Vertical Stratification Engineering for Organic Bulk-Heterojunction Devices
Vertical Stratification Engineering for Organic Bulk-Heterojunction Devices
复制标题
有机体异质结器件的垂直分层工程
DOI：
10.1021/acsnano.8b00439
复制
发表时间：
2018-05-01
期刊：
影响因子：
17.1
通讯作者：
Chen, Yiwang
中科院分区：
文献类型：
--
作者：
Huang, Liqiang;Wang, Gang;Chen, Yiwang
高效有机太阳能电池（OSC）可以通过组件分子设计的优化，加上界面工程和活性层形貌的控制来生产。然而，体异质结（BHJ）的垂直分层（干燥过程中发生的一种自发活动）仍然是一个尚未解决的复杂问题。应探索调节垂直分离剖面和评估对最终装置的影响的途径，以进一步提高 OSC 的性能。在这里，我们建立了材料表面能、吸收和垂直分层之间的联系，然后可以将其与光伏转换特性联系起来。通过评估通过顺序铸造各个组件以形成多层结构而创建的临时人工垂直分层层的性能，可以实现最佳的垂直分层。调整基底之间的表面能偏移会导致该分层的供体和受体稳定。此外，观察到可见光区域产生的光电流与紧邻电极的供体或受体的量之间的权衡。使用自组装小分子（SASM）实现了基底表面能的改变，这反过来又直接影响界面处聚合物供体与受体的比率。在倒置有机太阳能电池结构中使用三种不同的供体聚合物与两种替代受体结合，ITO（氧化铟锡）/BHJ界面处的聚合物供体分子的浓度相对于受体可以增加。适当选择SASM有助于同步提高外量子效率和功率转换效率超过10.5%。
High-efficiency organic solar cells (OSCs) can be produced through optimization of component molecular design, coupled with interfacial engineering and control of active layer morphology. However, vertical stratification of the bulk-heterojunction (BHJ), a spontaneous activity that occurs during the drying process, remains an intricate problem yet to be solved. Routes toward regulating the vertical separation profile and evaluating the effects on the final device should be explored to further enhance the performance of OSCs. Herein, we establish a connection between the material surface energy, absorption, and vertical stratification, which can then be linked to photovoltaic conversion characteristics. Through assessing the performance of temporary, artificial vertically stratified layers created by the sequential casting of the individual components to form a multilayered structure, optimal vertical stratification can be achieved. Adjusting the surface energy offset between the substrate results in donor and acceptor stabilization of that stratified layer. Further, a trade-off between the photocurrent generated in the visible region and the amount of donor or acceptor in close proximity to the electrode was observed. Modification of the substrate surface energy was achieved using self-assembled small molecules (SASM), which, in turn, directly impacted the polymer donor to acceptor ratio at the interface. Using three different donor polymers in conjunction with two alternative acceptors in an inverted organic solar cell architecture, the concentration of polymer donor molecules at the ITO (indium tin oxide)/BHJ interface could be increased relative to the acceptor. Appropriate selection of SASM facilitated a synchronized enhancement in external quantum efficiency and power conversion efficiencies over 10.5%.