Thermal desorption spectroscopy of alkanethiol self-assembled monolayer on Au(111)
Thermal desorption spectroscopy of alkanethiol self-assembled monolayer on Au(111)
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DOI：
10.1143/jjap.35.5866
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发表时间：
1996-11-01
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影响因子：
--
通讯作者：
Knoll, W
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文献类型：
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作者：
Nishida, N;Hara, M;Knoll, W
利用热解吸光谱（TDS）研究了十八烷硫醇(CH3（CH2)(17)SH：单体）自组装单层（sam）在Au（ll）上的吸附和解吸。在TDS光谱中发现了两个具有不同粘附行为的二硫醇(CH3(CH2)(17)S)(2)（+)：二聚体（+））的脱附峰，而十八硫醇(CH3(CH)（17)SH+：单体（+））的脱附峰发生在较低的温度下。在一、二级反应条件下，对各峰的解吸活化能和指前因子进行了估计。分析结果表明，硫代烷基硫化物（RS-Au）具有较强的化学吸附性，而二烷基二硫化物（RS-SR：二聚体）的吸附性较弱。相对弱吸附二聚体的总量在缓慢的反应步骤中明显增加，而单层厚度在SAM形成后几乎保持不变。这一结果表明二聚体分子是在单层中形成的。这种弱吸附二聚体的形成与Schlenoff等人报道的SAM薄膜中的自交换现象密切相关。点。化学。第117(1995)12528条]。
The adsorption and desorption of octadecanethiol (CH3(CH2)(17)SH: monomer) self-assembled monolayers (SAMs) on Au(lll) have been investigated by thermal desorption spectroscopy (TDS). Two desorption peaks of dioctadecyl disulfide ((CH3(CH2)(17)S)(2)(+): dimer(+)) exhibiting different sticking behaviors have been identified in the TDS spectra, while the desorption of octadecanethiol (CH3(CH)(17)SH+: monomer(+)) occurred at a lower temperature than that of the dimer(+). The desorption activation energy and the pre-exponential factor for each peak were estimated assuming first- and second-order reactions. The analysis results suggest that both alkyl thiolate (RS-Au) with strong chemisorption and dialkyl disulfide (RS-SR: dimer) with relatively weak adsorption co-exist in the alkanethiol SAM on An. The total amount of relatively weakly adsorbed dimers increased appreciably in a slow reaction step, while the monolayer thickness remained almost constant after SAM formation. This result suggests that dimer molecules are formed in the monolayer. This formation of weakly adsorbed dimers is strongly related to the self-exchange phenomena in SAM films reported by Schlenoff et al. [J. Am. Chem. Sec. 117 (1995) 12528].