分子团簇表面吸附敏化ZnO纳米线的第一性原理研究

ZnO纳米线作为新型太阳能电池结构的重要组成部件之一, 其导电能力直接影响到太阳能电池的性能. 采用密度泛函理论平面波超软赝势方法, 计算并分析了C₂H₆O(乙醇)、 C₆H₅FS(4-氟苯硫酚)、 C₇HF₇S(4-(三氟甲基L)-2, 3, 5, 6-四氟硫代苯酚) 等小分子吸附的六边形结构\langle0001angle ZNWs (ZnO 纳米线) 的几何结构、 吸附能和电子结构. 首先, 通过几何优化得到了不同基团吸附的ZNWs的稳定结构, 同时吸附能计算结果表明C₇HF₇S吸附的体系结构最为稳定, 且吸附呈现放热反应; 其次, 为研究表面敏化对导电性能的影响, 计算了不同小分子基团吸附下的能带结构和态密度, 并利用能带理论分析了表面吸附敏化对禁带宽度的调控机理, 结果分析表明小分子表面吸附敏化对ZNWs的电学性能有一定的影响, 其中C₇H₇FS和C₆H₅FS分子均发生了不同程度的电荷转移.

First-principles study on the sensitization of small molecule adsorbed on ZnO nanowire

The electronic properties of the ZNWs (ZnO nanowire) as one of important part of novel SC (solar cells) are very important, which can greatly affect the performance of the SC. Based on the density function theory combined with the plane-wave ultra soft pseudo-potential method, the structures, the adsorption energies and the electronic structures of the C₂H₆O (ethanol), C₆H₅FS (4-fluoro-benzenethiol), C₇HF₇FS (2, 3, 5, 6- tetrafluoro-4-(trifluoromethyl) benzenethiol) clusters adsorbed (0001) hexangular ZNWs are calculated. Firstly, the most stable configuration is found out from different adsorbed ones based on the principle of lowest energy by calculating their total energy. The results also indicate that C₇HF₇FS adsorption is energetically favorable. Then, the densities of state and the electronic structures of different adsorbed systems are calculated. Furthermore, the mechanism for adjusting the band-gap of the absorbed system is investigated and the results indicate that the chemical modification of ZNWs with the small molecule groups results in little change in the electronic property of the system. Meanwhile, charge transfer takes place to a certain extent between the C₇H₇FS and C₆H₅FS.