RESUMO
van der Waals (vdW) layered materials have been shown to have excellent optoelectronic properties relevant to photovoltaics. Despite their promise, the demonstrated efficiencies of vdW material solar cells remain low and are seldom supported by statistics or spectral quantum efficiency analysis. In this study, we utilize a p-type WSe2 absorber, forming a solar cell with a transparent front InOx electron contact, and a rear Pd reflector/hole contact. We fabricate multiple devices providing statistics for 10 devices with an average 1 sun conversion efficiency above 5%, among which a champion efficiency of 6.37% is achieved. This is the highest AM 1.5G 1 sun efficiency reported for a vdW material solar cell, with a current density supported by external quantum efficiency analysis. This cell is also shown to have near unity quantum efficiency around λ = 600 nm. This work provides support to vdW materials being considered as serious candidates for future thin-film solar cells.
RESUMO
Defect sites present on the surface of catalysts serve a crucial role in different catalytic processes. Herein, we have investigated defect engineering within a hybrid system composed of "soft" polymer catalysts and "hard" metal nanoparticles, employing the disparity in their thermal expansions. Electron paramagnetic resonance, X-ray photoelectron spectroscopy, and mechanistic studies together reveal the formation of new abundant defects and their synergistic integrability with plasmonic enhancement within the hybrid catalyst. These active defects, co-localized with plasmonic Ag nanoparticles, promote the utilization efficiency of hot electrons generated by local plasmons, thereby enhancing the CO2 photoreduction activity while maintaining the high catalytic selectivity.
RESUMO
Black phosphorene quantum dots (BPQDs) are most commonly derived from high-cost black phosphorus, while previous syntheses from the low-cost red phosphorus (Pred ) allotrope are highly oxidised. Herein, we present an intrinsically scalable method to produce high quality BPQDs, by first ball-milling Pred to create nanocrystalline Pblack and subsequent reductive etching using lithium electride solvated in liquid ammonia. The resultant ~25â nm BPQDs are crystalline with low oxygen content, and spontaneously soluble as individualized monolayers in tertiary amide solvents, as directly imaged by liquid-phase transmission electron microscopy. This new method presents a scalable route to producing quantities of high quality BPQDs for academic and industrial applications.
RESUMO
Liquid methanol has the potential to be the hydrogen energy carrier and storage medium for the future green economy. However, there are still many challenges before zero-emission, affordable molecular H2 can be extracted from methanol with high performance. Here, we present noble-metal-free Cu-WC/W plasmonic nanohybrids which exhibit unsurpassed solar H2 extraction efficiency from pure methanol of 2,176.7 µmol g-1 h-1 at room temperature and normal pressure. Macro-to-micro experiments and simulations unveil that local reaction microenvironments are generated by the coperturbation of WC/W's lattice strain and infrared-plasmonic electric field. It enables spontaneous but selective zero-emission reaction pathways. Such microenvironments are found to be highly cooperative with solar-broadband-plasmon-excited charge carriers flowing from Cu to WC surfaces for efficient stable CH3OH plasmonic reforming with C3-dominated liquid products and 100% selective gaseous H2. Such high efficiency, without any COx emission, can be sustained for over a thousand-hour operation without obvious degradation.