Bias dependence of tunneling-electron-induced molecular fluorescence from porphyrin films on noble-metal substrates

作     者：H. W. Liu Y. Ie R. Nishitani Y. Aso H. Iwasaki 

作者机构：The Institute of Scientific and Industrial Research Osaka University Osaka 567-0047 Japan Department of Mathematics Physics and Computer Aided Science Faculty of Engineering Kyushu Institute of Technology Fukuoka 804-8550 Japan 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2007年第75卷第11期

页      面：115429-115429页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

摘      要：We investigated scanning tunneling microscope (STM)-excited luminescence from porphyrin (PhTPP and H2TPP) thin films on metal substrate (Au and Ag) under ambient conditions. Molecular fluorescence similar to the corresponding photoluminescence was observed from PhTPP/Au and H2TPP∕Ag at both STM bias polarities. We found that at the same experimental condition and parameters, the STM-induced luminescence intensities of maxima peak are similar for PhTPP and H2TPP but weaker by a factor of about 4 than that for H2TBPP which we studied previously, probably due to fluorescence quenching by aggregation. The polarity dependence and the bias voltage dependence of the fluorescence intensity for the PhTPP/Au were similar to that for the respective pristine metal. These facts support our proposal that intense molecular fluorescence from porphyrin film on the noble metals is a result of the enhancement of molecular excitation by substrate surface plasmons.