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After establishing themselves as promising active materials in the field of solar cells, halide perovskites are currently being explored for fabrication of low‐cost, easily processable, and highly efficient light‐emitting diodes (LEDs). Despite this, the highest efficiencies reported for perovskite‐based LEDs (PeLEDs) are achieved through spin coating or vacuum evaporation deposition techniques, which are not adequate, in most of the cases, for an industrial‐scale production. Additionally, the long‐term stability is still a big handicap, even though all inorganic perovskites, such as CsPbBr3, are found to be more stable to external variables. In this context, herein, the fabrication of fully inkjet‐printed (IJP) CsPbBr3‐based PeLEDs in ambient conditions, on rigid and flexible substrates, on a proof‐of‐concept basis, with the successful incorporation of NiO and SnO2 as hole‐ and electron‐selective contacts, respectively, is reported. Despite the moderate luminance (324 cd m−2) value obtained, this result paves the way toward the development of upscalable fabrication of PeLEDs based on deposition techniques with controlled spatial resolution. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: The achievement of an efficient all‐Si electrically‐pumped light emitter is a major milestone in present optoelectronics still to be fulfilled. Silicon nanocrystals (Si NCs) are an attractive material which, by means of the quantum confinement effect, allow attaining engineered bandgap visible emission from Si by controlling the NC size. In this work, SiO2‐embedded Si NCs are employed as an active layer within a light‐emitting device structure. It is demonstrated that the use of an additional thin Si3N4 interlayer within the metal–insulator–semiconductor device design induces an enhanced minority carrier injection from the substrate, which in turn increases the efficiency of sequential carrier injection under pulsed electrical excitation. This results in a substantial increase in the electroluminescence efficiency of the device. Here, the effect of this Si3N4 interlayer on the structural, optical, electrical, and electro‐optical properties of a Si NC‐based light emitter is reported, and the physics underlying these results is discussed. [ABSTRACT FROM AUTHOR]

Multilayers consisting of silicon nanocrystals (Si NCs) and SiO2 are successfully fabricated by electron beam evaporation, using pure Si and SiO2 targets in an oxygen‐rich atmosphere for alternately depositing silicon‐rich oxide (SRO) layers and SiO2 barriers, respectively. A post‐deposition annealing process is carried out at different temperatures in order to achieve the Si precipitation in the form of nanocrystals. The stoichiometry of the layers is determined by X‐ray photoelectron spectroscopy, which confirms the controlled silicon oxidation in order to attain SRO layers. Transmission electron microscopy and Raman‐scattering measurements confirm the presence of crystalline Si‐nanoprecipitates. Photoluminescence spectra from the Si NC samples can be deconvolved into two contributions, whose dynamics suggest that two different luminescent centers are responsible for the optical emission of the samples. [ABSTRACT FROM AUTHOR]

Abstract: Fully compatible CMOS capacitive devices have been developed in order to obtain electrically stimulated luminescence. By high-temperature annealing in N2 atmosphere PECVD non-stoichiometric silica layers, silicon nanocrystals were formed. Photoluminescence, as well as structural studies, were carried out on these layers to decide the best material composition, which lies next to 17% of silicon excess. Under pulsed electrical stimulation, devices show sharp, narrow, less than 5μs and pulse-frequency-independent, luminescence peaks at the end of the stimulation pulse. Current analysis on those capacities show hole injection at the beginning and electron injection at the end of the stimulation pulses. It is seen that no positive pulses are needed for attaining bipolar charge injection. Electroluminescence is detected when biasing with negative pulses at about 15V and increasing up to 50V. The electroluminescence spectrum matches photoluminescence one, allowing assigning both luminescent radiation to the same emission mechanism, that is, electron–hole recombination within the silicon nanocrystals. [Copyright &y& Elsevier]

Abstract: Thin (50nm) erbium implanted silicon rich oxide films suitable for slot waveguides applications have been produced and studied by means of optical spectroscopy and structural characterisation techniques. Comparison between different deposition techniques in terms of light emitting properties of erbium ions is presented. Special attention is given to the efficiency improvement of the energy transfer from silicon nanoclusters to erbium ions where the type of annealing treatment is proven to be of crucial importance. [Copyright &y& Elsevier]