Synthesis of thermally stable Ag@TiO2 core–shell nanoprisms and plasmon–enhanced optical properties for a P3HT thin film
Synthesis of thermally stable Ag@TiO2 core–shell nanoprisms and plasmon–enhanced optical properties for a P3HT thin film
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DOI：
10.1039/c3ra22918a
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发表时间：
2013-04
期刊：
影响因子：
3.9
通讯作者：
Peng Du;Yinghui Cao;Di Li;Zhenyu Liu;X. Kong;Zaicheng Sun
中科院分区：
文献类型：
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作者：
Peng Du;Yinghui Cao;Di Li;Zhenyu Liu;X. Kong;Zaicheng Sun
我们开发了一种简单的方法，通过溶胶-凝胶法合成Ag@TiO2核壳纳米棱镜（NPs）与一个可调的外壳厚度。通过改变溶胶-凝胶前驱体的用量和反应时间，可以在1 ~ 15 nm范围内精确调节TiO 2壳层的厚度。局域表面等离子体共振（LSPR）的吸收带显示出超过一百纳米的红移与增加的TiO 2壳层厚度。由于引入了TiO 2壳层，Ag纳米颗粒的热稳定性得到了显著提高。我们研究了通过用P3 HT包覆裸Ag和Ag @ TiO 2核壳纳米粒子来增强聚（3-己基噻吩）（P3 HT）的吸收和荧光。类似的吸收增强表明LSPR吸收增强不受超薄TiO 2壳的影响。对于具有裸Ag NP和Ag @ TiO 2核-壳NP的P3 HT杂化膜，分别观察到弱的和显著的荧光增强。裸露的Ag纳米颗粒既作为增强元件又作为复合中心，在一定程度上猝灭了P3 HT的荧光。通过引入超薄TiO 2壳层，有效地抑制了电荷载流子的复合，从而阻止了空穴向银纳米颗粒的转移。
We develop a facile method to synthesize Ag@TiO2 core–shell nanoprisms (NPs) with a tunable shell thickness through a simple sol–gel route. The thickness of the TiO2 shell can be precisely tuned from 1 to 15 nm via changing the reaction time and amount of TiO2 sol–gel precursor. The localized surface plasmon resonance (LSPR) absorption band shows a red-shift of over a hundred nanometers with the increasing TiO2 shell thickness. The thermal stability of the Ag NPs is significantly improved due to the introduction of the TiO2 shell. We investigate the enhanced absorption and fluorescence of poly(3-hexylthiophene) (P3HT) via coating bare Ag and Ag@TiO2 core–shell NPs with P3HT. A similar absorption enhancement indicates that the LSPR absorption enhancement is not affected by the ultra-thin TiO2 shell. Weak and significant fluorescence enhancements are observed for the P3HT hybrid film with bare Ag NPs and Ag@TiO2 core–shell NPs, respectively. The bare Ag NPs work as both an enhancement element and a recombination center, which quench the P3HT fluorescence to some degree. The recombination of the charge carriers is effectively depressed by introducing the ultra-thin TiO2 shell, which blocks the hole transfer to the Ag NPs.