Cha Hyojung
Department of Hydrogen and Renewable Energy, Kyungpook National University, Daegu 41566, Republic of Korea.
Materials (Basel). 2023 Jan 12;16(2):737. doi: 10.3390/ma16020737.
Non-fullerene acceptors have recently attracted tremendous interest due to their potential as alternatives to fullerene derivatives in bulk-heterojunction solar cells. Nevertheless, physical understanding of charge carrier generation and transfer mechanism that occurred at the interface between the non-fullerene molecule and donor polymer is still behind their enhanced photovoltaic performance. Here we report examples of a non-planar perylene dimer (TP) as an electron acceptor and achieve a power conversion efficiency of 6.29% in a fullerene-free solar cell. Photoluminescence (PL) measurements show high quenching efficiency driven by the excitons of both conjugated polymer and TP molecule, respectively, indicating efficient electron and hole transfer, which can support a highly intermixed phase of blends measured by atomic force microscopy (AFM) and grazing incident wide-angle X-ray diffraction (GIWAXS). Femtosecond transient absorption spectroscopy (fs-TAS) reveals that the fast exciton dissociation process from TP molecule to donor polymer contributes to additionally increasing current density, leading to stronger incident photon to current efficiency in the visible region.
非富勒烯受体最近因其在体异质结太阳能电池中作为富勒烯衍生物替代品的潜力而引起了极大的关注。然而，对于非富勒烯分子与供体聚合物界面处发生的电荷载流子产生和转移机制的物理理解仍落后于其增强的光伏性能。在此，我们报道了一种非平面苝二聚体（TP）作为电子受体的实例，并在无富勒烯太阳能电池中实现了6.29%的功率转换效率。光致发光（PL）测量表明，共轭聚合物和TP分子的激子分别驱动了高猝灭效率，这表明有效的电子和空穴转移，这可以支持通过原子力显微镜（AFM）和掠入射广角X射线衍射（GIWAXS）测量的高度混合的共混物相。飞秒瞬态吸收光谱（fs-TAS）表明，从TP分子到供体聚合物的快速激子解离过程有助于额外增加电流密度，从而在可见光区域产生更强的入射光子到电流效率。
