Abstract:CuO nanomaterials are one of the metal-oxides that received extensive investigations in recent years due to their versatility for applications in high-performance nano-devices. Tailoring the device performance through the engineering of properties in the CuO nanomaterials thus attracted lots of effort. In this paper, we show that nanosecond (ns) laser irradiation is effective in improving the electrical and opto-electrical properties in the copper oxide nanowires (CuO NWs). We find that ns laser irradiation ca… Show more
“…Bandgap narrowing caused by defects in ZnO and other oxides can be attributed to optical transitions involving charge carriers trapped at energy levels within the bandgap [56,57]. These traps were verified and investigated by techniques such as photocurrent transients [23]. For instance, et al able to probe and determine these trap levels in ZnO using photocurrent transients under various light illuminations [58].…”
Section: Optical Propertiesmentioning
confidence: 99%
“…As the understanding of metal oxide nanomaterials has advanced, it is now recognized that point defects in metal oxide nanomaterials play a critical role in determining their optical, electrical and mechanical properties [16][17][18]. While conventional techniques such as high-temperature quenching are used for tuning the properties of metal oxide nanomaterials through the engineering of point defects [19,20], electron-beam irradiation [21,22] and laser irradiation [23,24] have emerged as two new techniques for defect engineering since they can be used to adjust and optimize the defect concentration at specific locations within the nanostructure.…”
Section: Introductionmentioning
confidence: 99%
“…The introduction of point defects through laser irradiation has been reported in both n and p-type metal oxide nanomaterials [23][24][25]. One major strategy produces point defects by exposing the metal oxide nanomaterials in liquid to pulsed laser irradiation [26,27].…”
In recent years, defect engineering has shown great potential to improve the properties of metal oxide nanomaterials for various applications thus received extensive investigations. While traditional techniques mostly focus on controlling the defects during the synthesis of the material, laser irradiation has emerged as a promising post-deposition technique to further modulate the properties of defects yet there is still limited information. In this article, defects such as oxygen vacancies are tailored in ZnO nanorods through nanosecond (ns) laser irradiation. The relation between laser parameters and the temperature rise in the ZnO due to laser heating was established based on the observation in the SEM and the simulation. Raman spectra indicated that the concentration of the oxygen vacancies in the ZnO is temperature-dependent and can be controlled by changing the laser fluence and exposure time. This is also supported by the absorption spectra and the photoluminescence spectra of ZnO NRs irradiated under these conditions. On the other hand, the distribution of the oxygen vacancies was studied by XPS depth profiling, and it was confirmed that the surface-to-bulk ratio of the oxygen vacancies can be modulated by varying the laser fluence and exposure time. Based on these results, four distinctive regimes containing different ratios of surface-to-bulk oxygen vacancies have been identified. Laser-processed ZnO nanorods were also used as the catalyst for the photocatalytic degradation of rhodamine B (RhB) dye to demonstrate the efficacy of this laser engineering technique.
“…Bandgap narrowing caused by defects in ZnO and other oxides can be attributed to optical transitions involving charge carriers trapped at energy levels within the bandgap [56,57]. These traps were verified and investigated by techniques such as photocurrent transients [23]. For instance, et al able to probe and determine these trap levels in ZnO using photocurrent transients under various light illuminations [58].…”
Section: Optical Propertiesmentioning
confidence: 99%
“…As the understanding of metal oxide nanomaterials has advanced, it is now recognized that point defects in metal oxide nanomaterials play a critical role in determining their optical, electrical and mechanical properties [16][17][18]. While conventional techniques such as high-temperature quenching are used for tuning the properties of metal oxide nanomaterials through the engineering of point defects [19,20], electron-beam irradiation [21,22] and laser irradiation [23,24] have emerged as two new techniques for defect engineering since they can be used to adjust and optimize the defect concentration at specific locations within the nanostructure.…”
Section: Introductionmentioning
confidence: 99%
“…The introduction of point defects through laser irradiation has been reported in both n and p-type metal oxide nanomaterials [23][24][25]. One major strategy produces point defects by exposing the metal oxide nanomaterials in liquid to pulsed laser irradiation [26,27].…”
In recent years, defect engineering has shown great potential to improve the properties of metal oxide nanomaterials for various applications thus received extensive investigations. While traditional techniques mostly focus on controlling the defects during the synthesis of the material, laser irradiation has emerged as a promising post-deposition technique to further modulate the properties of defects yet there is still limited information. In this article, defects such as oxygen vacancies are tailored in ZnO nanorods through nanosecond (ns) laser irradiation. The relation between laser parameters and the temperature rise in the ZnO due to laser heating was established based on the observation in the SEM and the simulation. Raman spectra indicated that the concentration of the oxygen vacancies in the ZnO is temperature-dependent and can be controlled by changing the laser fluence and exposure time. This is also supported by the absorption spectra and the photoluminescence spectra of ZnO NRs irradiated under these conditions. On the other hand, the distribution of the oxygen vacancies was studied by XPS depth profiling, and it was confirmed that the surface-to-bulk ratio of the oxygen vacancies can be modulated by varying the laser fluence and exposure time. Based on these results, four distinctive regimes containing different ratios of surface-to-bulk oxygen vacancies have been identified. Laser-processed ZnO nanorods were also used as the catalyst for the photocatalytic degradation of rhodamine B (RhB) dye to demonstrate the efficacy of this laser engineering technique.
