论文标题
带有可调节的无定形壳厚度和芯壳结构调制的牙脲纳米晶体通过水性阳离子 - 交换
Telluride nanocrystals with adjustable amorphous shell thickness and core-shell structure modulation by aqueous cation-exchange
论文作者
论文摘要
工程核心壳胶体半导体纳米颗粒（CSNP）的结构具有吸引力，因为有可能增强光诱导的电荷转移（PICT）并引起有利的光学和电子特性。尽管如此，Telluride CSNP对高温的敏感性使精确调节其表面结晶度的挑战。本文中，我们制定了一种使用水性阳离子交换（ACE）合成带有薄无定形壳的合成telluride CSNP的有效策略。通过更改40C范围内的合成温度，CDTE纳米颗粒的结晶度可以控制，从没有可检测到的无定形壳（C-CDTE）的完美晶体到核心壳结构，其结晶CDTE NP核心覆盖着由可调厚度高达7-8nm（C@A-CDTE）的无态厚度的壳壳覆盖的。第二个ACE步骤将C@A-CDTE转换为Crystalline CDTE@HGTE Core-Shell NP。 C@A-CDTE纳米颗粒在60C下合成并具有4-5 nm厚的无定形壳，表现出最高的表面增强拉曼散射活性，高增强因子在8.82x10^5左右，归因于无异形的壳和晶体之间的耦合。
Engineering the structure of core-shell colloidal semiconductor nanoparticles (CSNPs) is attractive due to the potential to enhance photo-induced charge transfer (PICT) and induce favourable optical and electronic properties. Nonetheless, the sensitivity of telluride CSNPs to high temperatures makes it challenging to precisely modulate their surface crystallinity. Herein, we have developed an efficient strategy for synthesising telluride CSNPs with thin amorphous shells using aqueous cation exchange (ACE). By changing the synthesis temperature in the range 40 to 110C, the crystallinity of the CdTe nanoparticles was controllable from perfect crystals with no detectable amorphous shell (c-CdTe) to a core-shell structure with a crystalline CdTe NP core covered by an amorphous shell of tunable thickness up to 7-8nm (c@a-CdTe) . A second ACE step transformed the c@a-CdTe to crystalline CdTe@HgTe core-shell NPs. The c@a-CdTe nanoparticles synthesized at 60C and having a 4-5 nm thick amorphous shell, exhibited the highest surface-enhanced Raman scattering activity with a high enhancement factor around 8.82x10^5, attributed to the coupling between the amorphous shell and the crystalline core.
