CsPb2Br5 is a ternary halogen‐plumbate material with close characteristics to the well‐reported halide perovskites. Owing to its unconventional two‐dimensional structure, CsPb2Br5 is being looked at ...broadly for potential applications in optoelectronics. CsPb2Br5 investigations are currently limited to nanostructures and powder forms of the material, which present unclear and conflicting optical properties. In this study, we present the synthesis and characterization of CsPb2Br5 bulk single crystals, which enabled us to finally clarify the material's optical features. Our CsPb2Br5 crystal has a two‐dimensional structure with Pb2Br5− layers spaced by Cs+ cations, and exhibits approximately 3.1 eV indirect band gap with no emission in the visible spectrum.
The antisolvent paradox: Ternary halogen‐plumbate compounds like CsPb2Br5 are capturing the attention of the optoelectronic community. However, fundamental knowledge of their intrinsic properties is still missing. Here, we present the synthesis of CsPb2Br5 single crystals by an antisolvent‐vapor crystallization method and their characterization.
The solution process is the most widely used method to prepare perovskite absorbers for high performance solar cells due to its ease for fabrication and low capital cost. However, an insufficient ...level of reproducibility of the solution process is often a concern. Complex precursor solution chemistry is likely one of the main reasons for the reproducibility issue. Here we report the effects of triple cation lead mixed-halide perovskite precursor solution aging on the quality of the resulting films and the device performance. Our study revealed that precursor solution aging has a great influence on the colloidal size distribution of the solution, which then affects the phase purity of the films and device performance. We determined the optimum aging hours that led to the best device efficiency along with the highest reproducibility. Dynamic light scattering revealed the formation of micron-sized colloidal intermediates in the solution when aged longer than the optimum hours and further analysis along with X-ray diffraction measurements suggested there were two chemical origins of the large aggregates, FA-based and Cs-based complexes.
The solution process is the most widely used method to prepare perovskite absorbers for high performance solar cells due to its ease for fabrication and low capital cost.
Highly transparent and UV-resistant superhydrophobic arrays of SiO2-coated ZnO nanorods are prepared in a sequence of low-temperature (<150 °C) steps on both glass and thin sheets of PET (2 × 2 ...in.2), and the superhydrophobic nanocomposite is shown to have minimal impact on solar cell device performance under AM1.5G illumination. Flexible plastics can serve as front cell and backing materials in the manufacture of flexible displays and solar cells.
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•Robotic dry-cleaning improved the performance of a PV system by ∼0.25% per day.•The tested robotic system did not damage the panels in any measurable way.•The previously reported ...silicone foam brush proved successful during deployment.
The challenge of mitigating power loss in solar photovoltaic (PV) systems—due to dust—is critical to the economical deployment of solar in arid regions. These areas suffer from high aerosol concentration levels and frequent sand storms that lead to an accumulation of a layer of dust on the surface of solar arrays. The dust stays in place due to only slight and occasional rain fall. This paper presents the results from a study conducted on the effectiveness of dry cleaning solar panels, using an automated robotic cleaning system. The robotic cleaning system is part of a research program related to robotic dust mitigation technologies for solar panels, and includes a new type of brush, which uses silicone rubber foam flaps mounted onto an aluminum core. The study found that the robotic system, using this silicone rubber foam brush, was able to effectively minimize the impact of dust on the solar panels’ power output, providing an increase in power output versus the weekly-cleaned controls. This new brush shows promise for use in solar panel dust mitigation due to its effective cleaning performance and low cost, and does not induce any damage to the surface of the solar panels.
