School of Chemistry Physics and Mechanical Engineering, Queensland University of Technology, George St, 4000 Brisbane, Australia.
Beilstein J Nanotechnol. 2012;3:524-32. doi: 10.3762/bjnano.3.60. Epub 2012 Jul 19.
The electrical performance of indium tin oxide (ITO) coated glass was improved by including a controlled layer of carbon nanotubes directly on top of the ITO film. Multiwall carbon nanotubes (MWCNTs) were synthesized by chemical vapor deposition, using ultrathin Fe layers as catalyst. The process parameters (temperature, gas flow and duration) were carefully refined to obtain the appropriate size and density of MWCNTs with a minimum decrease of the light harvesting in the cell. When used as anodes for organic solar cells based on poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM), the MWCNT-enhanced electrodes are found to improve the charge-carrier extraction from the photoactive blend, thanks to the additional percolation paths provided by the CNTs. The work function of as-modified ITO surfaces was measured by the Kelvin probe method to be 4.95 eV, resulting in an improved matching to the highest occupied molecular orbital level of the P3HT. This is in turn expected to increase the hole transport and collection at the anode, contributing to the significant increase of current density and open-circuit voltage observed in test cells created with such MWCNT-enhanced electrodes.
通过在 ITO 薄膜顶部直接包含一层受控的碳纳米管，改善了氧化铟锡（ITO）涂层玻璃的电气性能。使用超薄膜 Fe 层作为催化剂，通过化学气相沉积合成多壁碳纳米管（MWCNT）。仔细优化了工艺参数（温度，气流和持续时间），以获得具有最小光捕获损失的适当尺寸和密度的 MWCNT。当用作基于聚（3-己基噻吩）（P3HT）和苯基-C61-丁酸甲酯（PCBM）的有机太阳能电池的阳极时，发现增强了 CNT 的电极改善了从光活性混合物中提取载流子的效率，这要归功于 CNT 提供的额外渗流路径。通过 Kelvin 探针法测量了经修饰的 ITO 表面的功函数，结果为 4.95eV，这与 P3HT 的最高占据分子轨道能级更好地匹配。这反过来又有望增加在阳极处的空穴传输和收集，从而有助于观察到使用这种增强了 CNT 的电极制成的测试电池中的电流密度和开路电压的显著增加。
