Recent advances in metallic glass nanostructures: synthesis strategies and electrocatalytic applications

Recent advances in metallic glass nanostructures (MGNs) are reported, covering a wide array of synthesis strategies, computational discovery, and design solutions that provide insight into distinct electrocatalytic applications. A brief introduction to the development and unique features of MGNs with an overview of top-down and bottom-up synthesis strategies is presented. Specifically, the morphology and structural analysis of several examples applying MGNs as electrodes are highlighted. Subsequently, a comprehensive discussion of commonly employed kinetic parameters and their connection with the unique material structures of MGNs on individual electrocatalytic reactions is made, including the hydrogen evolution reaction, oxygen reduction reaction, and alcohol (methanol or ethanol) oxidation reaction. Finally, a summary of the challenges and perspective on the future research and development relevant to MGNs as electrocatalysts is provided.317FAPESP – FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2017/11958‐

Dust Abrasion Damage on Martian Solar Arrays: Experimental Investigation and Opportunity Rover Performance Analysis

Here we investigate the effects of erosion and weathering that occur on III-V cover-glass interconnected cells (CICs) after exposure to Mars dust storm conditions. The durability of these materials in a Martian environment is not well characterized so we perform analogous experimentation. To replicate the dust impingement, test coupons were placed in an enclosure and sandblasted with Mars dust simulant. We show the J-V response dependency on both incident angle and exposure times. We find that the simulated Martian dust storm often results in damage to the anti-reflective coating and subsequent reduced short circuit current. Reduction in the open circuit voltage is observed, likely caused by structural damage to the crystal lattice after CIC fracture. We employ data-driven modeling to determine a performance degradation rate that is consistent with zero within uncertainty. We also quantify the soiling contribution and power degradation of the photovoltaic cells on Mars through analysis of 4.95 Martian years of report-out power conditions from the Opportunity rover. We find that atmospheric dust suspended due to a weather event does not result in instantaneous settled dust on the PV cells. We calculate via autocorrelation function that the dust settling rate is approximately 21 Sols from atmospheric dust suspension. The findings presented here deliver a realistic approximation for the insolation values and subsequent PV power expected over time on the Martian surface thus informing future dust abatement systems

Dust Abrasion Damage on Martian Solar Arrays: Experimental Investigation and Opportunity Rover Performance Analysis

Here we investigate the effects of erosion and weathering that occur on III-V cover-glass interconnected cells (CICs) after exposure to Mars dust storm conditions. The durability of these materials in a Martian environment is not well characterized so we perform analogous experimentation. To replicate the dust impingement, test coupons were placed in an enclosure and sandblasted with Mars dust simulant. We show the J-V response dependency on both incident angle and exposure times. We find that the simulated Martian dust storm often results in damage to the anti-reflective coating and subsequent reduced short circuit current. Reduction in the open circuit voltage is observed, likely caused by structural damage to the crystal lattice after CIC fracture. We employ data-driven modeling to determine a performance degradation rate that is consistent with zero within uncertainty. We also quantify the soiling contribution and power degradation of the photovoltaic cells on Mars through analysis of 4.95 Martian years of report-out power conditions from the Opportunity rover. We find that atmospheric dust suspended due to a weather event does not result in instantaneous settled dust on the PV cells. We calculate via autocorrelation function that the dust settling rate is approximately 21 Sols from atmospheric dust suspension. The findings presented here deliver a realistic approximation for the insolation values and subsequent PV power expected over time on the Martian surface thus informing future dust abatement systems

Measured optical constants of Pd_(77.5)Cu_6Si_(16.5) bulk metallic glass

Optical constants of Pd_(77.5)Cu_6Si_(16.5) alloy were determined experimentally using spectroscopic ellipsometry measurements on bulk specimens. Values of the complex refractive index of the glassy metallic alloys are compared to their crystalline counterparts and to pure crystalline Pd. The presence of Cu and Si increase the occurrence of defects in the crystal lattice resulting in reduced refractive index in the crystalline alloy when compared to pure crystalline Pd. Moreover, we show the conduction band energy of each specimen using Tauc’s plot. The obtained complex refractive index across the spectrum (250 – 1500nm) allows for accurate prediction of optical performance within the investigated spectral range providing optimal design for optical devices

Charge Transfer From Carbon Nanotubes To Silicon In Flexible Carbon Nanotube/Silicon Solar Cells

Mechanical fragility and insufficient light absorption are two major challenges for thin flexible crystalline Si-based solar cells. Flexible hybrid single-walled carbon nanotube (SWNT)/Si solar cells are demonstrated by applying scalable room-temperature processes for the fabrication of solar-cell components (e.g., preparation of SWNT thin films and SWNT/Si p–n junctions). The flexible SWNT/Si solar cells present an intrinsic efficiency ≈7.5% without any additional light-trapping structures. By using these solar cells as model systems, the charge transport mechanisms at the SWNT/Si interface are investigated using femtosecond transient absorption. Although primary photon absorption occurs in Si, transient absorption measurements show that SWNTs also generate and inject excited charge carriers to Si. Such effects can be tuned by controlling the thickness of the SWNTs. Findings from this study could open a new pathway for designing and improving the efficiency of photocarrier generation and absorption for high-performance ultrathin hybrid SWNT/Si solar cells

PEOz-PEDOT:PSS Composite Layer: A Route to Suppressed Hysteresis and Enhanced Open-Circuit Voltage in a Planar Perovskite Solar Cell

The successful commercialization of perovskite solar cells (Pvs-SCs) calls for the need to find low-temperature processable interlayers with outstanding charge-transport features. In this work, we strategically blend poly­(2-ethyl-2-oxazoline) (PEOz) with PEDOT:PSS as the modified hole transport layer (HTL) to achieve high-efficiency P–I–N CH₃NH₃PbI₃ Pvs-SCs. The PEOz-PEDOT:PSS HTL exhibits enhanced features over the conventional layer including the following: (1) promoting perovskite with enlarged grain sizes to decrease the perovskite layer’s recombination, (2) increasing the work function of the HTL, and (3) decreasing the noncapacitive current in Pvs-SCs. Remarkably, we demonstrate a 17.39% power conversion efficiency with very low hysteresis and high <i>V</i>_oc values of 1.075 V for Pvs-SCs with PEOz-PEDOT:PSS