The necessity for new sources for greener and cleaner energy production to replace the existing ones has been increasingly growing in recent years. Of those new sources, the hydrogen evolution ...reaction has a large potential. In this work, for the first time, MoSe2/Mo core–shell 3D‐hierarchical nanostructures are created, which are derived from the Mo 3D‐hierarchical nanostructures through a low‐temperature plasma‐assisted selenization process with controlled shapes grown by a glancing angle deposition system.
The formation of PtSe2‐layered films is reported in a large area by the direct plasma‐assisted selenization of Pt films at a low temperature, where temperatures, as low as 100 °C at the applied ...plasma power of 400 W can be achieved. As the thickness of the Pt film exceeds 5 nm, the PtSe2‐layered film (five monolayers) exhibits a metallic behavior. A clear p‐type semiconducting behavior of the PtSe2‐layered film (≈trilayers) is observed with the average field effective mobility of 0.7 cm2 V−1 s−1 from back‐gated transistor measurements as the thickness of the Pt film reaches below 2.5 nm. A full PtSe2 field effect transistor is demonstrated where the thinner PtSe2, exhibiting a semiconducting behavior, is used as the channel material, and the thicker PtSe2, exhibiting a metallic behavior, is used as an electrode, yielding an ohmic contact. Furthermore, photodetectors using a few PtSe2‐layered films as an adsorption layer synthesized at the low temperature on a flexible substrate exhibit a wide range of absorption and photoresponse with the highest photocurrent of 9 µA under the laser wavelength of 408 nm. In addition, the device can maintain a high photoresponse under a large bending stress and 1000 bending cycles.
Phase‐engineered PtSe2‐layered films by a plasma‐assisted selenization process to highly sensitive, flexible, and wide‐spectrum photoresponse photodetectors are demonstrated. A full PtSe2 field effect transistor is also demonstrated where the thinner PtSe2, exhibiting a semiconducting behavior, is used as the channel material, and the thicker PtSe2, exhibiting a metallic behavior, is used as an electrode.
In this work, polymethylmethacrylate (PMMA) as a superior mediate for the pressure welding of silver nanowires (Ag NWs) networks as transparent electrodes without any thermal treatment is ...demonstrated. After a pressing of 200 kg cm−2, not only the sheet resistance but also the surface roughness of the PMMA‐mediated Ag NWs networks decreases from 2.6 kΩ sq−1 to 34.3 Ω sq−1 and from 76.1 to 12.6 nm, respectively. On the other hand, high transparency of an average transmittance in the visible wavelengths of 93.5% together with a low haze value of 2.58% can be achieved. In terms of optoelectronic applications, the promising potential of the PMMA‐mediated pressure‐welded Ag NWs networks used as a transparent electrode in a green organic light‐emitting diode (OLED) device is also demonstrated. In comparison with the OLED based on commercial tin‐doped indium oxide electrode, the increments of power efficiency and external quantum efficiency (EQE) from 80.1 to 85.9 lm w−1 and 19.2% to 19.9% are demonstrated. In addition, the PMMA‐mediated pressure welding succeeds in transferring Ag NWs networks to flexible polyethylene naphthalate and polyimide substrates with the sheet resistance of 42 and 91 Ω sq−1 after 10 000 times of bending, respectively.
An efficient room‐temperature pressure welding technique to fabricate the silver nanowires networks/polymethylmethacrylate composite transparent electrode is reported and demonstrated. In comparison with the organic light‐emitting diode based on commercial tin‐doped indium oxide electrode, the increments of power efficiency and external quantum efficiency from 80.1 to 85.9 lm w−1 and 19.2% to 19.9% are demonstrated.
Phase‐engineered type‐II metal–selenide heterostructures are demonstrated by directly selenizing indium‐tin oxide to form multimetal selenides in a single step. The utilization of a plasma system to ...assist the selenization facilitates a low‐temperature process, which results in large‐area films with high uniformity. Compared to single‐metal–selenide‐based photodetectors, the multimetal–selenide photodetectors exhibit obviously improved performance, which can be attributed to the Schottky contact at the interface for tuning the carrier transport, as well as the type‐II heterostructure that is beneficial for the separation of the electron–hole pairs. The multimetal–selenide photodetectors exhibit a response to light over a broad spectrum from UV to visible light with a high responsivity of 0.8 A W−1 and an on/off current ratio of up to 102. Interestingly, all‐transparent photodetectors are successfully produced in this work. Moreover, the possibility of fabricating devices on flexible substrates is also demonstrated with sustainable performance, high strain tolerance, and high durability during bending tests.
