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This study presents an innovative method for the synthesis of indium aluminum nitride (InAlN) layers by direct current (DC) co-sputtering at room temperature, with the aim of reducing production costs of optoelectronic devices. Indium and aluminum targets are used, varying the power applied to the aluminum target. The results show that increasing the target power favors the formation of aluminum nitride (AlN), which modifies the chemical composition of the material. The layers obtained present smooth surfaces with a roughness of less than 3 nm, which is beneficial for applications requiring interfaces with low defect density. Regarding the optical properties, it is observed that the optical bandgap varies between 1.8 eV and 2.0 eV, increasing with the target power. Hall effect measurements indicate a decrease in the free carrier concentration and an increase in the resistivity with increasing power. This approach allows for the synthesis of InAlN with properties suitable for optoelectronic applications, solar cells, photocatalysis, and photoelectrocatalysis at low cost. [ABSTRACT FROM AUTHOR]

Abstract The present work deals with developing a method for revalorizing steel residues to create sunlight-active photocatalysts based on iron oxides. Commercial-grade steel leftovers are oxidized under different combinations of pH and temperature (50–90 °C and 3 ≥ pH ≤ 5) in a low energy-intensive setup. The material with the highest production efficiency (yield > 12%) and magnetic susceptibility (χm = 387 × 10−6 m3/kg) was further explored and modified by diffusion of M2+ (Zn and Co) ions within the structure of the oxide using a hydrothermal method to create ZnFe2O4, CoFe2O4 and combined Co–Zn ferrite. (Co–Zn)Fe2O4 displayed a bandgap of 2.02 eV and can be activated under sunlight irradiation. Electron microscopy studies show that (Co–Zn)Fe2O4 consists of particles with diameters between 400 and 700 nm, homogeneous size, even distribution, and good dispersibility. Application of the developed materials in the sunlight catalysis of black liquors from cellulose extraction resulted in a reduction of the Chemical Oxygen Demand (− 15% on average) and an enhancement in biodegradability (> 0.57 BOD/COD) after 180 min of reaction. Since the presented process employs direct solar light, it opens the possibility to large-scale water treatment and chemical upgrading applications.

The present work deals with developing a method for revalorizing steel residues to create sunlight-active photocatalysts based on iron oxides. Commercial-grade steel leftovers are oxidized under different combinations of pH and temperature (50–90 °C and 3 ≥ pH ≤ 5) in a low energy-intensive setup. The material with the highest production efficiency (yield > 12%) and magnetic susceptibility (χm = 387 × 10−6 m3/kg) was further explored and modified by diffusion of M2+ (Zn and Co) ions within the structure of the oxide using a hydrothermal method to create ZnFe2O4, CoFe2O4 and combined Co–Zn ferrite. (Co–Zn)Fe2O4 displayed a bandgap of 2.02 eV and can be activated under sunlight irradiation. Electron microscopy studies show that (Co–Zn)Fe2O4 consists of particles with diameters between 400 and 700 nm, homogeneous size, even distribution, and good dispersibility. Application of the developed materials in the sunlight catalysis of black liquors from cellulose extraction resulted in a reduction of the Chemical Oxygen Demand (− 15% on average) and an enhancement in biodegradability (> 0.57 BOD/COD) after 180 min of reaction. Since the presented process employs direct solar light, it opens the possibility to large-scale water treatment and chemical upgrading applications. [ABSTRACT FROM AUTHOR]

Quest for efficient and lead-free perovskite absorber layer is the need of the hour. The less explored titanium-based halide perovskites might be the non-toxic answer for the efficient yet toxic, organic, lead-based halide perovskite. It is of great interest to synthesize cesium titanium iodide perovskite and to investigate their novel properties. We have reported the synthesis of vacancy-ordered double perovskite cesium titanium iodide (Cs2TiI6) at room temperature. Structural, electrical and optical properties are investigated. Broad photoluminescence spectrum is observed. Absorbance and stability of this compound are discussed in detail. Using the absorption data, we have simulated solar cells with different transport layers to give an insight into its application. [ABSTRACT FROM AUTHOR]

