Influence of Defects on the Reactivity of Organic Surfaces
Influence of Defects on the Reactivity of Organic Surfaces
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DOI：
10.1021/acs.jpcc.8b04635
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发表时间：
2018-07-12
影响因子：
3.7
通讯作者：
Ciszek, Jacob W.
中科院分区：
文献类型：
--
作者：
Deye, Gregory J.;Vicente, Juvinch R.;Ciszek, Jacob W.
有机固体中的分子取向限制了适用的表面反应的范围，反应官能团通常是凹陷的，不能被吸附。为了在前述的惰性取向中诱导反应活性，缺陷介导的机制被用来功能化薄膜相并五苯。通过偏振调制红外反射吸收光谱(PM-IRRAS)和原子力显微镜(AFM)测定的反应数据与缺陷密度的关联，证实了这一机理。通过可控地改变戊二烯薄膜中的晶界数量，反应可以从接近于零到覆盖超过一个单分子层。广泛的报道表明，反应从缺陷传播到整个颗粒，这一预测是通过直接观察从单个位错沿表面进行的反应(通过扫描电子显微镜)而得到证实的。结果支持这样一种机制，即反应是在缺陷位置启动的，特别是晶区的边界，这打开了(001)并五苯向进入吸附的不利分子方向。这种结构及其成功的反应特别适用于有机薄膜晶体管(OTFT)器件。
Molecular orientation within organic solids limits the range of applicable surface reactions, with reactive functionalities often recessed and inaccessible to adsorbates. To induce reactivity in heretofore inert orientations of acenes, a defect-mediated mechanism is utilized to functionalize thin-film phase pentacene. This mechanism was demonstrated via correlation of reaction data to defect density, determined via polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) and atomic force microscopy (AFM). By controllably varying the amount of grain boundaries in the acene films, the reaction can be varied from near zero to coverage exceeding a monolayer. The extensive coverage suggests that the reaction propagates from the defects throughout the grains, a prediction borne out via direct observation of reaction progression along the surface from a single dislocation (via scanning electron microscopy). The results support a mechanism whereby the reaction is initialized at the defect sites, especially boundaries of crystal domains, which opens the unfavorable molecular orientation of the (001) pentacene to incoming adsorbates. This configuration and its successful reaction is especially relevant to organic thin-film transistor (OTFT) devices.