Correction: Carbon dots on LAPONITE® hybrid nanocomposites: solid-state emission and inter-aggregate energy transfer.

Correction for 'Carbon dots on LAPONITE® hybrid nanocomposites: solid-state emission and inter-aggregate energy transfer' by Bruno S. D. Onishi et al., Nanoscale, 2024, https://doi.org/10.1039/d3nr06336d.

Laponite-Modified Biopolymers as a Conformable Substrate for Optoelectronic Devices.

Biopolymers such as carboxymethyl cellulose and hyaluronic acid are alternative substrates for conformable organic light-emitting diodes (OLEDs). However, drawbacks such as mechanical stress susceptibility can hinder the device's performance under stretched conditions. To overcome these limitations, herein, we developed a nanocomposite based on CMC/HA (carboxymethyl cellulose/hyaluronic acid) and synthetic Laponite, intending to improve the mechanical strength without compromising the film flexibility and transparency (transmittance >80%; 380-700 nm) as substrates for conformable OLEDs. From XRD, FTIR, CP-MAS NMR, and TGA/DTG characterization techniques, it was possible to conclude the presence of Laponite randomly dispersed between the polymer chains. CMC/HA with 5% (w/w) Laponite, CMC/HA 5, presented a higher tensile strength (370.6 MPa) and comparable Young's modulus (51.0 ± 1.2 MPa) in comparison to the nanocomposites and pristine films, indicating a better candidate for the device's substrates. To produce the OLED, the multilayer structure ITO/MoO3/NPB/TCTA:Ir(ppy)3/TPBi:Ir(ppy)3/BPhen/LiF was deposited onto the CMC/HA 5 substrate. The OLEDs fabricated using CMC/HA 5 substrates showed higher luminance (12 kcd/m2) and irradiance (0.9 mW/cm2) values when compared with those based on commercial bacterial cellulose. However, the same device presented a lower efficiency (3.2 cd/A) due to a higher current density. Moreover, the OLED fabricated onto the Laponite-modified biopolymer presented reproducible behavior when submitted to continuous bending stress. Thus, CMC/HA 5 demonstrates potential as a transparent conductor substrate for biopolymer-based OLEDs with comparable performance to commercial bacterial cellulose features.

Unveiling the Solubilization of Potassium Mineral Rocks in Organic Acids for Application as K-Fertilizer.

Organic acids produced by soil microorganisms can be useful to promote the release of potassium (K) from potassium mineral rocks (KR), but the complexity of low reactivity minerals limits K solubilization and their use as fertilizer. Here, we investigate the ways that different organic acids (gluconic, oxalic, and citric) can affect the solubilization of potassium minerals, in order to propose process strategies to improve their solubility. For this, evaluations were performed using the model minerals KRpolyhalite (sedimentary mineral), KRfeldspar (igneous mineral), and KCl (commercial fertilizer). For KCl and KRpolyhalite, complete solubilization was achieved using all the organic acids, while for KRfeldspar, the highest K+ solubilization (34.86 mg L-1) was achieved with oxalic acid. The solubility of KRfeldspar was further investigated under submerged cultivation with the filamentous fungus Aspergillus niger, as well as after a mechanochemical grinding treatment. The biotechnological route resulted in solubilized K up to 63.2 mg L-1. The mechanochemical route, on the other hand, increased the release of K by about 8.6 times (993 mg L-1) compared to the natural mineral, due to the greater fragmentation of the particles after the treatment (with a surface area about 2.5 times higher than for the in natura KRfeldspar). These findings demonstrated the potential of applying biotechnological and mechanochemical routes with organic acids to improve the solubilization of K present in low reactivity mineral rocks, indicating the possible use of these minerals in more sustainable agricultural practices.

Strategy for Multinutrient Application in Integrated Granules Using Zein as a Coating Layer.

The efficiency of phosphate fertilizers is strongly limited by the acidity and high iron content and aluminum-based compounds in soils due to high P fixation. Coatings have been proposed as an alternative solution to reduce P losses by controlling the fertilizer release, but the literature is not conclusive about the most adequate material for that purpose. Herein we report a novel Zn-based coating for monoammonium phosphate (MAP) granules comprising ZnO nanoparticles and zein as a bicoating structure. Samples were prepared by dispersing ZnO and zein on the MAP surface and characterized, comparing the release in neutral and acidic solutions over time. Coating thickness/quality determined the nutrient release by a physical barrier effect. The results show that the zein coating overprotection avoids a fast nutrient release, keeping the local acid medium necessary to suppress ZnPO4 precipitation. A range of 2.5 to 10.0 wt % of zein was studied, indicating that 2.5 wt % coatings just present significant release control, which is similar until 10.0 wt % coating.

Role of Polymeric Coating on the Phosphate Availability as a Fertilizer: Insight from Phosphate Release by Castor Polyurethane Coatings.

The coating of fertilizers with polymers is an acknowledged strategy for controlling the release of nutrients and their availability in soil. However, its effectiveness in the case of soluble phosphate fertilizers is still uncertain, and information is lacking concerning the chemical properties and structures of such coatings. Here, an oil-based hydrophobic polymer system (polyurethane) is proposed for the control of the release of phosphorus from diammonium phosphate (DAP) granules. This material was systematically characterized, with evaluation of the delivery mechanism and the availability of phosphate in an acid soil. The results indicated that thicker coatings can change the maximum nutrient availability toward longer periods, such as 4.5-7.5 wt % DAP coated, that presented the highest concentrations at 336 h, as compared to 168 h for uncoated DAP. In contrast, DAP treated with 9.0 wt % began to increase the concentration after 168 h until it results in maximum release at 672 h. These effects could be attributed to the homogeneity of the polymer and the porosity. The strategy successfully provided long-term availability of a phosphate source.