(1. 浙江工業(yè)大學(xué) 機(jī)械制造及自動(dòng)化教育部重點(diǎn)實(shí)驗(yàn)室，杭州 310014；
2. 浙江大學(xué) 硅材料國家重點(diǎn)實(shí)驗(yàn)室，杭州 310027)
摘 要: 采用脈沖激光(重復(fù)率為10 Hz，能量密度為4.2 J/cm2)對(duì)蒸餾水中的Ag靶燒蝕不同時(shí)間后，制備得到Ag納米粒子膠體，并對(duì)其進(jìn)行紫外−可見分光光度計(jì)分析和透射電鏡觀察。結(jié)果表明：燒蝕時(shí)間為5~7.5 min時(shí)，Ag納米粒子粒徑及分布隨燒蝕時(shí)間呈減少趨勢(shì)，燒蝕時(shí)間從7.5變化至15 min時(shí)又隨之增加，而燒蝕時(shí)間從15變化至25 min時(shí)又隨之減少；獲得的納米粒子濃度增高，且溶液中粒子的團(tuán)聚率也增大；燒蝕時(shí)間為7.5 min時(shí)，粒子粒徑達(dá)到最小(D=14.48 nm)，粒徑分布最小(d=25.8 nm)。在實(shí)驗(yàn)基礎(chǔ)上，應(yīng)用納米粒子對(duì)脈沖激光自吸收產(chǎn)生的“爆炸”與“熔化生長”模型解釋了燒蝕時(shí)間對(duì)納米粒子膠體的影響規(guī)律，證實(shí)通過改變燒蝕時(shí)間來控制納米粒子尺寸和形貌、以及防止納米粒子發(fā)生團(tuán)聚的可行性。
關(guān)鍵字: Ag；納米粒子膠體；激光燒蝕；爆炸；熔化生長
pulsed laser ablation in distilled water
ZHANG Yin-zhu, YE Zhi-zheng
（1. The MOE Key Laboratory of Mechanical Manufacturing and Automation，
Zhejiang University of Technology, Hangzhou 310014, China;
2. State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China）
Abstract: Silver nanoparticles colloids were prepared by pulsed laser ablation for different time in distilled water with repetition rate of 10 Hz and laser fluence of 4.2 J/cm2. The nanoparticles colloids were characterized by UV-visible transmission spectrometry and transmission electron microscopy. The results show that the average diameter and its distribution of silver colloidal nanoparticles are decreased with prolongation of ablation time from 5 to 7.5 min, while then increased from 7.5 to 15 min, then decreased from 15 to 25 min. When the concentration of Ag nanoparticles becomes higher, the degree of aggregation in the solution also becomes higher. Furthermore, after ablating for 7.5 min, the average diameter is the smallest (D=14.48 nm), and the diameter distribution is the narrowest (d=25.8 nm). Based on the experimental results, the effects mentioned above in terms of “fragmentation” and “melting induced growth” of nanoparticles is explained by self-absorption of laser pulses. Furthermore, it is also confirmed that both the control of nanoparticles size and shape and the prevention of nanoparticles colloid agglomeration are possible by condition of ablation time.
Key words: Ag; nanoparticle colloids; laser ablation; fragmentation; melting induced growth