Although the electroconversion of carbon dioxide (CO2) into ethanol is considered to be one of the most promising ways of using CO2, the ethanol selectivity is less than 50% because of difficulties ...in designing an optimal catalyst that arise from the complicated pathways for the electroreduction of CO2 to ethanol. Several approaches including the fabrication of oxide‐derived structures, atomic surface control, and the Cu+/Cu interfaces have been primarily used to produce ethanol from CO2. Here, a combined structure with Cu+ and high‐facets as electrocatalysts is constructed by creating high‐facets of wrinkled Cu surrounded by Cu2O mesh patterns. Using chemical vapor deposition graphene growth procedures, the insufficiently grown graphene is used as an oxidation‐masking material, and the high‐facet wrinkled Cu is simultaneously generated during the graphene growth synthesis. The resulting electrocatalyst shows an ethanol selectivity of 43% at −0.8 V versus reversible hydrogen electrode, which is one of the highest ethanol selectivity values reported thus far. This is attributed to the role of Cu+ in enhancing CO binding strength, and the high‐facets, which favor C–C coupling and the ethanol pathway. This method for generating the combined structure can be widely applicable not only for electrochemical catalysts but also in various fields.
A combined structure with Cu+ and high‐facets is developed via insufficient graphene growth and a postoxidation process. The synthesized catalysts show high ethanol selectivity from the electrochemical CO2 reduction. The enhanced CO binding strength due to the introduction of Cu+ induces stable CO adsorption while maintaining high‐facet properties, resulting in a favorable CO–CO coupling reaction for C2 formation.
Use of Cu and Cu+ is one of the most promising approaches for the production of C2 products by the electrocatalytic CO2 reduction reaction (CO2RR) because it can facilitate CO2 activation and CC ...dimerization. However, the selective electrosynthesis of C2+ products on Cu0Cu+ interfaces is critically limited due to the low electrocatalytic production of ethanol relative to ethylene. In this study, a novel porous Cu/Cu2O aerogel network is introduced to afford high ethanol productivity by the electrocatalytic CO2RR. The aerogel is synthesized by a simple chemical redox reaction of a precursor and a reducing agent. CO2RR results reveal that the Cu/Cu2O aerogel produces ethanol as the major product, exhibiting a Faradaic efficiency (FEEtOH) of 41.2% and a partial current density (JEtOH) of 32.55 mA cm−2 in an H‐cell reactor. This is the best electrosynthesis performance for ethanol production reported thus far. Electron microscopy and electrochemical analysis results reveal that this dramatic increase in the electrosynthesis performance for ethanol can be attributed to a large number of Cu0Cu+ interfaces and an increase of the local pH in the confined porous aerogel network structure with a high‐surface‐area.
A Cu/Cu2O interconnected porous aerogel network exhibits remarkably high selectivity and productivity in ethanol electrosynthesis from CO2 (41.2% and 32.55mA cm−2 in an H‐cell). This high performance arises from a large population of Cu0Cu+ interfaces in the confined porous structure with a high surface area. This aerogel electrocatalyst is thought to be an appealing model for the commercial electrosynthesis of ethanol from CO2.
Ruthenium (Ru) is the most widely used metal as an electrocatalyst for nitrogen (N2) reduction reaction (NRR) because of the relatively high N2 adsorption strength for successive reaction. Recently, ...it has been well reported that the homogeneous Ru‐based metal alloys such as RuRh, RuPt, and RuCo significantly enhance the selectivity and formation rate of ammonia (NH3). However, the metal combinations for NRR have been limited to several miscible combinations of metals with Ru, although various immiscible combinations have immense potential to show high NRR performance. In this study, an immiscible combination of Ru and copper (Cu) is first utilized, and homogeneous alloy nanoparticles (RuCu NPs) are fabricated by the carbothermal shock method. The RuCu homogeneous NP alloys on cellulose/carbon nanotube sponge exhibit the highest selectivity and NH3 formation rate of ≈31% and −73 μmol h−1 cm−2, respectively. These are the highest values of the selectivity and NH3 formation rates among existing Ru‐based alloy metal combinations.
An atomic‐scale homogeneous alloy of immiscible metals is first implemented in electrocatalytic nitrogen reduction (NRR) by a unique carbothermal shock method. Atomic‐scale mixing of ruthenium and copper facilitates pivotal reaction steps in NRR, showing high selectivity and formation rate to ammonia. This paves the way for developing numerous potential homogeneous alloys of immiscible metal combinations for future efficient NRR electrocatalysts.
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