Miaoliang Huang

An All-Solid-State Dye-Sensitized Solar Cell-Based Poly(N-alkyl-4-vinyl-pyridine iodide) Electrolyte with Efficiency of 5.64%

Using poly(N-methyl-4-vinyl-pyridine iodide), N-methyl-pyridine iodide and iodine, a solid polymer electrolyte with conductivity of 6.41 mS/cm is prepared. On the basis of a solid polymer electrolyte, a conducting graphite layer, a KI block layer, and a vacuum assembling technique, we achieve an all-solid-state dye-sensitized solar cell with total photoelectric conversion efficiency of 5.64% under AM 1.5 simulated solar light (100 mW/cm2) illumination.

Progress on the electrolytes for dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) have aroused intense interest over the past decade owing to their low cost and simple preparation procedures. Much effort has been devoted to the study of electrolytes that enable light-to-electrical power conversion for DSSC applications. This review focuses on recent progress in the field of liquid, solid-state, and quasi-solid-state electrolytes for DSSCs. It is believed that quasi-solid-state electrolytes, especially those utilizing thermosetting gels, are particularly applicable for fabricating high photoelectric performance and long-term stability of DSSCs in practical applications.

A large-area light-weight dye-sensitized solar cell based on all titanium substrates with an efficiency of 6.69% outdoors.

Light-weight PEDOT-Pt/Ti mesh and Ti/TiO(2) foil electrodes are prepared. Owing to the PEDOT-Pt/Ti photocathodes high transparency, good electrocatalytic activity, and low resistance; the Ti/TiO(2) anodes large specific area and high conductivity, a light-weight backside illuminated large-area (100 cm(2) ) dye-sensitized solar cell achieves an energy conversion efficiency of 6.69% under an outdoors sunlight irradiation of 55 mW cm(-2) .

High performance platinum-free counter electrode of molybdenum sulfide–carbon used in dye-sensitized solar cells

A high porous molybdenum sulfide–carbon (MoS2–C) hybrid film was prepared by using an in situ hydrothermal route. The MoS2–C hybrid film served as a low-cost and high efficient platinum-free counter electrode for a dye-sensitized solar cell (DSSC). The cyclic voltammetry, electrochemical impedance spectroscopy and Tafel curve analysis indicate that the MoS2–C electrode possesses low charge transfer resistance on the electrolyte–electrode interface, high electrocatalytic activity and fast reaction kinetics for the reduction of triiodide to iodide at the counter electrode, which is due to large specific surface area and special structure and compositions of MoS2–C film. A DSSC with the novel MoS2–C counter electrode achieve a high power conversion efficiency of 7.69% under standard light illumination, which exceeds that of the DSSC with a Pt counter electrode (6.74%).

Bifacial dye-sensitized solar cells: A strategy to enhance overall efficiency based on transparent polyaniline electrode

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, low-cost, high efficiency, good durability, and easy fabrication. However, enhancing the efficiency of the DSSC still is an important issue. Here we devise a bifacial DSSC based on a transparent polyaniline (PANI) counter electrode (CE). Owing to the sunlight irradiation simultaneously from the front and the rear sides, more dye molecules are excited and more carriers are generated, which results in the enhancement of short-circuit current density and therefore overall conversion efficiency. The photoelectric properties of PANI can be improved by modifying with 4-aminothiophenol (4-ATP). The bifacial DSSC with 4-ATP/PANI CE achieves a light-to-electric energy conversion efficiency of 8.35%, which is increased by ~24.6% compared to the DSSC irradiated from the front only. This new concept along with promising results provides a new approach for enhancing the photovoltaic performances of solar cells.

A simple and high-effective electrolyte mediated with p-phenylenediamine for supercapacitor

A redox intermedium p-phenylenediamine (PPD) with quick reversible faradaic processes is introduced into KOH electrolyte, referred to as pseudocapacitive effect occurring on the electrode/electrolyte surface. The KOH + PPD electrolyte as potential electrolyte for supercapacitors is investigated by UV-Vis spectroscopy and electrochemical methods. As expected, the supercapacitor with KOH + PPD electrolyte has a much higher electrode specific capacitance (605.225 F g−1) than the one with conventional KOH electrolyte (144.037 F g−1) at the same current density of 1 A g−1. Simultaneously, the supercapacitor with KOH + PPD electrolyte exhibits a much higher energy density (19.862 W h kg−1) than the supercapacitor with conventional KOH electrolyte (4.458 W h kg−1). Furthermore, the supercapacitor with KOH + PPD electrolyte shows superior charge–discharge stability. After 4000 cycles, its capacitive retention ratio is still as high as 94.530%.

