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Based on a circular bioeconomy strategy, eucalypt wood fines rejected from a Kraft pulp line were used as starting material in a pilot-scaled fast-pyrolysis process. The bio-oil and its coproducts were characterized regarding their physical, chemical, and thermal aspects. We put in perspective their properties to bring forward considerations for applications on biofuels, materials, and precursors. The yields of the pilot-scaled fast-pyrolysis process reached interesting values even if compared with optimized laboratory conditions. The results indicated the highest heating values (22–27 MJ/kg) for bio-oil, char, and crust material. The higher water content of aqueous extract had a negative effect for its application as fuel. The lignin/carbohydrate ratio for the bio-oil (2.82) and aqueous extract (0.53) identified a higher concentration of lignin-derived compounds in the first, mainly syringyl units. Bio-oil and aqueous extract presented chemical compounds with many functionalities, such as syringaldehyde and levoglucosan, expanding their potential application for higher value-added products besides energy.

Herein, the long-term stability of vacuum-deposited methylammonium lead iodide (MAPbI(3)) perovskite solar cells (PSCs) with power conversion efficiencies (PCEs) of around 19% is evaluated. A low-temperature atomic layer deposition (ALD) Al2O3 coating is developed and used to protect the MAPbI(3) layers and the solar cells from environmental agents. The ALD encapsulation enables the MAPbI(3) to be exposed to temperatures as high as 150 degrees C for several hours without change in color. It also improves the thermal stability of the solar cells, which maintain 80% of the initial PCEs after aging for approximate to 40 and 37days at 65 and 85 degrees C, respectively. However, room-temperature operation of the solar cells under 1sun illumination leads to a loss of 20% of their initial PCE in 230h. Due to the very thin ALD Al2O3 encapsulation, X-ray diffraction can be performed on the MAPbI(3) films and completed solar cells before and after the different stress conditions. Surprisingly, it is found that the main effect of light soaking and thermal stress is a crystal reorientation with respect to the substrate from (002) to (202) of the perovskite layer, and that this reorientation is accelerated under illumination.

A versatile Ru(II) complex bearing an anthracene moiety was synthesized in our search for suitable compounds towards efficient molecular devices. The new engineered dye, cis‑[Ru(dcbH2)(NCS)2(mbpy‑anth)] (dcbH2 = 2,2′‑bipyridyl‑4,4′‑dicarboxylic acid, mbpy‑anth = 4‑[N‑(2‑anthryl)carbamoyl]‑4′‑methyl‑2,2′‑bipyridine), exhibits a blueish emission in a vibronically structured spectrum ascribed to the fluorescence of a 1LCAnth (ligand centered) excited state in the anthracene and has a potential to be exploited in the fields of smart lighting and displays. This complex was also employed in dye-sensitized solar cells with fairly efficient solar energy conversion with the use of self-assembled TiO2 compact layers beneath the TiO2 mesoporous film to prevent meso‑TiO2/dye back reactions. Further photoelectrochemical investigations through incident photon-to-current efficiency and electrochemical impedance spectra showed that the all-nano-TiO2 compact layer acts as contact layers that increase the electron harvesting in the external circuit, enhancing efficiencies up to 50%.

The photophysical dynamics of three complexes in the highly-emissive [Ir(pqi)2(NN)]+ series were investigated aiming at unique photophysical features and applications in light-emitting and singlet oxygen sensitizing research fields. Rational elucidation and Franck–Condon analyses of the observed emission spectra in nitrile solutions at 298 and 77 K reveal the true emissive nature of the lowest-lying triplet excited state (T1), consisting of a hybrid 3MLCT/LCIr(pqi)→pqi state. Emissive deactivations from T1 occur mainly by very intense, yellow-orange phosphorescence with high quantum yields and radiative rates. The emission nature experimentally verified is corroborated by theoretical calculations (TD-DFT), with T1 arising from a mixing of several transitions induced by the spin–orbit coupling, majorly ascribed to 3MLCT/LCIr(pqi)→pqi and increasing contributions of 3MLCT/LLCTIr(pqi)→NN. The microsecond-lived emission of T1 is rapidly quenched by molecular oxygen, with an efficient generation of singlet oxygen. Our findings show that the photophysics of [Ir(pqi)2(NN)][PF6] complexes is suitable for many applications, from the active layer of electroluminescent devices to photosensitizers for photodynamic therapy and theranostics.

