Michele Muccini

Solution‐processed organic and hybrid semiconductor materials have great potential for ionizing radiation direct detection, as they combine high sensitivity, low‐power consumption, and flexibility. There is, however, an open challenge related to the stability in ambient/operational conditions of this class of devices. In this work, an air‐stable, solution‐processed and flexible X‐ray detector is reported, based on the integration of hybrid perovskite and organic thin films used as active layer and functional interlayers, respectively. The diode architecture and the engineering of the interface between the hybrid perovskite and the organic hole transporting material (solvent‐modified poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate) is the key to achieve enhanced detector's air stability and performance. The unencapsulated flexible device, measured in air and in passive operation (0 V), shows a limit‐of‐detection of 0.37 ± 0.04 µGy s⁻¹ and a sensitivity as high as 5.2 µC Gy⁻¹ cm⁻², which is retained within 25% after 42 days exposure to ambient conditions.

Astrocytes are responsible for maintaining homoeostasis and cognitive functions through calcium signalling, a process that is altered in brain diseases. Current bioelectronic tools are designed to study neurons and are not suitable for controlling calcium signals in astrocytes. Here, we show that electrical stimulation of astrocytes using electrodes coated with graphene oxide and reduced graphene oxide induces respectively a slow response to calcium, mediated by external calcium influx, and a sharp one, exclusively due to calcium release from intracellular stores. Our results suggest that the different conductivities of the substrate influence the electric field at the cell–electrolyte or cell–material interfaces, favouring different signalling events in vitro and ex vivo. Patch-clamp, voltage-sensitive dye and calcium imaging data support the proposed model. In summary, we provide evidence of a simple tool to selectively control distinct calcium signals in brain astrocytes for straightforward investigations in neuroscience and bioelectronic medicine.

Organic light-emitting transistors(OLETs) are multifunctionaloptoelectronic devices that combine in a single structure the advantagesof organic light-emitting diodes (OLEDs) and organic field-effecttransistors (OFETs). However, low charge mobility and high thresholdvoltage are critical hurdles to practical OLET implementation. Thiswork reports on the improvements obtained by using polyurethane filmsas a dielectric layer material in place of the standard poly(methylmethacrylate) (PMMA) in OLET devices. It was found that polyurethanedrastically reduces the number of traps in the device, thereby improvingelectrical and optoelectronic device parameters. In addition, a modelwas developed to rationalize an anomalous behavior at the pinch-offvoltage. Our findings represent a step forward to overcome the limitingfactors of OLETs that prevent their use in commercial electronicsby providing a simple route for low-bias device operation.

Among the plethora of soluble and easy processable organic semiconductors, 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-P5) is one of the most promising materials for next-generation flexible electronics. However, based on the information reported in the literature, it is difficult to exploit in field-effect transistors the high-performance characteristics of this material. This article correlates the HMDS functionalization of the silicon substrate with the electrical characteristics of TIPS-P5-based bottom gate organic field-effect transistors (OFETs) and electrolyte-gated organic field-effect transistors (EGOFETs) fabricated over the same platform. TIPS-P5 transistors with a double-gate architecture were fabricated by simple drop-casting on Si/SiO₂ substrates, and the substrates were either functionalized with hexamethyldisilazane (HMDS) or left untreated. The same devices were characterized both as standard bottom-gate transistors and as (top-gate) electrolyte-gated transistors, and the results with and without HMDS treatment were compared. It is shown that the functionalization of the silicon substrate negatively influences EGOFETs performance, while it is beneficial for bottom-gate OFETs. Different device architectures (e.g., bottom-gate vs. top-gate) require specific evaluation of the fabrication protocols starting from the effect of the HMDS functionalization to maximize the electrical characteristics of TIPS-P5-based devices.

The development of efficient, reliable, and clean energy sources is one of the global priorities for enabling a sustainable transition toward a green society and economy. The third‐generation solar cells, such as organic solar cells (OSCs) and perovskite solar cells (PSCs), are among the most promising platforms for the generation of electrical power from sunlight for a wide range of applications. However, the widespread diffusion of emerging photovoltaics technologies is hampered by issues occurring in the translation of laboratory‐scale R&D efforts to real settings. Herein, starting from a thorough survey of latest research on OSC and PSC technologies, critical factors related to fabrication and operation of solar cells, especially in terms of materials properties/requirements and beyond metrics built on efficiency only, are analyzed. On this basis, OSCs and PSCs are compared in terms of their potential in real application scenarios, also highlighting their peculiarities in view of their future large‐scale utilization.

In view of developing multifunctional OLETs, 2,3-thienoimide-ended oligothiophenes are proposed as ideal candidates to effectively ensure good ambipolar field-effect mobility, self-assembly capability and high luminescence in solid state.