University of Bayreuth, Macromolecular Chemistry I-Applied Functional Polymers, 95440 Bayreuth, Germany.
ACS Nano. 2009 May 26;3(5):1107-14. doi: 10.1021/nn9001165.
We investigated an innovative concept of general validity based on an organogel/polymer system to generate donor-acceptor nanostructures suitable for charge generation and charge transport. An electron conducting (acceptor) perylene bisimide organogelator forms nanowires in suitable solvents during gelation process. This phenomenon was utilized for its self-assembly in an amorphous hole conducting (donor) polymer matrix to realize an interpenetrating donor-acceptor interface with inherent morphological stability. The self-assembly and interface generation were carried out either stepwise or in a single-step. Morphology of the donor-acceptor network in thin films obtained via both routes were studied by a combination of scanning electron microscopy and atomic force microscopy. Additionally, photoinduced charge separation and charge transport in these systems were tested in organic solar cells. Fabrication steps of multilayer organogel/polymer photovoltaic devices were optimized with respect to morphology and surface roughness by introducing additional smoothening layers and charge injection/blocking layers. An inverted cell geometry was used here in which electrons are collected at the bottom electrode and holes at the top electrode. The simultaneous preparation of the interface exhibits almost 3-fold improvement in device characteristics compared to the successive method. The device characteristics under AM1.5 spectral conditions and 100 mW/cm(2) for the simultaneous preparation route are short circuit current J(sc) = 0.28 mA cm(-2), open circuit voltage V(OC) = 390 mV, fill factor FF = 38%, and a power conversion efficiency eta = 0.041%.
我们研究了一种基于有机凝胶/聚合物体系的通用有效性的创新概念，以生成适合电荷产生和传输的供体-受体纳米结构。一种电子传导（受体）的苝二酰亚胺有机凝胶剂在凝胶化过程中在合适的溶剂中形成纳米线。这种现象被利用来在无定形空穴传导（供体）聚合物基质中进行自组装，以实现具有固有形态稳定性的互穿供体-受体界面。自组装和界面生成可以分步进行，也可以一步完成。通过扫描电子显微镜和原子力显微镜组合研究了通过这两种途径获得的薄膜中供体-受体网络的形态。此外，在有机太阳能电池中测试了这些体系中的光致电荷分离和电荷传输。通过引入额外的平滑层和电荷注入/阻挡层，优化了多层有机凝胶/聚合物光伏器件的制造步骤，以改善形态和表面粗糙度。这里使用了倒置电池结构，其中电子在底部电极收集，空穴在顶部电极收集。与连续方法相比，同时制备界面可使器件特性提高近 3 倍。同时制备路线的 AM1.5 光谱条件和 100 mW/cm(2)下的器件特性为短路电流 J(sc) = 0.28 mA cm(-2)，开路电压 V(OC) = 390 mV，填充因子 FF = 38%，功率转换效率 eta = 0.041%。
