The developments of rationally designed binder‐free metal chalcogenides decorated flexible electrodes are of paramount importance for advanced energy storage devices. Herein, binder‐free patronite ...(VS4) flower‐like nanostructures are facilely fabricated on a carbon cloth (CC) using a facile hydrothermal method for high‐performance supercapacitors. The growth density and morphology of VS4 nanostructures on CC are also controlled by varying the concentrations of vanadium and sulfur sources along with the complexing agent in the growth solution. The optimal electrode with an appropriate growth concentration (VS4‐CC@VS‐3) demonstrates a considerable pseudocapacitance performance in the ionic liquid (IL) electrolyte (1‐ethyl‐3‐methylimidazolium trifluoromethanesulfonate), with a high operating potential of 2 V. Utilizing VS4‐CC@VS‐3 as both positive and negative electrodes, the IL‐based symmetric supercapacitor is assembled, which demonstrates a high areal capacitance of 536 mF cm−2 (206 F g−1) and excellent cycling durability (93%) with superior energy and power densities of 74.4 µWh cm−2 (28.6 Wh kg−1) and 10154 µW cm−2 (9340 W kg−1), respectively. As for the high energy storage performance, the device stably energizes various portable electronic applications for a long time, which make the fabricated composite material open up news for the fabrication of fabrics supported binder‐free chalcogenides for high‐performance energy storage devices.
A selective synthesis of binder‐free patronite (VS4) flower‐like nanostructures on carbon cloth is successfully designed for a pseudocapacitor electrode. This electrode in ionic liquid electrolyte demonstrates enhanced working potential to provide superior energy and power densities for practical applications.
Transition metal oxides (TMOs) have recently been proved to efficiently serve as hole-selective contacts in crystalline silicon (c-Si) heterojunction solar cells. In the present work, two TMO/c-Si ...heterojunctions are explored using MoO3 (reference) and V2O5 as an alternative candidate. It has been found that V2O5 devices present larger (16% improvement) power conversion efficiency mainly due to their higher open-circuit voltage. While V2O5/c-Si devices with textured front surfaces exhibit larger short-circuit currents, it is also observed that flat solar cell architectures allow for passivation of the V2O5/n-Si interface, giving significant carrier lifetimes of 200 μs (equivalent to a surface recombination velocity of Seff ~140cms−1) as derived from impedance analysis. As a consequence, a significant open-circuit voltage of 662mV is achieved. It is found that, at the TMO/c-Si contact, a TMO work function enhancement ΔΦTMO occurs during the heterojunction formation with the consequent dipole layer enlargement Δ’=Δ+ΔΦTMO. Our results provide new insights into the TMO/c-Si contact energetics, carrier transport across the interface and surface recombination allowing for further understanding of the nature of TMO/c-Si heterojunctions.
•TMOs are proved as hole-selective contacts in silicon heterojunction solar cells.•V2O5 devices present 16% improvement in conversion efficiency compared to MoO3.•‐1V2O5/n-Si allows for carrier lifetime of 200 ms (Seff ~140 cm s-1).
Electronic properties of Au/V2O5/n-Si Schottky device have been investigated by temperature dependent current–voltage (I–V) and capacitance–voltage (C–V) measurements ranging from 300 K to 150 K. ...Ideality factor (n) and barrier height (ϕ) for the Schottky device were obtained from I–V characteristics as 2.04 and 0.83 eV at 300 K and 6.95 and 0.39 eV at 150 K respectively. It was observed that in presence of inhomogeneity at metal–semiconductor interface, the ideality factor increases and barrier height decreases with the decrease of temperature. The Richardson constant value was estimated as 137 A–cm−2–K−2 from modified Richardson plot, which is closer to the known theoretical value of n-Si where mean value of barrier height
(
ϕ
b
0
¯
)
, and its standard deviation (σ
0
) were estimated using double Gaussian distribution (DGD) analysis. Different device parameters, namely, built-in potential, carrier concentration, image force lowering and depletion width were also obtained from the C–V–T measurements. First time use of V2O5 thin-film as an interfacial layer (IL) on Au/V2O5/n-Si Schottky diode was successfully explained by the thermionic emission (TE) theory. The interesting result obtained in this present work is the V2O5 thin-film reduced its conducting capability with decreasing temperature, while it shows a totally insulating behaviour below 150 K.
Ladder-type molecules, which possess an extended aromatic backbone, are particularly sought within the optoelectronic field. In view of the potential of the 14
-bis1benzothieno3,2-
:2',3'-
carbazole ...core as a p-type semiconductor, herein we studied a set of two derivatives featuring a different alkylation patterning. The followed synthetic route, involving various sulfurated carbazole-based molecules, also resulted in a source of fluorophores with different emitting behaviors. Surprisingly, the sulfoxide-containing fluorophores substantially increased their blue fluorescence with respect to the nearly non-emitting sulfur counterparts. On this basis, we could shed light on the relationship between their chemical structure and their emission as an approach for future applications. Considering the performance in organic thin-film transistors, both bisbenzothienocarbazole derivatives displayed p-type characteristics, with hole mobility values up to 1.1 × 10
cm
V
s
and considerable air stability. Moreover, the role of the structural design has been correlated with the device performance by means of X-ray analysis and the elucidation of the corresponding single crystal structures.
Temperature dependent current–voltage (I‒V) characteristics of Au/n-type silicon (n-Si) Schottky barrier diodes have been investigated. Three transition metal oxides (TMO) are used as an interface ...layer between gold and silicon. The basic Schottky diode parameters such as ideality factor (n), barrier height (ϕb0) and series resistance (Rs) are calculated and successfully explained by the thermionic emission (TE) theory. It has been found that ideality factor decreased and barrier height increased with increased of temperature. The conventional Richardson plot of ln(I0/T2) vs. 1000/T is determined the activation energy (Ea) and Richardson constant (A*). Whereas value of ‘A*’ is much smaller than the known theoretical value of n-type Si. The temperature dependent I–V characteristics obtained the mean value of barrier height (ϕb0¯) and standard deviation (σs) from the linear plot of ϕap vs. 1000/T. From the modified Richardson plot of ln(I0/T2) ˗ (qσ)2/2(kT)2 vs. 1000/T gives Richardson constant and homogeneous barrier height of Schottky diodes. Main observation in this present work is the barrier height and ideality factor shows a considerable change but the series resistance value exhibits negligible change due to TMO as an interface layer.
•Three different transition metal oxides are used as an interface layer in Au/n-Si SBDs.•Barrier height and ideality factor shows a considerable enhancement with the use of TMO.•The negligible changes of series resistance due to TMO.•Inhomogeneity increased in presence of TMO between gold and silicon.
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