Rujia Zou

Hydrophilic Cu9S5 Nanocrystals: A Photothermal Agent with a 25.7% Heat Conversion Efficiency for Photothermal Ablation of Cancer Cells in Vivo

Photothermal ablation (PTA) therapy has a great potential to revolutionize conventional therapeutic approaches for cancers, but it has been limited by difficulties in obtaining biocompatible photothermal agents that have low cost, small size (<100 nm), and high photothermal conversion efficiency. Herein, we have developed hydrophilic plate-like Cu(9)S(5) nanocrystals (NCs, a mean size of ∼70 nm × 13 nm) as a new photothermal agent, which are synthesized by combining a thermal decomposition and ligand exchange route. The aqueous dispersion of as-synthesized Cu(9)S(5) NCs exhibits an enhanced absorption (e.g., ∼1.2 × 10(9) M(-1) cm(-1) at 980 nm) with the increase of wavelength in near-infrared (NIR) region, which should be attributed to localized surface plasmon resonances (SPR) arising from p-type carriers. The exposure of the aqueous dispersion of Cu(9)S(5) NCs (40 ppm) to 980 nm laser with a power density of 0.51 W/cm(2) can elevate its temperature by 15.1 °C in 7 min; a 980 nm laser heat conversion efficiency reaches as high as 25.7%, which is higher than that of the as-synthesized Au nanorods (23.7% from 980 nm laser) and the recently reported Cu(2-x)Se NCs (22% from 808 nm laser). Importantly, under the irradiation of 980 nm laser with the conservative and safe power density over a short period (∼10 min), cancer cells in vivo can be efficiently killed by the photothermal effects of the Cu(9)S(5) NCs. The present finding demonstrates the promising application of the Cu(9)S(5) NCs as an ideal photothermal agent in the PTA of in vivo tumor tissues.

Hydrophilic Flower‐Like CuS Superstructures as an Efficient 980 nm Laser‐Driven Photothermal Agent for Ablation of Cancer Cells

Photothermal ablation (PTA) therapy has attracted much interest in recent years as a minimally invasive alternative to conventional approaches, such as surgery and chemotherapy, for therapeutic intervention of specifi c biological targets. [ 1 , 2 ] In particular, near-infrared (NIR, λ = 700–1100 nm) laser-induced PTA, which converts NIR optical energy into thermal energy, has attracted increasing attention, because the NIR laser is absorbed less by biological tissues and the typical penetration depth of the NIR (such as 980 nm) light can be several centimeters in biological tissues. [ 3 , 4 ] A prerequisite for the development of the NIR laser-induced PTA is to gain access to biocompatible and effi cient photothermal coupling agents. As the well-known NIR photothermal conversion agents, gold (Au) nanostructures, including supramolecularly assembled nanoparticles, [ 5–8 ]

Sub-10 nm Fe3O4@Cu2–xS Core–Shell Nanoparticles for Dual-Modal Imaging and Photothermal Therapy

Photothermal nanomaterials have recently attracted significant research interest due to their potential applications in biological imaging and therapeutics. However, the development of small-sized photothermal nanomaterials with high thermal stability remains a formidable challenge. Here, we report the rational design and synthesis of ultrasmall (<10 nm) Fe3O4@Cu2-xS core-shell nanoparticles, which offer both high photothermal stability and superparamagnetic properties. Specifically, these core-shell nanoparticles have proven effective as probes for T2-weighted magnetic resonance imaging and infrared thermal imaging because of their strong absorption at the near-infrared region centered around 960 nm. Importantly, the photothermal effect of the nanoparticles can be precisely controlled by varying the Cu content in the core-shell structure. Furthermore, we demonstrate in vitro and in vivo photothermal ablation of cancer cells using these multifunctional nanoparticles. The results should provide improved understanding of synergistic effect resulting from the integration of magnetism with photothermal phenomenon, important for developing multimode nanoparticle probes for biomedical applications.

Hierarchical mesoporous NiCo2O4@MnO2 core–shell nanowire arrays on nickel foam for aqueous asymmetric supercapacitors

We demonstrate the design and fabrication of hierarchical mesoporous NiCo2O4@MnO2 core–shell nanowire arrays on nickel foam via a facile hydrothermal and electrodeposition process for supercapacitor applications. In order to increase the energy density and voltage window, a high-voltage asymmetric supercapacitor based on hierarchical mesoporous NiCo2O4@MnO2 core–shell nanowire arrays on nickel foam as the positive electrode and activated carbon (AC) as the negative electrode was successfully fabricated. The as-fabricated asymmetric supercapacitor device achieved a specific capacitance of 112 F g−1 at a current density of 1 mA cm−2 with a stable operational voltage of 1.5 V and a maximum energy density of 35 W h kg−1. The present NiCo2O4@MnO2 core–shell nanowire arrays with remarkable electrochemical properties could be considered as potential electrode materials for next generation supercapacitors in high energy density storage systems.