Phase‐engineered type‐II metal–selenide heterostructures are demonstrated by directly selenizing indium‐tin oxide to form multimetal selenides in a single step. The multimetal–selenide photodetectors exhibit obviously improved performance, which can be attributed to the Schottky contact at the interface for tuning the carrier transport, as well as the type‐II heterostructure that is beneficial for the separation of the electron–hole pairs.
Three-dimensional (3D) CuO/TiO
2
hybrid heterostructure nanorod arrays (NRs) with noble-metal-free composition, fabricated by template-assisted low-cost processes, were used as the photo-Fenton-like ...catalyst for dye degradation. Here, CuO NRs were deposited into anodic aluminum oxide templates by electrodeposition method annealed at various temperatures, followed by deposition of TiO
2
thin films through E-gun evaporation, resulting in the formation of CuO/TiO
2
p-n heterojunction. The distribution of elements and compositions of the CuO/TiO
2
p-n heterojunction were analyzed by EDS mapping and EELS profiles, respectively. In the presence of H
2
O
2
, CuO/TiO
2
hybrid structure performed more efficiently than CuO NRs for Rhodamine B degradation under the irradiation of 500-W mercury-xenon arc lamp. This study demonstrated the effect of length of CuO NRs, on the photo-degradation performance of CuO NRs as well as CuO/TiO
2
heterostructure. The optimized CuO/TiO
2
hybrid NR array structure exhibited the highest photo-degradation activity, and the mechanism and role of photo-Fenton acting as the catalyst in photo-degradation of dye was also investigated.
Selenium (Se) is one of the potential candidates as photodetector because of its outstanding properties such as high photoconductivity (∼8 × 104 S cm–1), piezoelectricity, thermoelectricity, and ...nonlinear optical responses. Solution phase synthesis becomes an efficient way to produce Se, but a contamination issue that could deteriorate the electric characteristic of Se should be taken into account. In this work, a facile, controllable approach of synthesizing Se nanowires (NWs)/films via a plasma-assisted growth process was demonstrated at the low substrate temperature of 100 °C. The detailed formation mechanisms of nanowires arrays to thin films at different plasma powers were investigated. Moreover, indium (In) layer was used to enhance the adhesive strength with 50% improvement on a SiO2/Si substrate by mechanical interlocking and surface alloying between Se and In layers, indicating great tolerance for mechanical stress for future wearable devices applications. Furthermore, the direct growth of Se NWs/films on a poly(ethylene terephthalate) substrate was demonstrated, exhibiting a visible to broad infrared detection ranges from 405 to 1555 nm with a high on/off ratio of ∼700 as well as the fast response time less than 25 ms. In addition, the devices exhibited fascinating stability in the atmosphere over one month.
In this work, for the first time, the addition of aluminum oxide nanostructures (Al2O3 NSs) grown by glancing angle deposition (GLAD) is investigated on an ultrathin Cu(In,Ga)Se2 device (400 nm) ...fabricated using a sequential process, i.e., post‐selenization of the metallic precursor layer. The most striking observation to emerge from this study is the alleviation of phase separation after adding the Al2O3 NSs with improved Se diffusion into the non‐uniformed metallic precursor due to the surface roughness resulting from the Al2O3 NSs. In addition, the raised Na concentration at the rear surface can be attributed to the increased diffusion of Na ion facilitated by Al2O3 NSs. The coverage and thickness of the Al2O3 NSs significantly affects the cell performance because of an increase in shunt resistance associated with the formation of Na2SeX and phase separation. The passivation effect attributed to the Al2O3 NSs is well studied using the bias‐EQE measurement and J–V characteristics under dark and illuminated conditions. With the optimization of the Al2O3 NSs, the remarkable enhancement in the cell performance occurs, exhibiting a power conversion efficiency increase from 2.83% to 5.33%, demonstrating a promising method for improving ultrathin Cu(In,Ga)Se2 devices, and providing significant opportunities for further applications.
