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报道了Al/α-SnPc/ITO夹心结构的瞬态光电压随入射光强度和波长变化的演变特性和稳态连续光照射下的光电压作用光谱。稳态光电压作用光谱和其对应吸收光谱的变化趋势非常接近;而瞬态光电压的大小、极性和响应时间则共同取决于入射光的强度和波长。其中瞬态光电压的正峰部分(相对于ITO电极)只在较强的光照射下才出现,而且其响应时间也总是慢于同一条件下出现的负电压峰。文中对该现象的内在机制作了初步的探讨。 相似文献
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采用斯塔克光谱技术研究了酞菁锡多晶薄膜中的激子跃迁和电荷转移。观察到一系列分子间电荷转移所形成的双分子激子谱带,显示了斯塔克光谱技术在探测淹没于弗伦克尔激子带下面的微弱电荷转移跃迁方面具有独特的优点和很高的灵敏度。 相似文献
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采用第一性原理研究了SnPc分子在Ag(111)表面的吸附构型和电子结构. Sn-up和Sn-down两种优化的吸附构型与实验测量结果非常吻合,SnPc以Sn-down构型吸附在Ag(111)表面显得更稳定. Sn原子在两种吸附构型之间转换所需要能量与转换方向有关,由Sn-up向Sn-down构型转换时需翻越一个1.68 eV的能垒,反之需要2.17 eV. 扫描隧道显微镜理论模拟图像给出实验观测结果的主要特征,Sn-up分子的中心处为一个亮斑,而Sn-down分子中心为一个空洞. 计算结果验证了实验提出的Sn原子吸附位置的转换机理. 相似文献
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Adsorption behavior and electronic structure of tin-phthalocyanine (SnPc) on Ag(111) sur-face with Sn-up and Sn-down conformations are investigated using first-principles calcula-tions. Two predicted adsorption configurations agree well with the experimentally deter-mined structures. SnPc molecule energetically prefers to adsorb on Ag(111) surface with Sn-down conformation. The energy required to move the central Sn atom through the frame of a phthalocyanine molecule, switching from the Sn-up to Sn-down conformation, is about 1.68 eV. The simulated scanning tunneling microscopy images reproduce the main features of experimental observations. Moreover, the experimentally proposed hole attachment mech-anism is verified based on the calculated density of states of SnPc on Ag(111) with three different adsorption configurations. 相似文献
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Normal incidence X-ray standing wave (NIXSW) spectroscopy has been used to determine the orientation of Sn phthalocyanine (SnPc) molecules in a highly ordered, but incommensurate, monolayer on the Ag(1 1 1) surface. Our sample preparation procedure differs from that used in previous work on this system [C. Stadler, S. Hansen, F. Pollinger, C. Kumpf, E. Umbach, T.-L. Lee, J. Zegenhagen, Phys. Rev. B 74 (2006) 035404] and leads to a different unit cell with basis vector lengths of ∼15.0 Å and 15.3 Å (γ = 98°) which is oriented at an angle of ∼5° to the underlying Ag(1 1 1) lattice. Structural parameters extracted from Sn MNN NIXSW spectra indicate that SnPc, a buckled, ‘shuttlecock’ phthalocyanine, adsorbs in a Sn-down geometry with the Sn atom approximately 2.3 Å above the Ag(1 1 1) surface plane. Despite the incommensurate nature of the overlayer, we find a surprisingly high coherent fraction for standing wave data taken for the reflection and argue that this arises from the small domain size of the superstructure. 相似文献
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