Sexithiophene-Based Photovoltaic Cells with High Light Absorption Coefficient via Crystalline Polymorph Control
Sexithiophene-Based Photovoltaic Cells with High Light Absorption Coefficient via Crystalline Polymorph Control
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DOI：
10.1021/acs.jpcc.7b07953
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发表时间：
2017-09-14
影响因子：
3.7
通讯作者：
Takahashi, Kohshin
中科院分区：
文献类型：
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作者：
Taima, Tetsuya;Shahiduzzaman, Md.;Takahashi, Kohshin
在此，我们报告了一种有效的方法来控制蒸发的α -性噻吩（6T）薄膜的结晶多晶型，方法是在真空下保持它们过夜（12小时）。此外，我们研究了通过真空技术控制6T晶型对有机光伏器件性能的影响，从而使薄膜呈现低温（LT）晶型（其中6T分子的骨架在衬底上平坦，即所谓的“躺下”取向）。我们的研究结果表明，当有机层直接沉积在碘化铜(I)中间层上时，与高温（HT）多晶型相比，低温多晶型中有机骨架与衬底之间的角度减小了。通过将6T薄膜在真空中保持12小时，使6T层的晶型从HT变为LT，太阳能电池的功率转换效率可以从0.58提高到1.77%。
Herein, we report an efficient approach to control the crystalline polymorph of evaporated alpha-sexithiophene (6T) thin films by keeping them overnight (12 h) under vacuum. Further, we investigated the effects on the performance of organic photovoltaic devices of controlling the 6T polymorph via this vacuum technique so that the films take on the low-temperature (LT) polymorph (in which the backbones of the 6T molecules lie flatter on the substrate the so-called "lying-down" orientation). Our results revealed that when the organic layer was deposited directly onto a copper(I) iodide interlayer, the angle between the organic backbone and the substrate was reduced in the LT polymorph compared with the high-temperature (HT) polymorph. The power conversion efficiency of solar cells could thus be enhanced from 0.58 to 1.77% via a change in the crystal polymorph of the 6T layer from HT to LT by simply keeping the films in vacuum for 12 h.