Optical studies on nucleation and nanoparticle growth

用空间分辨、时间分辨和选择激发光谱的方法研究了各种团簇和纳米颗粒的成核和纳米颗粒生长：(1)稀有气体中的碱金属和稀土金属团簇：Na，K，Rb，Sm，Eu和Yb，(2)快离子导体玻璃中的纳米颗粒：(AgI)_x-(AgPO_3)_&lt；1-x&gt；，(AgI)_x-(Ag_2Mo_4)_t；1-x&gt；(3)稀土氧化物固体：Eu_2O_3中的(M：Mo，W)和(3)发光团簇。结果表明：(1)稀有气体中的碱金属和稀土金属团簇。发射光谱清楚地表明了激发态之间的能量转移，以及碱金属蒸汽区的能量集中和辐射俘获。(2)纳米粒子在快离子导体玻璃中。光致发光和激发光谱表明，随着AgI浓度的增加，快离子导体玻璃成核和纳米粒子生长。Eu_2O_3中的发光团簇在真空和氧气气氛中的室温连续紫外光照射下，薄膜、微晶和粉末压坯呈现出红色锐线结构和白色宽线结构之间的可逆光致发光光谱变化。可逆现象被解释为Eu离子(Eu^&lt；3+&gt；→Eu^&lt；2+&gt；)的价数变化和结合氧空位和Eu^&lt；2+&gt；离子的发光团簇的结果。

By using the space-resolved, time-resolved and selective excitation spectroscopic methods, we have studied the nucleation and nanoparticle growth of various kinds of clusters and nanoparticles ;(1) alkali metal and rare-earth metal clusters in noble gas : Na, K, Rb, Sm, Eu and Yb,(2) nanoparticles in superionic conductor glasses : (AgI)_x-(AgPO_3)_<1-x>,(AgI)_x-(Ag_2Mo_4)_<1-x> (M : Mo, W) and(3) luminescent clusters in rare-earth oxide solid : Eu_2O_3.The following results are obtained.(1) alkali metal and rare-earth metal clusters in noble gasThe emission spectra indicating the excitation energy transfer between vapour species, energy pooling and radiation trapping in alkali metal vapour zones are clearly observed.(2) nanoparticles in superionic conductor glassThe photoluminescence and excitation spectra indicate the nucleation and nanoparticle growth the superionic conductor glasses with increasing AgI concentration, and also give important information on the electronic states between the nanoparticles and glass matrix.(3) luminescent clusters in Eu_2O_3Under irradiating a CW UV laser light at room temperature in vacuum and oxygen gas atmosphere, the film, microcrystals and powder compact of Eu_2O_3 exhibit a reversible photoluminescence (PL) spectral change between a red sharp-line structure and a white broad one. The reversible phenomena to be observed are interpreted as the results of both the valence-number change of europium ions (Eu^<3+> → Eu^<2+>) and the luminescent clusters combined oxygen vacancies and Eu^<2+> ions.