Jin Xiao

Morphology, photophysics and optoelectronics of P3HT nanoparticles and TiO2 nanorods composite

Morphology and photophysics of polymers are critical to the performance of organic optoelectronics. In this work, poly(3-thiophene) (P3HT) nanoparticles were successfully fabricated by the miniemulsion and reprecipitation methods. The P3HT nanoparticles demonstrated uniform distribution with the domain size of ∼40 nm. The photophysics of P3HT nanoparticles was investigated by absorption and steady-state and time-resolved PL spectroscopy. P3HT nanoparticles showed more ordered and longer conjugation length than pristine P3HT. At the same time, P3HT nanoparticles showed aggregate species which are favorable for interchain charge transfer. The organic/inorganic hybrid photodetectors based on P3HT and TiO2 nanorods were fabricated. The superior performance of the photodetector based on P3HT nanoparticle and TiO2 nanorods comes from the efficient charge transfer and large donor/acceptor interface.

New design graded refractive index antireflection coatings for silicon solar cells

Reflectance spectrum of nanoporous silicon dioxide (SiO2) double layer was calculated by using the matrix method. The results were compared with the corresponding spectrum of silicon oxynitride (SiOxNy)–porous silicon (PS) double layer which deposited on nanostructured black silicon coatings. The nanoporous silicon dioxide (SiO2) double layer deposited on nanostructure black silicon antireflection coating presents a lower reflectance in a broad range of solar spectrum. This research outcome may find a wide application in solar cell industry.

Quantum ratchet effect in a time non-uniform double-kicked model

The quantum ratchet effect means that the directed transport emerges in a quantum system without a net force. The delta-kicked model is a quantum Hamiltonian model for the quantum ratchet effect. This paper investigates the quantum ratchet effect based on a time non-uniform double-kicked model, in which two flashing potentials alternately act on a particle with a homogeneous initial state of zero momentum, while the intervals between adjacent actions are not equal. The evolution equation of the state of the particle is derived from its Schrodinger equation, and the numerical method to solve the evolution equation is pointed out. The results show that quantum resonances can induce the ratchet effect in this time non-uniform double-kicked model under certain conditions; some quantum resonances, which cannot induce the ratchet effect in previous models, can induce the ratchet effect in this model, and the strengths of the ratchet effect in this model are stronger than those in previous models under certain conditions. These results enrich people’s understanding of the delta-kicked model, and provides a new optional scheme to control the quantum transport of cold atoms in experiment.

Photoelectrocatalytic degradation of Rhodamine B using graphene and titanium dioxide composite catalyst

Graphene and titanium dioxide (TiO2) composite catalyst has been synthesized by hydrothermal synthesis method, and used for the degradation of Rhodamine B (Rh.B) in water. The photoelectrocatalytic activity of this composite was evaluated by decomposing of Rh.B in water under visible or UV light irradiation. The degradation results indicated that the photoelectrocatalytic performance of this composite catalyst was greatly enhanced due to the improved adsorption performance and separation efficiency of photo-generated carriers possibly. The composite with graphene content of 10 wt.% exhibited superior activity under UV light irradiation. After 30 min of reaction, the photoelectrocatalytic degradation ratio of Rh.B was about 96% when pH = 6–7. The results of this work provide a good method for the treatment of organic wastewater with high performance.

Improve the properties of n-ZnO/p-Si heterojunction by CuSCN buffer layer

Due to the mismatch between ZnO film and p-Si lattice, there are a large number of interface states which seriously affect the photoelectric properties of ZnO/p-Si heterojunction optoelectronic dev...

Anode-supported BaZr0.8Y0.2O3−δ membranes by tape casting and suspension spraying

Dense BaZr0.8Y0.2O3−δ (BZY) proton-conducting electrolyte membranes are successfully fabricated on NiO–BaZr0.1Ce0.7Y0.2O3−δ(NiO–BZCY) using tape casting combined with suspension spraying technique. The NiO–BZCY anode substrates were prepared by the tape-casting method and the BZY electrolyte membranes were prepared on the NiO-BZCY anodes by suspension spraying. The thermal decomposition of the anode green tape prepared by tape casting was investigated by thermogravimetry-differential thermal analysis while the phase structure and the morphology of the anode/electrolyte bi-layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). No obvious reaction was found between NiO and BZCY in anode substrates and gas-tight BZY membranes were achieved after co-sintering at 1450∘C. With Sm0.5Sr0.5CoO3−δ–Ce0.8Sm0.2O2−δ(SSC–SDC) as the composite cathode, a maximum power density of 121 mW cm−2 was obtained at 650∘C for the single cell with 23 μm thick BZY electrolyte. Resistances of the tested cell were investigated under open circuit conditions at different operating temperatures by impedance spectroscopy.

Higher-order nonclassical effects generated by multiple-photon annihilation-then-creation and creation-then-annihilation coherent states*

We explore two observable nonclassical properties of quantum states generated by repeatedly operating annihilation-then-creation (AC) and creation-then-annihilation (CA) on the coherent state, respectively, such as higher-order sub-Poissonian statistics and higher-order squeezing-enhanced effect. The corresponding analytical expressions are derived in detail depending on m. By numerically comparing those quantum properties, it is found that these states above have very different nonclassical properties and nonclassicality is exhibited more strongly after AC operation than after CA operation.

Ratchet Effect in a Triple Delta-Kicked Model

We investigate the quantum ratchet effect in a triple delta-kicked model. Three symmetric flashing potentials alternately act on a particle with a symmetric and homogeneous initial state of zero momentum. Ratchet currents emerge when quantum resonances are excited. Ratchet currents in the triple model may be stronger than those in the previous model. Our work expands upon the quantum delta-kicked model and may contribute to experimental investigation of the quantum transport of cold atoms.

Fabrication and Characterization of p-CuSCN/n-Si Heterojunction Diode

The p-CuSCN /n-Si heterojunction diode have been prepared at a low cost by chemical method. The prepared hexagonal β-CuSCN films are polycrystalline nature. The heterojunction shows a good rectifying behavior and photovoltaic effects. The current and 1/C2 versus voltage curve of the p-CuSCN/ n-Si heterojunction diode was shown. The linear relationships of 1/C2 versus voltage curve imply that the built-in potential Vbi and the conduction band offset of the heterojunction ware found to be 2.1 eV and 1.5 eV, respectively. The current transport mechanism is dominated by the space-charge limited current (SCLC) conduction at forward bias voltages. The electronic potential barrier in p-CuSCN/n-Si heterojunction interface higher than hole at forward bias voltages. In this voltages area, a single carrier injuction was induced and the main current of p-CuSCN/n-Si heterojunction is hole current.This heterojunction diode can be good used for light emission devices and photovoltaic devices.