We investigate the effect of hyperfine interaction on magnetoresistance in nonmagenetic organic semiconductors. A Lorentz-type magnetoresistance is obtained from hyperfine interaction-dependent spin precession picture. The magnetoresistance depends on initial spin orientation of electron to hole in electron-hole pairs. Increasing hyperfine interaction slows down change of the magnetoresistance with magnetic field. The field dependence, the sign and saturation value of the magnetoresistances are composite effects of recombination and dissociation rate constants of singlet and triplet electron-hole pairs.

A method for characterizing the morphology property of ZnO film surface with Gaussian correlation is investigated. The parameters of root-mean-square roughness w and lateral correlation lengthξare introduced in Gaussian model to describe the correlation properties of the random film surfaces. In the experimental performance, ZnO thin films are grown on quartz glass and silicon substrates by the reactive radio-frequency magnetron sputtering method under different deposition pressure. The surface morphologies of the film surface are scanned by an atomic force microscopy. The height auto-correlation functions and root-mean-square roughness are obtained by using the numerical calculus method. Carried on the fitting with the Gaussian function to the height auto-correlation function data, the lateral correlation lengths are extracted to describe the statistical properties of ZnO thin film in mathematics with other parameters.

Series of star-shaped molecules based on 1,3,5-triazine core have been synthesized via CF3SO3H-mediated cyclotrimerization reaction, and then characterized by 1H-NMR, 13C-NMR, MALDI-TOF-MS, and elemental analysis. The effects of different factors, such as the steric hindrance and electronegativity on the reaction efficiency, are systematically studied. The results indicate that the steric hindrance plays an important role in the reaction, while electronegativity has little impact on this reaction. In addition, the bridges including ethylene group and carbon atom between 1,3,5-triazine core and peripherals are firstly studied in this work, which expands the application of CF3SO3H-mediated cyclotrimerization reaction. Moreover, we have successfully broadened the cyclotrimerization reaction to the preparation of 1,3,5-triazine derivatives with different substituents as the peripheral, which is promising for preparation of single-layer multi-functional optoelectronic materials.