Understanding the Vertical Composition Gradient in Sequentially Deposited Photoactive Layers for Organic Photovoltaics
발표자
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초록
내용
In organic photovoltaic (OPV) cells, the morphology of the active layer is the most critical factor influencing device performance. Recently a sequential deposition (SD) method has been reported to control the morphology of active layer with a vertical composition gradient. However, understanding the effects of various factors (solvent, temperature, additives, etc.) on the vertical composition gradient in the SD based active layer remains limited. To solve this, we fabricate an OPV cell using the polymer donor, PM6, and the non-fullerene acceptor, BTP-eC9, via the SD method. Our goal is to determine how the aforementioned factors influence the vertical composition of the active layer. The morphology of the photoactive layer is monitored using atomic force microscopy (AFM), while exciton quenching is analyzed through time-resolved photoluminescence (TRPL). Also, nanosecond transient absorption spectroscopy (ns-TAS) is employed to investigate the behavior of the charge carrier dynamics.