Kikuchi S, Takahashi Y, Sakata T
Appl Opt. 1969 Jan 1;8 Suppl 1:42-4.
The contact potential difference between an undyed or dyed zinc oxide powder layer and a gold reference electrode is measured by the Kelvin method. The work function (Phi(ZnO)) of polycrystalline zinc oxide covered by an optical sensitizing dye (rose bengal) grows with increasing adsorbed dye concentration on the zinc oxide surface, reached its maximum value at the dye concentration, 5.0 x 10 (-7) mole/g of ZnO, and then decreased with increasing dye concentration. The value of Phi(ZnO) is constant at concentrations larger than 76.5 10 (-7) mole/g of ZnO. In air, the measured value of Phi(ZnO) for undyed polycrystalline zinc oxide is 4.7 eV, and the maximum value of dyed ZnO is 4.82 eV. From these experimental results, it is suggested that the adsorbed dye on the zinc oxide surface makes but small contribution to the work function of zinc oxide; adsorption is due to dipole forces with the negative pole outermost. Some analysis of the numerical values is made on the dipole moment amplitude of the adsorbed dye and the potential barrier height formed by the adsorption and coverage of the dye on the surface of zinc oxide grains. It is shown that the results of these analyses give reasonable values for understanding the experimental data. A model is proposed to explain these experimental results.
采用开尔文方法测量未染色或染色的氧化锌粉末层与金参比电极之间的接触电位差。被光学增感染料（孟加拉玫瑰红）覆盖的多晶氧化锌的功函数（Phi(ZnO)）随着氧化锌表面吸附染料浓度的增加而增大，在染料浓度为5.0×10⁻⁷摩尔/克氧化锌时达到最大值，然后随着染料浓度的增加而降低。当浓度大于76.5×10⁻⁷摩尔/克氧化锌时，Phi(ZnO)的值保持恒定。在空气中，未染色的多晶氧化锌的Phi(ZnO)测量值为4.7电子伏特，染色氧化锌的最大值为4.82电子伏特。从这些实验结果可以看出，氧化锌表面吸附的染料对氧化锌的功函数贡献很小；吸附是由于偶极力，负极在最外层。对吸附染料的偶极矩幅度以及染料在氧化锌颗粒表面的吸附和覆盖所形成的势垒高度进行了一些数值分析。结果表明，这些分析结果为理解实验数据提供了合理的值。提出了一个模型来解释这些实验结果。
