Hengchao Sun

Electrophoretic Deposition of a Reduced Graphene–Au Nanoparticle Composite Film as Counter Electrode for CdS Quantum Dot‐Sensitized Solar Cells

A reduced graphene (RG)-Au nanoparticle composite film is successfully fabricated by electrophoretic deposition and used as counter electrode for quantum dot-sensitized solar cells. The RG-Au composite is prepared by one-step microwave-assisted reduction of chloroaurate in alkaline solution with graphite oxide dispersion. Under one sun illumination (AM 1.5 G, 100 mW cm(-2)), the cell with a RG-Au counter electrode shows an energy conversion efficiency of 1.36 %, which is higher than those of cells employing conventional Pt or Au counter electrodes, due to the superior combination of highly catalytic Au nanoparticles and the conductive graphene network structure.

Electrospun nest-shaped TiO2 structures as a scattering layer for dye sensitized solar cells

Nest-shaped TiO2 (NS-TiO2) structures were fabricated by an electrospinning technique and used as an effective scattering layer on the top of TiO2 nano-particle electrodes in dye sensitized solar cells (DSSCs). The NS-TiO2 scattering layer enhanced the photocurrent of DSSCs due to the enhanced light harvesting via the improved light scattering and lower electron transfer resistance. Under one sun illumination (AM 1.5G, 100 mW cm−2), a high efficiency of 8.02% was achieved for the cell with a NS-TiO2 scattering layer, which was an increase of 7.1% compared to the cell without a scattering layer (7.49%).

Long afterglow SrAl2O4:Eu,Dy phosphors for CdS quantum dot-sensitized solar cells with enhanced photovoltaic performance

An efficient bifunctional structured layer composed of long afterglow SrAl2O4:Eu,Dy phosphors on top of a transparent layer of nanocrystalline TiO2 was fabricated for use in CdS quantum dot-sensitized solar cells (QDSSCs). The introduction of SrAl2O4:Eu,Dy increases the photocurrent of the QDSSCs mainly due to enhanced light harvesting abilities via improved light absorption and scattering. Under one sun illumination (AM 1.5G, 100 mW cm−2), cells containing SrAl2O4:Eu,Dy show a marked improvement in their conversion efficiency (1.24%) compared with cells without SrAl2O4:Eu,Dy (0.98%). After one sun illumination for 1 min, after which the light source was turned off, cells containing SrAl2O4:Eu,Dy show an efficiency of 0.07% under dark conditions due to the irradiation by the long persistent light from SrAl2O4:Eu,Dy. The present strategy should provide a possibility to fulfil the operation of solar cells even in the dark.

Microwave synthesis of high luminescent aqueous CdSe/CdS/ZnS quantum dots for crystalline silicon solar cells with enhanced photovoltaic performance

Water-dispersed CdSe/CdS/ZnS core/shell/shell quantum dots (QDs) with the highest quantum yield of 25.4% were first synthesized for each component by microwave irradiation. As-prepared QDs do not only possess a large Stokes shift but also exhibit excellent repeatability. They can convert near UV and blue light with lower sensitivity to the Si solar cell to red light at which the solar cell has higher sensitivity. The fabricated CdSe/CdS/ZnS QDs/SiO2 composite films were applied to Si solar cells as luminescent down-shifting layers and the effect of QDs on the photoelectric conversion efficiency of photovoltaic modules was investigated. Under one sun illumination, the composite film containing an appropriate amount of CdSe/CdS/ZnS QDs effectively enhances the photoelectric conversion efficiency of the Si solar cell by spectral down-shifting as compared to the bare glass substrate, and the maximum achieves 16.14%.

Enhanced performance of cadmium selenide quantum dot-sensitized solar cells by incorporating long afterglow europium, dysprosium co-doped strontium aluminate phosphors.

CdSe quantum dot-sensitized solar cells based on an efficient bifunctional structured layer composed of long afterglow SrAl2O4:Eu,Dy phosphors on top of a transparent layer of nanocrystalline TiO2 were fabricated and their photovoltaic performances were investigated. The results show that a high power conversion efficiency of 1.22% is achieved for the cell with SrAl2O4:Eu,Dy at one sun illumination (AM 1.5 G, 100 mW cm(-2)), which is an increase of 48% compared to the cell without SrAl2O4:Eu,Dy (0.82%). After one sun illumination for 1 min and subsequent turn off of the light source, the cell with SrAl2O4:Eu,Dy still shows an efficiency of 0.04% under dark condition due to the irradiation by the long persistent light from SrAl2O4:Eu,Dy. The present strategy should provide a possibility to fulfill the operation of solar cells even in the dark.

Nitrogen-doped carbon microspheres counter electrodes for dye-sensitized solar cells by microwave assisted method

Nitrogen-doped carbon microspheres (NCSs) were fabricated via a microwave-assisted method followed by thermal treatment in an ammonia atmosphere and used as counter electrodes for dye-sensitized solar cells. The results show that the cell with NCSs treated at 900 °C exhibits a maximum conversion efficiency of 6.28% at one sun (AM 1.5G, 100 mW cm−2), which is comparable to the one for the cell with conventional Pt counter electrode.

Carbon microspheres via microwave-assisted synthesis as counter electrodes of dye-sensitized solar cells.

Carbon microspheres (CSs) were successfully fabricated and used as counter electrodes of dye-sensitized solar cells (DSSCs). CSs were obtained 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. A maximum photovoltaic conversion efficiency of 5.5% is achieved for DSSCs based on the CSs counter electrodes, which is comparable to the cell based on conventional Pt counter electrode at one sun (AM 1.5 G, 100 mW cm(-2)). The results suggest the CSs to be a potential candidate for counter electrodes of DSSCs.