Chain-like NiCo2O4 nanowires with different exposed reactive planes for high-performance supercapacitors

Faceted crystals with different exposed planes have attracted intensive investigations for applications. Herein, we report a facile hydrothermal and thermal decomposition process which is successfully developed to grow 3D NiCo2O4 micro-spheres constructed with radial chain-like NiCo2O4 nanowires with different exposed crystal planes. When applied as electrode materials for supercapacitors, chain-like NiCo2O4 nanowires exhibit excellent electrochemical performances in supercapacitors with high specific capacitance (1284 F g−1 at 2 A g−1), good rate capability, and excellent cycling stability (only 2.5% loss after 3000 cycles). In situ electrical properties clearly illustrated that the chain-like nanowires with different exposed crystal planes exhibit excellent electronic conductivity, which shows that the electronic conductivity plays an essential role for electrode materials in supercapacitors. So, high electronic conductivity chain-like NiCo2O4 nanowires with different exposed crystal planes can form a competitive electrode material for next generation supercapacitors.

Highly aligned SnO2 nanorods on graphene sheets for gas sensors

Highly aligned SnO2 nanorods on graphene 3-D array structures were synthesized by a straightforward nanocrystal-seeds-directing hydrothermal method. The diameter and density of the nanorods grown on the graphene can be easily tuned as required by varying the seeding concentration and temperature. The array structures were used as gas sensors and exhibit improved sensing performances to a series of gases in comparison to that of SnO2 nanorod flowers. For nanorod arrays of optimal diameter and distribution, these structures were proved to exert an enhanced sensitivity to reductive gases (especially H2S), which was twice as high as that obtained using SnO2 nanorod flowers. The improved sensing properties are attributed to the synergism of the large surface area of SnO2 nanorod arrays and the superior electronic characteristics of graphene.

Hydrophilic Cu2ZnSnS4 nanocrystals for printing flexible, low-cost and environmentally friendly solar cells

Using Cu2ZnSnS4 (CZTS) nanocrystal-based ink (via a solvothermal route) and roll-to-roll printing, CZTS films are prepared on a Mo-coated Al foil, and then flexible solar cells with a structure of Al foil/Mo/CZTS/ZnS/i-ZnO/ITO/Al–Ni and a power conversion efficiency of 1.94% are constructed, in which all the materials are low-cost and environmentally friendly.

MnO2 ultralong nanowires with better electrical conductivity and enhanced supercapacitor performances

Single-crystal α-MnO2 ultralong nanowires (∼40 μm in length, ∼15 nm in diameter), which were synthesized by a simple polyvinylpyrrolidone (PVP) assisted hydrothermal route, exhibited a better electrical conductivity, a highest specific capacitance of 345 F g−1 at a current density of 1 A g−1 with high rate capability (54.7% at 10 A g−1) and good cycling stability.

Facile synthesis of porous MnCo2O4.5 hierarchical architectures for high- rate supercapacitors

Porous urchin-like MnCo2O4.5 hierarchical architectures (~4–6 μm in diameter) synthesized by a facile hydrothermal route followed by a calcination process exhibited a specific capacitance of 151.2 F g−1 at 5 mV s−1, outstanding rate capability with 83.6% specific capacitance retention even when the current density is increased 50 times and excellent long-term cycle stability at progressively varied current densities and could be considered as a potential mixed transition metal oxide material for high-rate supercapacitors in some special applications that do not require a high capacitance.

Self-assembling hybrid NiO/Co3O4 ultrathin and mesoporous nanosheets into flower-like architectures for pseudocapacitance

The rational design and synthesis of mesoporous hybrid architecture electrode materials for high-performance pseudocapacitor applications still remains a challenge. Herein, we demonstrate the design and fabrication of hybrid NiO/Co3O4 flower-like mesoporous architectures on a large-scale for high-performance supercapacitors by a facile, environmentally friendly, and low-cost synthetic method. The as-synthesized hybrid NiO/Co3O4 flower-like architectures show a high specific capacitance of 1068 F g−1 at a scan rate of 5 mV s−1 and 1190 F g−1 at a current density of 4 A g−1, a good rate capability even at high current densities and an excellent long-term cycling stability (less than 1% loss of the maximum specific capacitance after 5000 cycles), which can be mainly attributed to their morphological characteristics of mesoporous and ultrathin nanosheets self-assembling into flower-like architectures, as well as a rational composition of the two constituents. The remarkable electrochemical properties, as well as many advantages associated with the synthetic method, should make the present architectures competitive electrode materials for next generation supercapacitors.