| Photonic crystals and metal nanoparticles are both typical optical functionalmaterials in Optics, which have great application prospect. Photonic crystal is thematerial whose refractive index varies periodically. This periodicity brings photoniccrystals unique dispersion relation. Besides, with suitable parameters, photonic crystalmay own a photon stop band, whose function is similar to electronic stop band in thesemiconductor. Photon stop bands can prevent the light propagation of certainwavelength. As for metal nanoparticles, their surface plasmon can couple with light,change absorption, enhance local electric field and so on, which make them appliedwidely in Optics. Besides, both of photonic crystals and metal nanoparticles can affectthe photoluminescence. In this thesis, I will discuss the research onphotoluminescence of complex system based on these two novel materials andsuitable organic conjugated materials.Alq3is a typical conjugated material which is used widely in OLEDs. Isynthesized PMMA opal photonic crystals enclosing conjugated molecules (Alq3)combining several techniques and then studied photoluminescence using this system.With SEM, I obtained information of samples’ structure. With steady transmittanceand emission spectra, I studied the structure of photon stop bands and the modulationof photonic crystals on photoluminescence simply. With angle dependenttransmittance and emission spectra, I obtained the angle dependence of modulation. Itis concluded in my research that both first-order and high-order photon stop bands caninfluence photoluminescence but with different extent in different direction. After that,I investigated on the fluorescence dynamics of Alq3in photonic crystals with dataobtained using Time-correlated Single Photon Counting (TCSPC). After fitting datawith strentched exponential, I concluded that the decay rate of Alq3could bedecelerated as the PSB of PC approaches the emission peak ofAlq3.Because of its good fluorescence and film-forming property, MEH-PPV isselected to be the matrix of the hybrid films based on metal nanoparticles and polymer. In order to get well-mixed hybrid film, I synthesized Brust’s Gold Nanoparticles andusing them as the metal nanoparticles. With steady absorption and emission spectra, Ifound that the introduction of gold nanoparticles can not only enhance the emissionintensity but also change shape of absorption and emission spectra. These influenceon photoluminescence should be attributed to coupling between plasmon andemission of MEH-PPV. Results from TCSPC showed that the non-radiation delay rateis decelerated in hybrid system. After that, I measured temperature-dependent andexcitation-intensity-dependent emission spectra. It turned out that introduction of goldnanoparticles will decrease excitation energy, increase thermal exchange rate,decrease thermal accumulation and finally increase linearity between emissionintensity and excitation intensity. |
