Improving the Performance of Si/PEDOT:PSS Hybrid Solar Cells with More Economical and Environmentally Friendly Alcohol Ether Solvents.

The photoelectric characteristics of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) films significantly affect the power conversion efficiency and stability of Si/PEDOT:PSS hybrid solar cells. In this paper, we investigated PEDOT:PSS modification with alcohol ether solvents (dipropylene glycol methyl ether (DPM) and propylene glycol phenyl ether (PPH)). The reduction of PSS content and the transformation of the PEDOT chain from benzene to a quinone structure in PEDOT:PSS induced by doping with DPM or PPH are the reasons for the improved conductivity of PEDOT:PSS films. DPM and PPH doping improves the quality of silicon with the PEDOT:PSS heterojunction and silicon surface passivation, thereby reducing the surface recombination of charge carriers, which improves the photovoltaic performance of Si/PEDOT:PSS solar cells. Comparing the power conversion performance (PCE) and air stability of Si/PEDOT:PSS solar cells with DPM (13.24%), DPH (13.51%), ethylene glycol (EG, 13.07%), and dimethyl sulfoxide (DMSO, 12.62%), it is suggested that doping with DPM and DPH can replace DMSO and EG to enhance the performance of Si/PEDOT:PSS solar cells. The EG and DMSO solvents not only have a certain toxicity to the human body but also are not environmentally friendly. In comparison to DMSO and EG, DPM and DPH are more economical and environmentally friendly, helping to reduce the manufacturing cost of Si/PEDOT:PSS solar cells and making them more conducive to their commercial applications.

Regulating Surface Defects to Achieve More Positive Light Soaking Effect in Perovskite Solar Cells.

The dynamic defect tolerance under light soaking is a crucial aspect of halide perovskites. However, the underlying physics of light soaking remains elusive and is subject to debate, exhibiting both positive and negative effects. In this investigation, we demonstrated that surface defects in perovskite films significantly impact the performance and stability of perovskite solar cells, closely correlated with light soaking behaviors. Removing the top surface layer through adhesive tape, the surface defect density noticeably decreases, leading to enhanced photoluminescence (PL) efficiency, prolonged carrier lifetime, and higher conductivity. Consequently, the power conversion efficiency (PCE) of solar cells improves from 17.70% to 20.5%. Furthermore, we confirmed a positive correlation between surface defects and the light soaking effect. Perovskite films with low surface defects surprisingly exhibit a 3-fold increase in PL intensity and an 85% increase in carrier lifetime under 500 s of continuous illumination at an intensity of 100 mW/cm2. Beyond the conventional strategy of suppressing defect trapping, we propose increasing the capability of dynamic defect tolerance as an effective strategy to enhance the optoelectronic properties and performance of perovskite solar cells.

Can thick metal-halide perovskite single crystals have narrower optical bandgaps with near-infrared absorption?

Metal-halide perovskite (MHP) single crystals are emerging as potential competitors to their polycrystalline thin-film counterparts. These materials have shown the specific feature of extended absorbance towards the near-infrared (NIR) region, which promises further extension of their applications in the field of photovoltaics and photodetectors. This notable expansion of absorbance has been explained by the narrower effective optical bandgap of MHP single crystals promoted by their large thickness over several micrometres to millimetres. Herein, the attributes of the material's thickness and the measurement technique used to estimate these characteristics are discussed to elucidate the actual origins of the extended absorbance of MHP single crystals. Contrary to the general belief of the narrower bandgap of the MHP single crystals, we demonstrate that the extended NIR absorption in the MHP single crystals mainly originates from the combination of unique below-bandgap absorption of MHPs, the thickness of single crystals, and the technical limitation of the spectrophotometer, with the key attributes of (i) significantly large thickness of the MHP single crystals by suppressing the transmitted light and (ii) the detector's limited dynamic range. Combining the theoretical and experimental characterizations, we clarify the significant role of the large thickness together with the limited sensitivity of the detector in promoting the well-known red shift of the absorption onset of the MHP single crystals. The observations evidently show that in some special circumstances, the acquired absorption spectrum cannot reliably represent the optical bandgap of MHP materials. This highlights some misinterpretations in the estimation of the narrower optical bandgap of the MHP single crystals from conventional optical methods, while the optical bandgap is an inherent property independent of the thickness. The proposed broad applications of the MHP single crystals are dictated by their fascinating properties, and therefore, a deep insight into these features should be considered besides device applications, because much of their property-function relationships are still ambiguous and a subject of debate.

Transcutaneous auricular vagus nerve stimulation ameliorates adolescent depressive- and anxiety-like behaviors via hippocampus glycolysis and inflammation response.

BACKGROUND: Transcutaneous auricular vagus nerve stimulation (taVNS) is a crucial neuromodulation therapy for depression, yet its molecular mechanism remains unclear. Here, we aim to unveil the underlying mechanisms of antidepression by systematically evaluating the change of gene expression in different brain regions (i.e., hippocampus, anterior cingulate cortex, and medial prefrontal cortex). METHODS: The adolescent depression rat model was established by chronic unpredictable mild stress (CUMS), followed by the taVNS treatment for 3 weeks. The open field test (OFT), forced swimming test (FST), elevated plus maze test (EPM), and new object recognition (NOR) test were used to evaluate depressive- and anxiety-like behaviors. Gene expression analysis of three brain regions was conducted by RNA sequencing (RNA-seq) and further bioinformatics methods. RESULTS: The depressive- and anxiety-like behaviors in CUMS-exposed rats were manifested by decreased spontaneous locomotor activity of OFT, increased immobility time of FST, increased entries and time in the closed arms of EPM, and decreased new object index of NOR. Furthermore, CUMS exposure also led to alterations in gene expression within the hippocampus (HIP), anterior cingulate cortex (ACC), and medial prefrontal cortex (mPFC), suggesting a potential link between adolescent stress and pathological changes within these brain regions. TaVNS could significantly ameliorate depressive- and anxiety-like behaviors. Its effects on these three brain regions were found related to regulation of the metabolism, and there were some brain region-specific findings. Compared with ACC and mPFC, taVNS has a more concrete effect on HIP by regulating the inflammation response and glycolysis. CONCLUSION: taVNS is capable of ameliorating adolescent depressive- and anxiety-like behaviors by regulating plenty of genes in the three brain regions. Suppressed level of inflammatory response and enhanced glycolysis manifests the dominant role of taVNS in HIP, which provides a theoretical foundation and data support for the molecular mechanism of antidepression by taVNS.