Sol–gel chemistry has been extensively employed to produce several classes of materials (e.g. nanoparticles, thin films, fibers, gels, glasses and ceramic powders) with desired easily-controllable morphological, crystallographic and mechanical properties. In particular, the methodology can be explored for the development of optical supramolecular materials with interesting properties for light-emitting devices, chemical and biological sensing, biomarking and targeting, among many others. To this end, the strategies usually adopted consist of embedding a luminescent guest species into normally non-emissive sol–gel host materials, resulting in optical systems that preserve both the guest's photophysical characteristics and the host's mechanical and morphological properties. This concise review provides insights into the development of promising new host–guest optical materials based on versatile sol–gel hosts (i.e. mesoporous MCM-41 nanoparticles, mesoporous sodium-aluminosilicate glasses and other mesoporous matrices for sensors) and highly luminescent guests (i.e. organic dyes, d6 complexes and lanthanide complexes), mostly focusing on the findings from our group and similar findings in the literature of the past decade.

The aim of this study is to enhance the use of agro-industrial byproducts and to address the environmental concerns by a novel method of co-production of thermoplastic composites with a solid residue constituting biorefinery. Accordingly, the reuse of 10–30 wt. % solid residues (SRH) from the enzymatic hydrolysis of recycled paper sludge (PS) in the production of thermoplastic composites with polypropylene (PP) was investigated. Thermal properties, water absorption, tensile strength and morphology of the prepared composites were evaluated. Higher thermal stability, rougher and wetter surface, and characteristics of a brittle material were observed in PP-SRH composites in comparison to the pristine PS-PP composites and the neat PP. The water absorption increased with increasing amount of SRH, but in lower proportion compared to other common raw materials used in the preparation of composites. Use of SRH resulted in similar or better properties compared to the composites made with the unhydrolyzed paper sludge, suggesting that SRH has potential for recycling and utilization as filler in the development of thermoplastic composites.

The increasing demand for electrical energy by a longer living and increasing population justifies the search for new, more efficient lighting systems. In this context, organo-metallic compounds have been largely investigated as efficient materials for organic light emitting diodes (OLEDs). Special interest has been demonstrated for neutral copper(I) complexes due to their high emission quantum efficiency and fast photoluminescence response time. In particular, Cu(I) complexes that present thermally activated delayed fluorescence (TADF) are one of the most promising materials for the next generation of lighting devices. In this work, we present an overview of the development of OLEDs, by comparing the mechanisms and efficiencies of different complexes and discussing the reasons why Cu(I) complexes have potential to be one of the most efficient alternatives for energy saving in lighting. Keywords: Light emitting devices, OLED, TADF, Cu(I) complexes

Hole transport layers HTLs are of fundamental importance in perovskite solar cells PSCs , as they must ensure an efficient and selective hole extraction, and ohmic charge transfer to the corresponding electrodes. In p i n solar cells, the ITO HTL is usually not ohmic, and an additional interlayer such as MoO3 is usually placed in between the two materials by vacuum sublimation. In this work, we evaluated the properties of the MoO3 TaTm TaTm is the HTL N4,N4,N4 amp; 8243;,N4 amp; 8243; tetra [1,1 amp; 8242; biphenyl] 4 yl [1,1 amp; 8242; 4 amp; 8242;,1 amp; 8243; terphenyl] 4,4 amp; 8243; diamine hole extraction interface by selectively annealing either MoO3 prior to the deposition of TaTm or the bilayer MoO3 TaTm without pre treatment on the MoO3 , at temperature ranging from 60 to 200 C. We then used these p contacts for the fabrication of a large batch of fully vacuum deposited PSCs, using methylammonium lead iodide as the active layer. We show that annealing the MoO3 TaTm bilayers at high temperature is crucial to obtain high rectification with low non radiative recombination, due to an increase of the electrode work function and the formation of an ohmic interface with TaTm

