Lead-free PEA₂SnI₄-based perovskite LEDs are successfully inkjet-printed on rigid and flexible substrates. Red-emitting devices (λ_max = 633 nm) exhibit, under ambient conditions, a maximum external quantum efficiency (EQE_max) of 1% with a related brightness of 30 cd/m² at 10 mA/cm².

Metal halide perovskites (MHPs) have shown outstanding optical emissive properties and can be employed in several optoelectronics devices. In contrast with materials of well‐established technologies, which are prone to degradation or require expensive processes, MHPs can be obtained by solution processing methods and increase stability. Inkjet printing is proposed as an industrial friendly technique to deposit MHPs. The inks have been developed from colloidal CsPbBr₃ nanocrystals and printing procedures that allow the deposition of thin layers with intense green emission. High emissive printed layers are assured by carrying out thermal annealing in vacuum oven, which is demonstrated to promote compact layers with low roughness, corroborated by SEM and AFM. XRD measurements show CsPbBr₃ crystalline layers with cubic symmetry and XPS provides insight into the stoichiometric composition and local bonding. Optical properties of inkjet‐printed CsPbBr₃ films have been analyzed by UV–vis absorbance and photoluminescence (PL), to extract the bandgap energy and photoluminescence quantum yield (PLQY). CsPbBr₃ printed layers emit at 524 nm with a narrow emission (FWHM ≈ 15 nm), exhibiting a PLQY up to 20%. These results enabled the large‐scale fabrication by inkjet printing of CsPbBr₃ color conversion layers (CCLs) and pave the way for flexible LEDs.

The resistive switching properties of ITO/ZnO/p-Si devices have been studied, which present well-defined resistance states with more than five orders of magnitude difference in current. Both the high resistance state (HRS) and the low resistance state (LRS) were induced by either sweeping or pulsing the voltage, observing some differences in the HRS. Finally, the charge transport mechanisms dominating the pristine, HRS, and LRS states have been analyzed in depth, and the obtained structural parameters suggest a partial re-oxidation of the conductive nanofilaments and a reduction of the effective conductive area.

In the last few years, the emergence of studies concerning the resistive switching (RS) phenomenon has resulted in the finding of a large amount of materials being capable of acting as an active layer in such devices, i.e., the layer where the change in resistance takes place. Whereas the normal operation consists of the electrical readout of the modified resistance state of the device after electrical writing, electro-photonic approaches seek the involvement of light in these devices, be it either for the active Set or Reset operations or the readout. We propose in this work silicon nanocrystal multilayers (Si NC MLs) as an active material for being used in RS devices, taking advantage of their outstanding optical properties. The resistance states of Si NC MLs were obtained by electrical excitation, whose readout is carried out by electrical and electro-optical means, thanks to a distinguishable electroluminescence emission under each state. To achieve this, we report on an adequate design that combines both the Si NC MLs with ZnO as a transparent conductive oxide, whose material properties ensure the device RS performance while allowing the electro-optical characterization. Overall, such an occurrence states the demonstration of a Si NCs-based electroluminescent RS device, which paves the way for their future integration into photonic integrated circuits.

We report on light-activated electroforming of ZnO/p-Si heterojunction memristors with transparent indium tin oxide as the top electrode. Light-generated electron-hole pairs in the p-type substrate are separated by the external electric field and electrons are injected into the active ZnO layer. The additional application of voltage pulses allows achieving different resistance states that end up in the realization of the low resistance state (LRS). This process requires much less voltage compared to dark conditions, thus avoiding undesired current overshoots and achieving a self-compliant device. The transport mechanisms governing each resistance state are studied and discussed. An evolution from an electrode-limited to a space charge-limited transport is observed along the electroforming process before reaching the LRS, which is ascribed to the progressive formation of conductive paths that consequently induce the growth of conductive nanofilaments through the ZnO layer.

In this paper, we investigated how different growth conditions (i.e., temperature, growth time, and composition) allows for trading off cost (i.e., In content) and performance of nanostructured indium tin oxide (ITO) for biosensing applications. Next, we compared the behavior of these functionalized nanostructured surfaces obtained in different growth conditions between each other and with a standard thin film as a reference, observing improvements in effective detection area up to two orders of magnitude. This enhanced the biosensor’s sensitivity, with higher detection level, better accuracy and higher reproducibility. Results show that below 150 °C, the growth of ITO over the substrate forms a homogenous layer without any kind of nanostructuration. In contrast, at temperatures higher than 150 °C, a two-phase temperature-dependent growth was observed. We concluded that (i) nanowire length grows exponentially with temperature (activation energy 356 meV) and leads to optimal conditions in terms of both electroactive surface area and sensitivity at around 300 °C, (ii) longer times of growth than 30 min lead to larger active areas and (iii) the In content in a nanostructured film can be reduced by 10%, obtaining performances equivalent to those found in commercial flat-film ITO electrodes. In summary, this work shows how to produce appropriate materials with optimized cost and performances for different applications in biosensing.