Wilken Sebastian, Wilkens Verena, Scheunemann Dorothea, Nowak Regina-Elisabeth, von Maydell Karsten, Parisi Jürgen, Borchert Holger
Energy and Semiconductor Research Laboratory, Department of Physics, Carl von Ossietzky University of Oldenburg , Carl-von-Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany.
ACS Appl Mater Interfaces. 2015 Jan 14;7(1):287-300. doi: 10.1021/am5061917. Epub 2015 Jan 2.
With the use of two transparent electrodes, organic polymer-fullerene solar cells are semitransparent and may be combined to parallel-connected multijunction devices or used for innovative applications like power-generating windows. A challenging issue is the optimization of the electrodes, to combine high transparency with adequate electric properties. In the present work, we study the potential of sputter-deposited aluminum-doped zinc oxide as an alternative to the widely used but relatively expensive indium tin oxide (ITO) as cathode material in semitransparent polymer-fullerene solar cells. Concerning the anode, we utilized an insulator-metal-insulator structure based on ultrathin Au films embedded between two evaporated MoO3 layers, with the outer MoO3 film (capping layer) serving as a light coupling layer. The performance of the ITO-free semitransparent polymer-fullerene solar cells was systematically studied as dependent on the thickness of the capping layer and the active layer as well as the illumination direction. These variations were found to have strong impact on the obtained photocurrent densities. We performed optical simulations of the electric field distribution within the devices using the transfer-matrix method, to analyze the origin of the current density variations in detail and provide deep insight into the device physics. With the conventional absorber materials studied here, optimized ITO-free and semitransparent devices reached 2.0% power conversion efficiency and a maximum optical transmission of 60%, with the device concept being potentially transferable to other absorber materials.
通过使用两个透明电极，有机聚合物 - 富勒烯太阳能电池是半透明的，可以组合成并联连接的多结器件，或用于诸如发电窗户等创新应用。一个具有挑战性的问题是电极的优化，以将高透明度与适当的电学性能相结合。在本工作中，我们研究了溅射沉积的铝掺杂氧化锌作为半透明聚合物 - 富勒烯太阳能电池中阴极材料的潜力，以替代广泛使用但相对昂贵的氧化铟锡（ITO）。关于阳极，我们采用了一种基于嵌入在两个蒸发的MoO3层之间的超薄金膜的绝缘体 - 金属 - 绝缘体结构，外部的MoO3膜（覆盖层）用作光耦合层。系统地研究了无ITO半透明聚合物 - 富勒烯太阳能电池的性能，该性能取决于覆盖层和活性层的厚度以及光照方向。发现这些变化对获得的光电流密度有很大影响。我们使用转移矩阵法对器件内的电场分布进行了光学模拟，以详细分析电流密度变化的起源，并深入了解器件物理。对于这里研究的传统吸收材料，优化后的无ITO半透明器件达到了2.0%的功率转换效率和60%的最大光学透过率，该器件概念有可能转移到其他吸收材料上。