3D Melamine Sponge-Derived Cobalt Nanoparticle-Embedded N-Doped Carbon Nanocages as Efficient Electrocatalysts for the Oxygen Reduction Reaction.

The large-scale and controllable synthesis of novel N-doped three-dimensional (3D) carbon nanocage-decorated carbon skeleton sponges (Co-NCMS) is introduced. These Co-NCMS were highly active and durable non-noble metal catalysts for the oxygen reduction reaction (ORR). This hybrid electrocatalyst showed high ORR activity with a diffusion-limiting current of 5.237 mA·cm-2 in 0.1 M KOH solution through the highly efficient 4e- pathway, which was superior to that of the Pt/C catalyst (4.99 mA·cm-2), and the ORR Tafel slope is ca. 67.7 mV·dec-1 at a high potential region, close to that of Pt/C. Furthermore, Co-NCMS exhibited good ORR activity in acidic media with an onset potential comparable to that of the Pt/C catalyst. Most importantly, the prepared catalyst showed much higher stability and better methanol tolerance in both alkaline and acidic solutions. The power density obtained in a proton exchange membrane fuel cell was as high as 0.37 W·cm-2 at 0.19 V compared with 0.45 W·cm-2 at 0.56 V for the Pt/C catalyst. In Co-NCMS, the N-doped carbon nanocages facilitated the diffusion of the reactant, maximizing the exposure of active sites on the surface and protecting the active metallic core from oxidation. This made Co-NCMS one of the best non-noble metal catalysts and potentially offers an alternative approach for the efficient utilization of active transition metals in electrocatalyst applications.

Integrated ABR and UASB system for dairy wastewater treatment: Engineering design and practice.

This work designed and assessed the engineering performance of dairy wastewater treatment by an integrated system consisting of an anaerobic baffled reactor (ABR) and an upflow anaerobic sludge blanket (UASB). With fats adsorbed and decomposed, proteins were first denatured coagulated into solids in the ABR treatment process, and this process created suitable conditions for sludge retention in the sludge bed of the UASB. As a result, the combined system achieved a substantial reduction in excess sludge from 3 to 5 t/d to 3 t/m, notable biogas generation, and 98% COD removal, while the other pollutants in the effluent met relevant standards. In addition, the system attained an excellent performance in terms of the energy consumption and water treatment agent amount. Two active plants achieved operation costs lower than 0.5 kW h/t, while stable operations under ambient temperature conditions lasted longer than three years. Engineering practices both technically and economically affirmed the potential of the proposed system for dairy wastewater treatment.

Silver-Catalyzed Nucleophilic Addition of ß-Dicarbonyls to Isocyano Group: Facile Access to Indolin-3-ol Derivatives.

A domino silver-catalyzed intermolecularly nucleophilic addition of ß-dicarbonyls to the isocyano group and cyclization of the imidoyl silver sequence was developed for the direct and efficient synthesis of indolin-3-ol derivatives. This domino transformation tolerates a range of readily available o-acyl arylisocyanides and 1,3-dicarbonyls under an operationally simple procedure. Triple roles of silver carbonate are demonstrated in this reaction: (1) activation of isocyano group, (2) formation of enolate, and (3) promotion the nucleophilic reactivity of imidoyl intermediate.

Red Phosphor Rb2NbOF5:Mn4+ for Warm White Light-Emitting Diodes with a High Color-Rendering Index.

We successfully prepared a red-emitting phosphor Rb2NbOF5 doped with Mn4+, and investigated its crystal structure, luminescent properties, and applications in detail. Mn4+ ions in Rb2NbOF5 exhibit an intense red emission with high color purity upon a broad excitation in the blue region. The related crystal-field parameters of Mn4+ in Rb2NbOF5 have been estimated according to the luminescent spectra. More importantly, Rb2NbOF5:Mn4+ has high thermal-quenching resistance and color stability. We further fabricated a warm white light-emitting diode using the phosphor, emitting intense white light with a high color-rendering index of 90 and a low color temperature of 3418 K. The results indicate that Rb2NbOF5:Mn4+ is a potential red-emitting phosphor for white light-emitting diodes.

Novel red-emitting phosphors A2HfF6:Mn4+ (A = Rb+, Cs+) for solid-state lighting.

New red-emitting phosphors A2HfF6:Mn4+ (A = Rb+, Cs+) with a single phase have been successfully synthesized via a simple ion exchange method, and their structures and luminescence properties were investigated. It was found that Mn4+ ions in Rb2HfF6 and Cs2HfF6 who share wide band gaps can possess broad excitation bands in the blue regions and intense red emission with internal quantum yields of 0.556 and 0.652, respectively. Meanwhile, these red phosphors exhibit high chemical and thermal stabilities. A series of LED devices with a tunable color rendering index and color temperature were fabricated with these samples which can remarkably optimize the optical performances of white light-emitting diodes (w-LEDs). These results indicate that A2HfF6:Mn4+ phosphors can be promising red phosphors in w-LEDs.