434 research outputs found
A modified template-removal process to improve the specific surface area and hierarchical porosity of carbon materials
No full textCaCO3-templating is a strategy for synthesizing porous carbon (PC) materials that has been widely used for decades. In this work, a modified template-removal process, soaking the pyrolysis product by hydrochloric acid solution, was proposed to optimize the graphitization degree, morphology, specific area, and pore size distribution of the products. The tests results demonstrated that the PC product obtained by a modified template method (M-TC) exhibited a transformation in microstructure such as an enhanced specific surface area and more plentiful hierarchical pores as compared with those PC materials obtained by conventional strategy. The potential formation mechanisms are proposed as well. When the M-TC sample loaded sulfur was applied as a cathode material for a Li-S battery, it delivered a high initial discharge capacity (1475 mAh g−1) and a stable discharge capacity (874 mAh g−1) after 50 cycles at 0.1 C. The modified template-removal strategy could bring inspirations on synthesis design and extend potential applications of commercial PC materials
Process optimization for producing hierarchical porous bamboo-derived carbon materials with ultrahigh specific surface area for lithium-sulfur batteries
No full textBamboo derived porous carbon materials, as inexpensive and environmentally friendly, microporous material sources, have been attracting enthusiastic attention for energy storage applications. In this work three different processes were employed to prepare three types of bamboo derived porous carbon materials. Among them, the sample prepared via a one-step activation method delivered the largest total pore volume (1.146 cm3 g−1) and the largest specific surface area (1824.4 m2 g−1) owning to a hierarchical porous structure. After the sample was used to encapsulate sulfur (S) to prepare carbon/S composite as cathodes for Li-S batteries. The composite loaded with 58.5 wt% S exhibited a high initial capacity of 1453 mAh g−1 at a rate of 0.1 C (1 C = 1675 mA g−1). A reversible capacity of 255 mAh g−1 was maintained after 500 cycles at 1 C with a capacity decay rate of only 0.0016% per cycle. This suggests that the bamboo derived porous carbon could be a promising conductive carbon matrix for carbon/S composite cathodes in Li–S batteries
Underexplored Dimensions of Emerging Indoor Photovoltaics
No full textIndoor photovoltaics (IPVs) can significantly reduce reliance on disposable batteries in Internet of Things (IoT) devices. Yet, most evaluations use idealized lighting setups and single performance metrics, neglecting the influence of real indoor environments on device performance. This Perspective advances a deployment-centered approach: (i) realistic testing under mixed or hybrid lighting (daylight + artificial); (ii) intelligent integration that aligns absorber bandgap, series-connected cells, geometric fill factor, and power management integrated circuits with workloads and duty cycles; and (iii) IoT-ready stability assessed under the same realistic indoor scenes and light/dark sequences. We propose a compact field-to-lab pipeline, translate it into voltage-matching design rules, and use photon-to-compute metrics to link harvested power to on-device sensing and learning. The goal is low-maintenance, battery-free nodes that scale reliably in buildings, logistics, and wearable applications─ultimately cutting electronic waste
Light Power Resource Variability for Energy Harvesting Photovoltaics for Self-Powered IoT
No full textFull Thermoelectric Characterization of Stoichiometric Electrodeposited Thin Film Tin Selenide (SnSe)
No full textTin selenide (SnSe) has attracted much attention in the thermoelectric community since the discovery of the record figure of merit (ZT) of 2.6 in single crystal tin selenide in 2014. There have been many reports since of the thermoelectric characterization of SnSe synthesized or manufactured by several methods, but so far none of these have concerned the electrodeposition of SnSe. In this work, stoichiometric SnSe was successfully electrodeposited at −0.50 V vs SCE as shown by EDX, XPS, UPS, and XRD. The full ZT of the electrodeposits were then measured. This was done by both a delamination technique to measure the Seebeck coefficient and electrical conductivity which showed a peak power factor of 4.2 and 5.8 μW m–1 K–2 for the as deposited and heat-treated films, respectively. A novel modified transient 3ω method was used to measure the thermal conductivity of the deposited films on the deposition substrate. This revealed the thermal conductivity to be similar to the ultralow thermal conductivity of single crystal SnSe, with a value of 0.34 W m–1 K–1 being observed at 313 K
Electrochemical Characterization of the UV-Photodegradation of Dye-Sensitized Solar Cells and Usage in the Assessment of UV-Protection Measures
No full textIdentifying recombination mechanisms through materials development in perovskite solar cells
No full textUtilizing Optoelectronic Characterization Techniques in the Development of Triple Mesoporous Perovskite Solar Cells
No full textElectrochemical Analysis for the Realization of Low Temperature Processed ZnO Dye-Sensitized Solar Cells
No full textUV Filtering of Dye-Sensitized Solar Cells: The Effects of Varying the UV Cut-Off upon Cell Performance and Incident Photon-to-Electron Conversion Efficiency
No full textWith current technology, UV filters are essential to ensure long-term dye-sensitized solar cell (DSC) stability. Blocking photons, however, will have an obvious effect on device performance and upon its incident photon-to-current conversion efficiency (IPCE). Filters have been applied to DSC devices with a range of cut-off wavelengths in order to assess how different levels of filtering affect the performance and IPCE of devices made with three different dyes, namely N719, Z907, and N749. It is shown that dyes that extend their IPCE further into the NIR region suffer lesser relative efficiency losses due to UV filtering than dyes with narrower action spectra. Furthermore, the results are encouraging to those working towards the industrialisation of DSC technology. From the results presented it can be estimated that filtering at a level intended to prevent direct band gap excitation of the TiO2 semiconductor should cause a relative drop in cell efficiency of no more than 10% in forward illuminated devices and no more than 2% in reverse illuminated devices
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