3 research outputs found
Photoresponse of a Single Y‑Junction Carbon Nanotube
We report investigation of optical
response in a single strand of a branched carbon nanotube (CNT), a
Y-junction CNT composed of multiwalled CNTs. The experiment was performed
by connecting a pair of branches while grounding the remaining one.
Of the three branch combinations, only one combination is optically
active which also shows a nonlinear semiconductor-like <i>I</i>–<i>V</i> curve, while the other two branch combinations
are optically inactive and show linear ohmic <i>I</i>–<i>V</i> curves. The photoresponse includes a zero-bias photocurrent
from the active branch combination. Responsivity of ≈1.6 mA/W
has been observed from a single Y-CNT at a moderate bias of 150 mV
with an illumination of wavelength 488 nm. The photoresponse experiment
allows us to understand the nature of internal connections in the
Y-CNT. Analysis of data locates the region of photoactivity at the
junction of only two branches and only the combination of these two
branches (and not individual branches) exhibits photoresponse upon
illumination. A model calculation based on back-to-back Schottky-type
junctions at the branch connection explains the <i>I</i>–<i>V</i> data in the dark and shows that under
illumination the barriers at the contacts become lowered due to the
presence of photogenerated carriers
Solution-Processed CoFe<sub>2</sub>O<sub>4</sub> Nanoparticles on 3D Carbon Fiber Papers for Durable Oxygen Evolution Reaction
We report CoFe<sub>2</sub>O<sub>4</sub> nanoparticles (NPs) synthesized using a facile hydrothermal growth
and their attachment on 3D carbon fiber papers (CFPs) for efficient
and durable oxygen evolution reaction (OER). The CFPs covered with
CoFe<sub>2</sub>O<sub>4</sub> NPs show orders of magnitude higher
OER performance than bare CFP due to high activity of CoFe<sub>2</sub>O<sub>4</sub> NPs, leading to a small overpotential of 378 mV to
get a current density of 10 mA/cm<sup>2</sup>. Significantly, the
CoFe<sub>2</sub>O<sub>4</sub> NPs-on-CFP electrodes exhibit remarkably
long stability evaluated by continuous cycling (over 15 h) and operation
with a high current density at a fixed potential (over 40 h) without
any morphological change and with preservation of all materials within
the electrode. Furthermore, the CoFe<sub>2</sub>O<sub>4</sub> NPs-on-CFP
electrodes also exhibit hydrogen evolution reaction (HER) performance,
which is considerably higher than that of bare CFP, acting as a bifunctional
electrocatalyst. The achieved results show promising potential for
efficient, cost-effective, and durable hydrogen generation at large
scales using earth-abundant materials and cheap fabrication processes
Solution-Processed CoFe<sub>2</sub>O<sub>4</sub> Nanoparticles on 3D Carbon Fiber Papers for Durable Oxygen Evolution Reaction
We report CoFe<sub>2</sub>O<sub>4</sub> nanoparticles (NPs) synthesized using a facile hydrothermal growth
and their attachment on 3D carbon fiber papers (CFPs) for efficient
and durable oxygen evolution reaction (OER). The CFPs covered with
CoFe<sub>2</sub>O<sub>4</sub> NPs show orders of magnitude higher
OER performance than bare CFP due to high activity of CoFe<sub>2</sub>O<sub>4</sub> NPs, leading to a small overpotential of 378 mV to
get a current density of 10 mA/cm<sup>2</sup>. Significantly, the
CoFe<sub>2</sub>O<sub>4</sub> NPs-on-CFP electrodes exhibit remarkably
long stability evaluated by continuous cycling (over 15 h) and operation
with a high current density at a fixed potential (over 40 h) without
any morphological change and with preservation of all materials within
the electrode. Furthermore, the CoFe<sub>2</sub>O<sub>4</sub> NPs-on-CFP
electrodes also exhibit hydrogen evolution reaction (HER) performance,
which is considerably higher than that of bare CFP, acting as a bifunctional
electrocatalyst. The achieved results show promising potential for
efficient, cost-effective, and durable hydrogen generation at large
scales using earth-abundant materials and cheap fabrication processes