Ichiyanagi Kouhei, Sekiguchi Hiroshi, Sato Tokushi, Nozawa Shunsuke, Tomita Ayana, Hoshino Manabu, Adachi Shin-ichi, Sasaki Yuji C
Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.
Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1 Sayo, Hyogo 679-5198, Japan.
J Synchrotron Radiat. 2015 Jan;22(1):29-33. doi: 10.1107/S1600577514019730. Epub 2015 Jan 1.
Picosecond time-resolved X-ray diffraction has been used to study the nanoscale thermal transportation dynamics of bare gold nanocrystals and thiol-based self-assembled monolayer (SAM)-coated integrated gold nanocrystals on a SiO2 glass substrate. A temporal lattice expansion of 0.30-0.33% was observed in the bare and SAM-coated nanocrystals on the glass substrate; the thermal energy inside the gold nanocrystals was transported to the contacted substrate through the gold-SiO2 interface. The interfacial thermal conductivity between the single-layered gold nanocrystal film and the SiO2 substrate is estimated to be 45 MW m(-2) K(-1) from the decay of the Au 111 peak shift, which was linearly dependent on the transient temperature. For the SAM-coated gold nanocrystals, the thermal dissipation was faster than that of the bare gold nanocrystal film. The thermal flow from the nanocrystals to the SAM-coated molecules promotes heat dissipation from the laser-heated SAM-coated gold nanocrystals. The thermal transportation of the laser-heated SAM-coated gold nanocrystal film was analyzed using the bidirectional thermal dissipation model.
皮秒时间分辨X射线衍射已被用于研究裸露的金纳米晶体以及在SiO₂玻璃衬底上基于硫醇的自组装单分子层（SAM）包覆的集成金纳米晶体的纳米级热输运动力学。在玻璃衬底上的裸露和SAM包覆的纳米晶体中观察到了0.30 - 0.33%的时间晶格膨胀；金纳米晶体内的热能通过金 - SiO₂界面传输到接触的衬底。根据Au 111峰位移的衰减估计，单层金纳米晶体薄膜与SiO₂衬底之间的界面热导率为45 MW m⁻² K⁻¹，其与瞬态温度呈线性相关。对于SAM包覆的金纳米晶体，热耗散比裸露的金纳米晶体薄膜更快。从纳米晶体到SAM包覆分子的热流促进了激光加热的SAM包覆金纳米晶体的散热。使用双向热耗散模型分析了激光加热的SAM包覆金纳米晶体薄膜的热输运。