This study presents an innovative method for the synthesis of indium aluminum nitride (InAlN) layers by direct current (DC) co-sputtering at room temperature, with the aim of reducing production costs of optoelectronic devices. Indium and aluminum targets are used, varying the power applied to the aluminum target. The results show that increasing the target power favors the formation of aluminum nitride (AlN), which modifies the chemical composition of the material. The layers obtained present smooth surfaces with a roughness of less than 3 nm, which is beneficial for applications requiring interfaces with low defect density. Regarding the optical properties, it is observed that the optical bandgap varies between 1.8 eV and 2.0 eV, increasing with the target power. Hall effect measurements indicate a decrease in the free carrier concentration and an increase in the resistivity with increasing power. This approach allows for the synthesis of InAlN with properties suitable for optoelectronic applications, solar cells, photocatalysis, and photoelectrocatalysis at low cost.

The active layer of organic solar cells (OSCs) is composed of a p-type conjugated polymer as the donor and an n-type organic semiconductor as the acceptor. Since the report of bulk-heterojunction OSCs with soluble C60 derivative PCBM as the acceptor in 1995, fullerene derivatives, including PCBM and the C70 derivative PC71BM, have been the dominant acceptors in OSCs for 20 years. In 2015, the A–D–A structured small molecule acceptor (SMA) was developed, which possesses the advantages of a narrow bandgap, strong absorption in the long wavelength region, and suitable electronic energy levels, in contrast to the fullerene derivative acceptors. A–D–A SMAs boost the power conversion efficiency (PCE) of OSCs to the 10–14% level. Recently, benefiting from the innovation of A–DA′D–A structured SMAs, the PCE of OSCs has rapidly increased from 15% to 19%. In this review, the development history of n-type organic semiconductor acceptor materials is briefly introduced. The molecular structures and the physicochemical and photovoltaic properties of acceptors, including fullerene derivatives and narrow bandgap SMAs, are described. In particular, the effect of regulating the molecular packing and miscibility of SMAs on their photovoltaic performance is discussed. Finally, current challenges and prospects for n-type organic semiconductor acceptors are analyzed and discussed.

Nanoparticles can enhance the intensity of susceptible vibrational modes through electromagnetic or chemical enhancement mechanisms responsible for the SERS effect (Surface-enhanced Raman spectroscopy). In the present work, copper nanoparticles (CuNP) with diameters between 3 and 10 nm were obtained by a simple method using rongalite and gelatin. The UV–Vis spectrum showed a well-defined absorption band centered at 570 nm, attributed to the surface plasmon resonance (SPR) of CuNP in a colloidal solution. The SERS effect was analyzed on the pyridine (Py) molecule, observing an enhancement in the radial breathing mode of Py. Complementarily, Cu4n clusters (with n = 1–5) were modeled under the DFT (Density Functional Theory) framework at the B3LYP (Becke, 3-parameter, Lee–Yang–Parr) approximation level in combination with the LANL2DZ base set (Los Alamos National Laboratory 2 Double-Zeta). After analyzing the molecular descriptors, the Cu4n-Py interaction study provided hints of SERS behavior. [ABSTRACT FROM AUTHOR]

Perovskite solar cells deliver high efficiencies, but are often made from high‐cost bespoke chemicals, such as the archetypical hole‐conductor, 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxy‐phenylamine)‐9‐9′‐spirobifluorene (spiro‐OMeTAD). Herein, new charge‐transporting carbazole‐based enamine molecules are reported. The new hole conductors do not require chemical oxidation to reach high power conversion efficiencies (PCEs) when employed in n‐type‐intrinsic‐p‐type perovskite solar cells; thus, reducing the risk of moisture degrading the perovskite layer through the hydrophilicity of oxidizing additives that are typically used with conventional hole conductors. Devices made with these new undoped carbazole‐based enamines achieve comparable PCEs to those employing doped spiro‐OMeTAD, and greatly enhanced stability under 85 °C thermal aging; maintaining 83% of their peak efficiency after 1000 h, compared with spiro‐OMeTAD‐based devices that degrade to 26% of the peak PCE within 24 h. Furthermore, the carbazole‐based enamines can be synthesized without the use of organometallic catalysts and complicated purification techniques, lowering the material cost by one order of magnitude compared with spiro‐OMeTAD. As a result, we calculate that the overall manufacturing costs of future photovoltaic (PV) modules are reduced, making the levelized cost of electricity competitive with silicon PV modules. [ABSTRACT FROM AUTHOR]