Yao Jiannian

Investigation of third-order nonlinear optical properties of two azo-nickel chelate compounds

This paper investigates the third-order nonlinear optical properties of two azo-nickel chelate compounds by the optical Kerr gate method at 830nm wavelength with pulse duration of 120 fs. Both of the two compounds exhibited large third-order optical nonlinearity. The second-order hyperpolarizability, γ, of Compound 1 is of 1.0 × 10−31 esu. Due to the charge transfer, the γ of Compound 2 with electron donor and acceptor group is 4.9 × 10−31 esu, which is a four-time enhancement in comparison with Compound 1. The absorption spectra show that the electron push–pull effect, which induces intramolecular charge transfer, leads to the increased optical nonlinearity.

Unraveling weak interactions in aniline-pyrrole dimer clusters

Weak intermolecular interactions in aniline-pyrrole dimer clusters have been studied by the dispersion-corrected density functional theory (DFT) calculations. Two distinct types of hydrogen bonds are demonstrated with optimized geometric structures and largest interaction energy moduli. Comprehensive spectroscopic analysis is also addressed revealing the orientation-dependent interactions by noting the altered red-shifts of the infrared and Raman activities. Then we employ natural bond orbital (NBO) analysis and atom in molecules (AIM) theory to have determined the origin and relative energetic contributions of the weak interactions in these systems. NBO and AIM calculations confirm the V-shaped dimer cluster is dominated by N−H···N and C−H···π hydrogen bonds, while the J-aggregated isomer is stabilized by N−H···π, n→π* and weak π···π* stacking interactions. The noncovalent interactions are also demonstrated via energy decomposition analysis associated with electrostatic and dispersion contributions.

Optical properties of one-dimensional nanomaterials based on small organic molecules

One-dimensional (1D) nanomaterials synthesized from opto-functional low-molecular-weight organic compounds have drawn great interests for their unique optical properties and potential applications in high speed miniaturized photonic integrations. Compared with their inorganic counterparts, organic nanostructures offer advantages such as their high reactivity, ease of chemical doping and convenience in processing at low temperature. In this article, we begin with a general overview of recent progress in this research area. After that, the construction strategies for achieving 1D nanostructures from small organic functional molecules are introduced. Then we focus on the unique optical properties induced by molecular aggregation in the nanostructures, such as optical waveguide, stimulated emission and electroluminescence. This article concludes with a summary and our perspective about future development in 1D organic molecular nanomaterials and organic integrated photonic devices.

Research progress on organic micro/nanoscale lasers

Micro/nanoscale lasers that can deliver intense coherent light signals at (sub)wavelength scale have attracted great interest because of their promising applications ranging from on-chip information processing to high-throughput sensing. Compared with traditional inorganic materials, organic materials are ideal platforms to construct high performance microlasers, mainly because of their superiority in flexibly assembled structures for high-quality microcavities and abundant excited-state processes with large active cross sections for high gain emissions. This review begins with an overview of the research evolution of organic microlasers in terms of microcavity resonators and energy-level gain. Then a series of strategies to tailor the microcavity structures and excited-state dynamics of organic materials for the modulation of lasing performances are highlighted. Subsequently, we present the design and construction of organic-microlaser-based hybrid structures with advanced photonic functionalities. In the following part, we introduce their applications in chemical sensing, biosensing and integrated nanophotonics. Finally, we provide our outlook on the current challenges as well as the future direction of organic microlasers. It is anticipated that this review will provide inspiration for the development of miniaturized lasers with desired performances by tailoring of excited-state processes and microcavity structures toward practical applications.