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Poly(9-vinylcarbazole) (PVK) was introduced to modify the interface of perovskite/PCBM. The modified PVK material can induce the formation of the quasi-continuous sheet-shaped perovskite film at the surface of 3D perovskite layer, which may reduce the exposed grain boundaries. Besides, the PVK modified perovskite layer can reduce carrier recombination and accumulation at the interface of perovskite/PCBM and improve the crystallinity of perovskite layer and the interface contact properties. The PVK modification can greatly improve the PCEs and thermal and moisture stability and suppress the J-V hysteresis of perovskite solar cells (PSCs). PSCs with PVK modification achieved champion PCE of 19.03% (average PCE of 18.40%), maintained 80% of the original PCE value aging for 50 days under ambient conduction without encapsulation. Furthermore, PSCs with PVK modification can maintain 87% of the origin PCEs aging for 3 h under 85 °C thermal stress, which are greatly higher than that (26%) of PSCs without PVK modification.

We report a simple and low-cost approach to enhance the longstanding stability of the perovskite solar cell (PSC) through the application of low-temperature grown SnO2 nanorod (NR) arrays. SnO2 NR arrays were fabricated by an aqueous synthesis method in the presence of hydrochloric acid and using thin compact SnO2 as seeds. The influence of HCl concentration on the photovoltaic (PV) performance of the SnO2 NR array based PSC device was investigated. The formed crystalline SnO2 nanorods with square transversal-sections were oriented on the FTO facets in a well-defined and perpendicular fashion at an optimal HCl concentration. The optimized width and length for SnO2 nanorods were 30 nm and 150 nm, respectively. Consequently, efficient and stable SnO2 nanorod based perovskite devices were obtained with an average power conversion efficiency (PCE) of 16.57%. The SnO2 nanorod array based PSCs demonstrated considerably better ultraviolet (UV) and ambient air stability than the planar SnO2 and notably mesoporous TiO2 solar cells. This paper provides a prospective scheme to grow high-quality three-dimensional SnO2 nanorod arrays for highly stable and efficient PSCs.

MgFe2O4/reduced graphene oxide composites (MFO/RGO) were prepared via a facile microwave assisted reduction of graphene oxide in MFO precursor solution, and used as anode materials for sodium ion batteries (SIBs). Their morphology, structure and electrochemical performance were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption isotherms, galvanostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The results show that MFO/RGO composite with 20 wt.% RGO exhibits a maximum reversible capacity of about 347.5 mAh g−1 at 50 mA g−1 after 70 cycles with good cycling stability. The excellent electrochemical performance of MFO/RGO composites should be attributed to the synergistic effect of MFO and RGO to form a porous conductive network structure which offers the increased specific surface area, the facilitated electron transfer ability and the effective buffering of volume expansion.

GeO 2 -reduced graphene oxide (RGO) composites were prepared by a simple freeze-drying method. After thermal annealing in N 2 atmosphere at 450 °C for 2 hours, the composites were examined as anode materials of sodium ion batteries for the first time. Their morphology, structure and electrochemical performance were characterized by field-emission scanning electron microscopy, X-ray diffraction, N 2 adsorption-desorption isotherm, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. A maximum specific capacity of 330 mAh g −1 can be achieved after 50 galvanostatic charge-discharge cycles at a current density of 100 mA g −1 by tuning the RGO content in the composites. Even after 650 cycles at a high current density of 1 A g −1 , the specific capacity can still maintain at 153.7 mAh g −1 , demonstrating the excellent Na ion storage properties of the GeO 2 -RGO composites.

Fe 2 O 3 -reduced graphene oxide (RGO) composites were successfully fabricated via a facile microwave-assisted reduction of graphite oxide in Fe 2 O 3 precursor solution using a microwave system, and investigated as anode material for sodium ion batteries (SIBs). Their morphologies, structures and electrochemical performance were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The results show that the RGO addition can enhance the electrochemical performance of Fe 2 O 3 -RGO composites. Fe 2 O 3 -RGO composite with 30 wt.% RGO exhibits a maximum reversible capacity of 289 mA h g −1 at a current density of 50 mA g −1 after 50 cycles and excellent rate performance due to the synergistic effect between Fe 2 O 3 and RGO. The high capacity, good rate capability and excellent cycle performance of Fe 2 O 3 -RGO composites enable them a potential electrode material for SIBs.

Nitrogen-doped porous carbon spheres (NPCSs) were prepared through a fast microwave-assisted approach using sucrose as the precursor in a microwave system and subsequent thermal treatment in ammonia atmosphere at different temperatures. The morphology, structure and electrochemical performance of the NPCSs were characterized by scanning electron microscopy, nitrogen adsorption-desorption, X-ray photoelectron spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy, and their electrosorption performance in NaCl solution was studied. The results show that NPCSs treated at 1000 °C exhibit an extremely high electrosorption capacity of 14.91 m g g−1 when the initial NaCl concentration is 1000 mg l−1, which shows great improvement compared with their undoped counterpart. The nitrogen doping is suggested to be a very effective method to improve the electrosorption performance, and the NPCSs should be a very promising candidate as electrode material for CDI application.

