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Nano-reactions at solid surfaces by an atomic force microscope with a molecular-recognition cantilever

通过具有分子识别悬臂的原子力显微镜在固体表面进行纳米反应

基本信息

批准号：
16310072
负责人：
KOBAYASHI Kenkichiro
金额：
$ 10.11万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16310072/
关键词：
AFM Nano-device Nano-reactions Photocatalysis Molecular-recognition DNA self-assembled membrane 原子間力顕微鏡

项目摘要

1. Using an atomic force microscope, we attempted to control the photochemical reactions in nanometer-scale. The photocatalytic decomposition of the stearic-acid film was selectively accelerated at the TiO_2surface where a positive voltage of 10 V was applied under ultraviolet illumination. The spatial resolution of the photocatalytic decomposition was estimated to be 30 nm or less from patterns of stearic-acid films. The AFM-assisted photocatalysis can be explained in terms of the accumulation of photogenerated holes at the TiO_2 surface by applying an electric field. It was found that the AFM-assisted photocatalysis was applicable to oxidation reactions of organic compounds in nano-meter scale.2. We developed a new technique to transcribe nano-patterns produced by AFM assisted lithography. The photocatalysts films of TiO_2, SnO_2, Nb_2O_5, Ga_2O_3 were prepared at room temperature by a RF sputtering technique. These oxide films are amorphous with flat surfaces. In particular, amorpho … More us TiO_2 films prepared at a higher pressure of 2x10^<-2> Torr exhibited the highest photocatalytic activity in these oxide films. We demonstrated that these amorphous TiO_2 films have the photocatalytic ability comparable to that of crystalline one. The high photocatalytic activity may be ascribed to the formation of nano-crystals of TiO_2. The amorphous TiO_2 films, which are in contact with self-assembled membranes of octyl-trichlorosilane (OTS) deposited on Si wafers, decomposed completely OTS films into CO_2 and H_2O within 5 min. The patterns of TiO_2 films were transcribed in part to OTS-SAMs within 30 s, but the resultant patterns are unclear. The suppression of lateral diffusion of reactive species are required to realize photocatalytic lithography.3. SAMs of dodecanethiol and aminothiophenol are formed on cantilevers coated with Au. Current vs. voltage characteristics were measured between Au substrates and these cantilevers modified with SAMs. Drastic differences in current vs. voltage characteristics were found between dodecanethiol and aminothiophenol SAMs: distinct current flow at a small bias voltage for aminothiophenol SAMs. In complex impedance plots, the aminothiophenol SAMs gave rise to small real part of impedance corresponding ac conductance at a frequency less than 5 Hz. Single strand DNA with 60 bases was immobilized to aminothiophenol SAMs deposited on Au substrate. In AFM topographs, there were a large number of networks of DNA because of its polymerization. The cantilever modified with aminophiophenol SAMs leads to no meaningful maps of ac conductivity with respect to the DNA networks. Major reason is the response time of the ac conductivity is too long to draw the map in area of 100 nm x 100 nm. Less

1.利用原子力显微镜，尝试在纳米尺度上控制光化学反应。在紫外光照射下，在10V的正电压下，硬脂酸薄膜在二氧化钛表面的光催化分解被选择性地加速。根据硬脂酸薄膜的图案，光催化分解的空间分辨率估计为30 nm或更低。AFM辅助的光催化作用可以用电场作用下在二氧化钛表面积累的光生空穴来解释。研究发现，原子力显微镜辅助的光催化技术适用于纳米尺度的有机物氧化反应。我们开发了一种新的技术来转录AFM辅助光刻产生的纳米图形。采用射频溅射技术在室温下制备了TiO2、SnO2、Nb2O5、Ga2O3光催化剂薄膜。这些氧化膜是无定形的，表面平坦。具体地说，非晶…在这些氧化物薄膜中，在2×10~(-2)×10~(-2)Torr气压下制备的US_2O_2薄膜具有最高的光催化活性。结果表明，非晶态二氧化钛薄膜具有与晶态二氧化钛薄膜相当的光催化性能。这种高的光催化活性可以归因于纳米二氧化钛的形成。非晶态二氧化钛薄膜与沉积在硅片上的辛基三氯硅烷(OTS)自组装膜接触，在5min内将OTS膜完全分解为CO_2和H_2O。在S的30分钟内，二氧化钛薄膜被部分转录成OTS-SAM，但生成的模式尚不清楚。实现光催化光刻需要抑制活性物质的横向扩散。十二硫醇和氨基硫酚在镀金的悬臂梁上形成自组装膜。测量了Au衬底和用自组装膜修饰的悬臂梁之间的电流-电压特性。十二硫醇和硫代硫酚自组装膜的电流-电压特性有很大的不同：在较小的偏置电压下，硫代氨基酚自组装膜有明显的电流流动。在复阻抗图中，氨基硫酚自组装膜在小于5 Hz的频率下产生了对应交流电导的小的阻抗实部。将60个碱基的单链DNA固定在Au基片上的氨基硫酚自组装膜上。在AFM图谱中，由于DNA的聚合，形成了大量的DNA网络。用氨基酚自组装膜修饰的悬臂梁没有关于DNA网络的有意义的交流电导图。主要原因是交流电导的响应时间太长，无法绘制100 nm×100 nm的区域图。较少