Conducting film from graphite oxide nanoplatelets and poly(acrylic acid) by layer-by-layer self-assembly

A [poly(acrylic acid)/graphite oxide]n [(PAA/GO)(n)] film with a conductivity of 60 S.cm(-1) was grown layer-by-layer (LbL) using Langmuir-Blodgett self-assembly techniques. GO nanoplatelets were prepared from natural graphite by oxidizing, ball milling, exfoliating, and modifying with cationic surfactant cetyltrimethylammonium bromide (CTAB). The X-ray diffraction pattern reveals that PAA and GO stack orderly LbL and repeatedly in the (PAA/GO)(n) films, and about three carbon molecular layers are superposed on each GO sheet. Fourier transform infrared spectra offer evidence for the interaction between the carboxylic groups on PAA and the CTAB on the surface of the GO nanoplatelets. Electrochemistry measurements show that the conductivity of the (PAA/GO)(n) film depends on the carbon-carbon interlayer height of the GO sheet, and the (PAA/GO)(n) film has a typical positive temperature coefficient effect above the PAA melting temperature. The atomic force microscopy images reveal that CTAB molecules stack in a well-ordered head-to-head structure on both surfaces of the GO nanoplatelets and the GO nanoplatelets are embeded between PAA layers.

Redox-active alkaline electrolyte for carbon-based supercapacitor with pseudocapacitive performance and excellent cyclability

A simple method has been implemented to prepare a stable and effective redox-active alkaline electrolyte by doping m-phenylenediamine into a conventional KOH electrolyte for a carbon-based supercapacitor. The quick electron transfer and reversible Faradic process in the new electrolyte system results in additional pseudocapacitive contribution for a carbon-based supercapacitor. The specific capacitance of the supercapacitor based on the new electrolyte is 78.01 F g−1, which is an increase of 114.16% over that of a supercapacitor based on a conventional KOH electrolyte (36.43 F g−1). Additionally, the supercapacitor exhibits an excellent cyclical stability.

A high performance Pt-free counter electrode of nickel sulfide/multi-wall carbon nanotube/titanium used in dye-sensitized solar cells

Multi-wall carbon nanotubes (MWCNTs) were deposited on a titanium (Ti) foil substrate by using electrophoresis, then a nano-corallines nickel sulfide (NiS) was deposited on the MWCNTs by using a pulse potentiostatic method. The high performance NiS/MWCNT/Ti hybrid film was firstly used as a Pt-free counter electrode (CE) in dye-sensitized solar cells (DSSCs). The surface of MWCNTs was wrapped with a nano-corallines NiS thin film of ∼45 nm in thickness. Under full sunlight illumination (100 mW cm−2, AM 1.5 G), DSSCs with a NiS/MWCNT/Ti CE achieved an enhanced photovoltaic conversion efficiency of 7.90%, while DSSCs with a Pt/Ti CE obtained the efficiency of 6.36%. The characterization of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) indicated that nano-corallines NiS had high electrocatalytic activity for I3− reduction, MWCNTs had high specific surface area and low resistance, and the synergistic effect of NiS and MWCNTs endowed the superior features of the hybrid film. Therefore, the NiS/MWCNT/Ti CE can be used as a promising alternative CE in low-cost and large-scale DSSCs.

Dual functions of YF3:Eu3+ for improving photovoltaic performance of dye-sensitized solar cells

In order to enhance the photovoltaic performance of dye-sensitized solar cell (DSSC), a novel design is demonstrated by introducing rare-earth compound europium ion doped yttrium fluoride (YF3:Eu3+) in TiO2 film in the DSSC. As a conversion luminescence medium, YF3:Eu3+ transfers ultraviolet light to visible light via down-conversion, and increases incident harvest and photocurrent of DSSC. As a p-type dopant, Eu3+ elevates the Fermi level of TiO2 film and thus heightens photovoltage of the DSSC. The conversion luminescence and p-type doping effect are demonstrated by photoluminescence spectra and Mott-Schottky plots. When the ratio of YF3:Eu3+/TiO2 in the doping layer is optimized as 5 wt.%, the light-to-electric energy conversion efficiency of the DSSC reaches 7.74%, which is increased by 32% compared to that of the DSSC without YF3:Eu3+ doping. Double functions of doped rare-earth compound provide a new route for enhancing the photovoltaic performance of solar cells.