Porous carbon spheres (PCSs) were fabricated through a fast microwave-assisted approach using sucrose as the precursor in a microwave system and subsequent thermal treatment at 600, 800 and 1000 °C. The morphology, structure and electrochemical performance of the PCSs were characterized by scanning electron microscopy, Raman spectroscopy, nitrogen adsorption-desorption, cyclic voltammetry and electrochemical impedance spectroscopy. Their electrosorption performance in NaCl solution was studied and compared with activated carbon, carbon nanotubes, reduced graphene and carbon aerogels. The results show that due to their high specific surface area and low charge transfer resistance, PCSs treated at 1000 °C exhibit high electrosorption capacity of 5.81 m g g−1 when the initial solution concentration is 500 mg l−1, which is higher than those of other carbon materials.

MoS2-reduced graphene oxide (RGO) composites were synthesized via a facile microwave assisted reduction of graphene oxide in MoS2 precursor solution and subsequent annealing in N2/H2 atmosphere at 800 °C for 2 h. Their morphology, structure and electrochemical performance were characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, N2 adsorption-desorption isotherm, cyclic voltammetry and electrochemical impedance spectroscopy. The MoS2-RGO composites with different RGO loadings were applied as anode materials of sodium ion batteries (SIBs) and they exhibit a maximum reversible specific capacity of about 305 mAh g−1 at a current density of 100 mA g−1 after 50 cycles and excellent rate performance. The results demonstrate that MoS2-RGO could be a potential electrode material for rechargeable SIBs.

A modified membrane capacitive deionization (m-MCDI) device was proposed with high desalination efficiency. The m-MCDI electrodes were fabricated by introducing the anion exchange polymer (dimethyl diallyl ammonium chloride) and cation exchange (polyethyleneimine) polymer into carbon nanotubes (CNTs) electrodes and their desalination performance in NaCl solutions was investigated. The m-MCDI unit cell based on both anion and cation exchange polymers exhibits a high NaCl removal of 93%, much higher than that of conventional capacitive deionization cell with CNTs electrode (25%) or MCDI cell with commercial anion and cation exchange membranes (74%) in a certain experiment at 1.2 V and for an initial conductivity of 50 μS/cm. The large improvement in desalination performance is mainly due to the reduced co-ion expulsion effect by introducing ion exchange polymers and the better contact adhesion between ion exchange polymers and electrodes than between commercial ion exchange membranes and electrodes.

a b s t r a c t CdS–TiO2–Au composites were synthesized via microwave-assisted reaction of CdS precursor and chloroaurate solution with TiO2 suspension using a microwave system. The photocatalytic performance of CdS–TiO2–Au composites in degradation of methyl orange was investigated. The results show that CdS–TiO2–Au composites exhibit an enhanced photocatalytic performance with maximum degradation rate of 98% under visible light irradiation as compared with pure TiO2 (43%) and CdS–TiO2 (80%) composite due to the increased light absorption intensity and the reduction of electron–hole pair recombination with the introduction of Au.

Carbon nanotubes (CNTs)–polyacrylic acid (PAA) composite film has been successfully fabricated by electrophoretic deposition method in PAA aqueous solution containing CNTs and used as electrodes for capacitive deionization (CDI). The PAA serves as the cation-exchange polymer and the matrix to incorporate the CNTs. The CDI unit cell based on CNTs–PAA composite film electrode exhibits a high NaCl removal of 83%, 51% higher than that of the cell based on pure CNTs electrode, with a good regeneration ability.

Carbon nanotubes (CNTs) films have been successfully fabricated by electrophoretic deposition (EPD) technique and used as counter electrodes of dye-sensitized solar cells (DSSCs). The CNTs counter electrodes consisting of a large number of bamboo-like structures with defect-rich edge planes exhibit a highly interconnected network structure with high electrical conductivity and good catalytic activity. A high photovoltaic conversion efficiency of 7.03% is achieved for DSSCs based on the CNTs counter electrodes, which is comparable to the cell based on conventional Pt counter electrode at one sun (AM 1.5G, 100 mW cm −2 ). The results suggest that the present synthetic strategy provides a potential feasibility for the fabrication of low-cost flexible counter electrodes of DSSCs using a facile deposition technique from an environmentally “friendly” solution at low temperature.

The composite films of activated carbon fibers (ACFs) and carbon nanofibers (CNFs) are prepared via chemical vapor deposition of CNFs onto ACFs in different times from 0.5 to 2 h and their electrosorption behaviors in NaCl solution are investigated. The morphology, structure, porous and electrochemical properties are characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, N2 adsorption at 77 K, contact angle goniometer and electrochemical workstation, respectively. The results show that CNFs have been hierarchically grown on the surface of ACFs and the as grown ACF/CNF composite films have less defects, higher specific capacitances, more suitable mesoporous structure and more hydrophilic surface than the pristine ACFs, which is beneficial to their electrosorption performance. The ACFs/CNFs with CNFs deposited in 1 h exhibit an optimized NaCl removal ratio of 80%, 55% higher than that of ACFs and the NaCl electrosorption follows a Langmuir isotherm with a maximum electrosorption capacity of 17.19 mg/g.

Graphene, graphene–ZnO and graphene–SnO 2 films were successfully synthesized and used as electrode materials for electrochemical supercapacitors, respectively. The screen-printing approach was employed to fabricate graphene film on graphite substrate while the ZnO and SnO 2 were deposited on graphene films by ultrasonic spray pyrolysis. The electrochemical performances of these electrodes were comparatively analyzed through electrochemical impedance spectrometry, cyclic voltammetry and chronopotentiometry tests. The results showed that the incorporation of ZnO or SnO 2 improved the capacitive performance of graphene electrode. Graphene–ZnO composite electrode exhibited higher capacitance value (61.7 F/g) and maximum power density (4.8 kW/kg) as compared with graphene–SnO 2 and pure graphene electrodes.