovative design approaches that ensure functionality and longevity within the biological environment. Additionally, this talk will extend to energy harvesting devices, namely triboelectric nanogenerators (TENGs). TENGs have emerged as revolutionary sustainable devices, particularly in the fields of bioelectronics and wearable electronics. By harnessing the triboelectric effect, TENGs convert mechanical energy from body movements or environmental sources into electrical energy, offering green energy alternatives and sensing capabilities. Our research introduces new design approaches to enhance the performance and flexibility of TENGs by incorporating bio-derived materials and nanocoatings through chemical synthesis and surface engineering. Our findings demonstrate that these devices can operate efficiently under various conditions, making them highly adaptable for diverse applications. By advancing the design and functionality of TENGs, our research contributes to developing next-generation, eco-friendly energy solutions, addressing the critical need for sustainable technology in our society.

Developments in the telecommunication systems are significantly relying on electronic components capable to address functionalities related to the corresponding signals. Radio Frequency Micro-Electro-Mechanical Systems (RF MEMS) were introduced more than two decades ago and due to their exceptional ensemble of properties immediately attracted significant attention across the RF community. Nowadays, owing to their unique ability to satisfy the needs of the emerging RF technologies (such as of the 5G), a novel perspective has been offered for RF MEMS and this revived the research attention around the field. Current topics of interest include RF applications operating under high RF-power levels and/or at the higher micro- or at the millimeter wave frequency bands.

This talk will present the operation principles of RF MEMS capacitive switches and a summary of the related research developments over the recent years at MRG-IESL-FORTH group with emphasis given on implementations related to high power applications.

Semiconductor nanoparticles, also known as quantum dots, given their robust photoluminescent properties, single source excitation and multicolor emission properties have been employed for multiplexing and long-term imaging studies. [1] Cation exchange (CE) reactions on nanocrystals consists of the replacement of cations in the nanocrystalline structure with different metal ions while maintaining in place the anion framework. This technique has been extensively used for the synthesis of nanocrystals at different compositions. Here, we exploit CE reactions to radiolabel cadmium-free semiconductor NCs of ZnS, ZnSe and chalcopyrite (CuFeS₂) NCs with Cu-64 radioisotope. [2] To make it possible, a one-step CE protocol that is straightforward and highly efficient while maintaining good NC colloidal stability, the type of ligand coating to be chosen as water soluble stabilizer agents and the amount of Copper-64 to be exchanged were the key factors. This enabled to obtaining ⁶⁴Cu:CuFeS₂ in very high yields which did not require any further work out for the purification thus speeding up the radiolabeled NCs preparation. This unique approach of CE reaction enables to tune the specific activity in a wide range (from 2 to 100 TBq/g) with an unprecedentedly record value of specific activity up to 100 TBq/g. In addition, among the NCs explored, CuFeS₂ NCs even after partial-CE reaction with Copper-64 were promising heat mediators for photo-thermal therapy (PPT). The synergic toxicity of photo-ablation and ⁶⁴Cu mediated radiotherapy ionization is here used to eliminate the glioblastoma and epidermoid carcinoma tumor cells. A modified version of this protocol was also established to obtain copper-64 radio-clusters of sub nanometer size and having also radio and photoluminescent properties. The optical stability of the copper cluster was tuned by controlling the size, coating and composition and will be also discussed. Throughout this presentation, for the best performing materials preclinical results aimed at evaluating their therapeutic efficacy and bio-distribution will be also discussed.

References

[1] WJ Parak, et al., Nanotechnology, 2003, 14 (7), R15

[2] Avellini, T. et al, Adv. Funct. Mat. 2020, 30, 2002362

Photonic Time-Crystals (PTCs) are media whose electromagnetic properties are modulated periodically in time. When the modulation period is comparable to a single cycle of the wave propagating within them and the modulation amplitude is large, the dispersion relation in PTCs exhibits momentum bands separated by significant momentum gaps. The momentum gaps are especially interesting – as they give rise to exponential amplification, extracting energy from the modulation. This talk will review the EM concepts of PTCs, and will focus on light-matter interactions and especially on light emission and nonlinear frequency conversion in PTCs. The last part of the talk will describe recent experimental progress on observing time-refraction within a single optical cycle.

Acknowledgements:  European Research Council (ERC-Consolidator) under grant agreement No. 101045135 (Beyond Anderson).