With population growth and increasing industrialization, enormous amounts of agro-industrial wastes are being produced. Without proper use, these keep piling up leading to tremendous pressure on environmental safety. There is also considerable economic interest not only in the proper utilization of these wastes, but also in developing appropriate processes for this purpose. Sludge generated in pulp and paper mills is one of such solid wastes. Although several studies have investigated its reuse, it is still disposed mostly in landfills, leading to environmental pollution. Utilization of this waste could economically benefit for the pulp and paper sector. An innovative and potentially valuable solution seems to be converting it into ethanol, on which a considerable number of reports have published diverse reviews, even though improvements in the technology are still needed. Hence, this study attempts to provide an overview of all studies carried out so far, highlighting key scientific and technological barriers for scaling up and implementing the conversion process. Some suggestions for future research are given, while perspectives and projections point out that adoption of this process could be especially interesting for regions such as Europe and Asia, where the generation of sludge is high and the ethanol production capacity is still low.

Vacuum-deposition of perovskite solar cells can achieve efficiencies rivalling solution-based methods and it allows for more complex device stacks. MoO3 has been used to enhance carrier extraction to the transparent bottom electrode in a p-i-n configuration, here we show that by inserting an organic charge transport molecule it can also be used on the top of a perovskite absorber in a n-i-p configuration. This strategy enables the first vacuum-deposited perovskite solar cells with metal oxides as charge transporting layers for both electrons and holes leading to power conversion efficiency > 19 %.

​This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acsami.9b04991, A variety of experiments on vacuum-deposited methylammonium lead iodide perovskite solar cells are presented, including JV curves with different scan rates, light intensity-dependent open-circuit voltage, impedance spectra, intensity-modulated photocurrent spectra, transient photocurrents, and transient voltage step responses. All these experimental data sets are successfully reproduced by a charge drift-diffusion simulation model incorporating mobile ions and charge traps using a single set of parameters. While previous modeling studies focused on a single experimental technique, we combine steady-state, transient, and frequency-domain simulations and measurements. Our study is an important step toward quantitative simulation of perovskite solar cells, leading to a deeper understanding of the physical effects in these materials. The analysis of the transient current upon voltage turn-on in the dark reveals that the charge injection properties of the interfaces are triggered by the accumulation of mobile ionic defects. We show that the current rise of voltage step experiments allow for conclusions about the recombination at the interface. Whether one or two mobile ionic species are used in the model has only a minor influence on the observed effects. A delayed current rise observed upon reversing the bias from +3 to -3 V in the dark cannot be reproduced yet by our drift-diffusion model. We speculate that a reversible chemical reaction of mobile ions with the contact material may be the cause of this effect, thus requiring a future model extension. A parameter variation is performed in order to understand the performance-limiting factors of the device under investigation.

Finding innovative solutions to manage waste and to expand the production of biofuels are some of the current challenges. Pulp and paper sectors, including recycled paper mills, produce a large amount of solid wastes, such as wastewater sludge containing non-recyclable short fibres. This study aimed to: (1) characterize recycled paper sludge; (2) define conditions for enzymatic hydrolysis and (3) evaluate two processes for ethanol production from the sludge: separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF). The waste showed a very high content of ash (58 %), which negatively affected enzyme action. A commercial enzyme cocktail (Cellic® CTec2) was used for the saccharification, at 43 °C and 6 % dosage. The highest ethanol yield (55.7 %) with shorter residence time (72 h) resulted from the SSF process. The best performance using the SHF process yielded 45.8 % after 84 h. Despite the intermediate results, sludge from pulp and paper mills could be an attractive raw material due to its low price and not requiring a pretreatment step for delignification. This application could be especially interesting for regions where the generation of paper sludge is high and the ethanol production capacity is still low, such as Asia.