The self‐assembled Al2O3 nanostructure (NS) prepared by glancing angle deposition and placed at the rear surface of the ultrathin Cu(In,Ga)Se2 film fabricated using the sequential process has been demonstrated. A uniformly Ga‐distributed and rear‐passivated absorber is achieved for the Cu(In,Ga)Se2 film with Al2O3 NS, yielding an increase in cell efficiency from 2.83% to 5.33%.
In this work, three-dimensional (3D) CoMoSe
4
nanosheet arrays on network fibers of a carbon cloth denoted as CoMoSe
4
@C converted directly from CoMoO
4
nanosheet arrays prepared by a hydrothermal ...process followed by the plasma-assisted selenization at a low temperature of 450 °C as an anode for sodium-ion battery (SIB) were demonstrated for the first time. With the plasma-assisted treatment on the selenization process, oxygen (O) atoms can be replaced by selenium (Se) atoms without the degradation on morphology at a low selenization temperature of 450 °C. Owing to the high specific surface area from the well-defined 3D structure, high electron conductivity, and bi-metal electrochemical activity, the superior performance with a large sodium-ion storage of 475 mA h g
−1
under 0.5–3 V potential range at 0.1 A g
−1
was accomplished by using this CoMoSe
4
@C as the electrode. Additionally, the capacity retention was well maintained over 80 % from the second cycle, exhibiting a satisfied capacity of 301 mA h g
−1
even after 50 cycles. The work delivered a new approach to prepare a binary transition metallic selenide and definitely enriches the possibilities for promising anode materials in SIBs with high performances.
Abstract
Hierarchically ordered structures with low tortuosity, excellent mechanical flexibility, high optical transparency, and outstanding electrical conductivity are critically important in ...developing flexible transparent supercapacitor electrodes for innovative applications in electronics and displays. Here a CVD process is employed to fabricate leaf-skeleton inspired electrodes, which are reticulated monolithic networks consisting of carbon nanostructures serving as a 3D spongy core and graphene-based films as a protective/conductive shell. The network electrodes show optical transmittance of 85–88%, an electrical sheet resistance of ~1.8 Ω/sq, and an areal capacitance of 7.06 mF cm
−2
(at 0.78 mA cm
−2
in a three-electrode cell) in Na
2
SO
4
aqueous electrolyte. Flexible transparent and symmetric supercapacitors, based on PVA/H
3
PO
4
gel and the network electrodes, possess a stable working voltage of 1.6 V, energy and power density of 0.068 μWh cm
−2
and 47.08 μW cm
−2
at an optical transparency of ~80%, and no capacitance loss over 30,000 flat-bend-release cycles.
Transition metal dichalcogenides (TMDCs) have recently attracted a tremendous amount of attention owing to their superior optical and electrical properties as well as the interesting and various ...nanostructures that are created by different synthesis processes. However, the atomic thickness of TMDCs limits the light absorption and results in the weak performance of optoelectronic devices, such as photodetectors. Here, we demonstrate the approach to increase the surface area of TMDCs by a one-step synthesis process of TMDC nanowalls from WO x into three-dimensional (3D) WS2 nanowalls. By utilizing a rapid heating and rapid cooling process, the formation of 3D nanowalls with a height of approximately 150 nm standing perpendicularly on top of the substrate can be achieved. The combination of core–shell colloidal quantum dots (QDs) with three different emission wavelengths and 3D WS2 nanowalls further improves the performance of WS2-based photodetector devices, including a photocurrent enhancement of 320–470% and shorter response time. The significant results of the core–shell QD–WS2 hybrid devices can be contributed by the high nonradiative energy transfer efficiency between core–shell QDs and the nanostructured material, which is caused by the spectral overlap between the emission of core–shell QDs and the absorption of WS2. Besides, outstanding NO2 gas-sensing performance of core–shell QDs/WS2 devices can be achieved with an extremely low detection limit of 50 ppb and a fast response time of 26.8 s because of local p–n junctions generated by p-type 3D WS2 nanowalls and n-type core–shell CdSe-ZnS QDs. Our work successfully reveals the energy transfer phenomenon in core–shell QD–WS2 hybrid devices and shows great potential in commercial multifunctional sensing applications.
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