“…Copperbased structures are popular candidates to use in flexible electronics due to the low cost of copper and its high electrical conductivity [13]. Furthermore, copper-based devices also garner interest due to the catalytic and semiconducting properties of copper oxides (Cu 2 O and CuO) [14][15][16]. For example, sintered copper-based flexible components with 808 nm laser have been successfully demonstrated as sensors [17,18], electrodes [11,19] and memory devices [20].…”
Rapid fabrication of flexible electronics is attracting much attention in many industries. There is a need for rapidly producing flexible electronic components without the reliance on costly precursor materials and complex processes. In this work, a direct laser writing process is presented as capable of rapidly depositing flexible copper or copper oxide structures with a high degree of control over electrical properties. The direct laser writing process uses a low-power fiber laser beam to selectively irradiate a thin film of copper ions to form and interconnect copper nanoparticles. The electrical properties of the deposited patterns can be controlled through tuning laser power, scanning speed, and beam defocus. The microstructures of patterns printed at varying laser powers are investigated using SEM, XPS, and XRD and the relation between laser power and sheet resistance is explored. The results showed that high laser energy densities resulted in highly conductive patterns of metallic copper, whereas lower energy patterns resulted in copper oxide rich patterns with significantly lower conductivity. This method can produce high-quality flexible electronic components with a range of potential applications, as demonstrated by the proof-of-concept fabrication of a flexible memristive junction with resistive switching observed at +/- 0.7V, and a Ron/Roff ratio of 10^2.
“…PTT can directly ablate tumors while assisting chemotherapy efficacy. − During last decades, various PTT agents have been widely explored, such as organic dyes (e.g., ICG , ), organic polymer nanoparticles (e.g., polyaniline , and polypyrrole , ), carbon-based nanomaterials (e.g., carbon nanotubes and graphene), − precious metal nanoparticles , and metallic chalcogenide nanomaterials . Among these materials, gold nanostructures (e.g., gold nanorods, nanoclusters, nanoflowers, nanocages, and nanoshells) − have become a research hotspot. In particular, gold nanorods (GNRs) are particularly attractive for simultaneous cancer treatment and diagnosis.…”
Combinatorial photothermal therapy and chemotherapy is an extremely promising tumor therapeutic modality. However, such systems still remain challenges in stimulus sensitivity, avoiding drug leakage, and therapeutic safety. To solve these problems, we engineered actively loaded doxorubicin (DOX) and gold nanorod (GNR) liposomes through embedding stiff hollow mesoporous silica nanoparticles (HMSNs) in the liposomal water cavity (HMLGDB) to resist the influence of shear force of GNRs to prevent drug leakage. Under 808 nm laser irradiation, the ambient temperature was raised greatly because of the photothermal conversion of GNRs, thereby rupturing the lipid layer and then triggering the DOX release. The results of in vitro experiments showed that the low concentration of HMLGDB (15 μg/mL) could effectively overcome the MCF-7 cells (human breast cancer cell line) by the increase of DOX concentration intracellularly and the good photothermal effect of GNRs. After intravenous injection, HMLGDB exhibited intratumor aggregation and PTT capacity. Furthermore, the combined chemo−photothermal antitumor strategy demonstrated a high inhibition of tumor growth and low damage to normal tissues. The developed hybrids provide a paradigm for efficient combinatorial photothermal therapy (PTT) and chemotherapy (CT).
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