Cyclometalated IrIII complexes are promising candidates for biomedical applications but high cytotoxicity limits their use as imaging and sensing agents. We herein introduce the use of Laponite as carrier for triplet-emitting cyclometalated IrIII complexes. Laponite is a versatile nanoplatform because of its biocompatibility, dispersion stability and large surface area that readily adsorbs functional nonpolar and cationic molecules. These inorganic-organic hybrid nanomaterials mask cytotoxicity, show efficient cell uptake and increase luminescent properties and photostability. By camouflaging intrinsic cytotoxicity, this simple method potentially extends the palette of available imaging and sensing dyes to any metal-organic complexes, especially those that are usually cytotoxic.

Functional foods are one of new trends for the food industry and nanotechnology can be useful for enrichment of food or parts of the food with natural bioactive compounds. Besides the introduction of nutraceuticals into food, nanotechnology may allow the protection of the functional compounds against degradation, and, furthermore, improve their bioavailability. Nanocapsules of biomacromolecules can be employed for entrapment of sensitive hydrophobic nutraceuticals with partial protection against photochemical degradation to enrich food products without modifying sensory properties. Insoluble fibers from plants can be employed to improve intestinal tract and decrease cholesterol and sugar absorption into blood. Besides, nanoparticles or nanofibers would be useful for jellification or emulsions, which have great potential for beverage applications associated with delivery of bioactives. However, some nanomaterials, mainly inorganic crystalline ones, may have toxic effects in the body and proper steps should be taken before recommending them for industrial applications. There are many processes for obtaining nanomaterials, which may belong to either bottom-up and top-down approach. This chapter focuses on some of these aspects along with some perspectives.

In this work, mesoporous anatase submicrospheres, consisted of packed individual 6 nm nanocrystallites, were prepared by hydrolysis of titanium glycolate and compared with TiO 2 nanoparticles obtained by the hydrothermal method. The submicrometer spheres show an average diameter of 0.40 μm, while the TiO 2 nanoparticle diameter is 20 nm. Here, we developed a screen-printable submicrosphere paste to deposit bifunctional films with increased light scattering and higher dye uptake. In dye-sensitized solar cells, these films lead to a 32% increase in conversion efficiencies when compared to those with standard TiO 2 nanoparticles and can be even improved after TiCl 4 post-treatment.

In this work, extracts of mulberry (Morus alba L.), jaboticaba’s skin (Mirtus cauliflora Mart), java plum (Eugenia Jambolana Lam) and pomegranate (Punica Granatum) were used as solar cell sensitizers, exhibiting unique spectra due to intrinsic characteristics of each fruit. Natural-dye-sensitized solar cells showed improved photocurrents using pyridine-free, low-viscosity electrolytes. A nano-TiO2 compact layer was employed between the conducting glass (FTO) surface and the meso-TiO2 film aiming further efficiency enhancements to these DSCs sensitized by fruit extracts, leading to increased current densities and photon-to-current efficiencies along with improvements in open circuit potentials, dark currents and electron lifetimes. These results indicate that the compact layer is effective to improve the electron harvesting at the external circuit and to prevent the FTO/electrolyte electronic recombination, enhancing global efficiencies up to 66%.

The heteroleptic [Ir(Fppy) 2 (Mepic)] complex exhibits an intense sky-blue phosphorescence (λ max = 474 nm; CIE color coordinates: x = 0.14 and y = 0.29) and a unitary quantum yield (ϕ = 0.98) in acetonitrile from a distinct triplet excited state of mixed 3 MLCT/LLCT characters. [Ir(Fppy) 2 (Mepic)] as a guest in a poly-(9-vinylcarbazole) (PVK) host matrix leads to energy transfer from the polymer to the complex, resulting in the complex’s blue emission with quenching of the PVK fluorescence. The active layer of an operational organic light-emitting diode (OLED) with PVK:[Ir(Fppy) 2 (Mepic)] film had its optoeletronic properties characterized by current-voltage curve and electroluminescent spectrum. The device exhibits a space-charge limited current and its illumination occurs after reaching the trap-filled limit at 35 V. This work is a successful proof of concept for a feasible low-cost sky-blue OLED with a simple architecture and fabrication methods that require non-specific instruments.