兼容量产涂布过程的熔融共混结晶方法制备具有平衡相分离结构的高效有机太阳能电池

Melt blending crystallization regulating balanced nanodomains in efficient and scalable coating processed organic solar cells

有机光伏器件中供体受体分子较差的混溶性和结晶不平衡已严重阻碍了其性能的进一步发展,这在兼容量产涂布的过程中尤为明显.本文提出了一种熔融共混结晶策略,在刮涂工艺中实现了分子尺度上有机太阳能电池异质结薄膜共混度与定向结晶度的提升,显著增加了给受体的接触面积并为激子解离与扩散提供高效通道.同时,供体受体间的平衡结晶同步实现了空穴与电子的有效传输和收集.该策略在多种体系中均实现了与传统方法制备器件相近的转换效率,如PM6/IT-4F器件的效率为13.86%(0.04 cm^(2))和11.48%(1 cm^(2));而PM6:BTP-BO-4F和PM6:Y6器件分别实现17.17%和16.14%的效率,显示其极具潜力的应用前景.

The miscibility between active layer donors(D)and acceptors(A)is a key factor impeding the development of organic photovoltaics(OPVs)toward higher performance and large-area production.In this study,melt blending crystallization(MBC)was used to accomplish molecular-level blending and highly oriented crystallization in bulk heterojunction(BHJ)films realized by a scalable blade coating process,which increased the D/A contact area and provided sufficient exciton diffusion and dissociation.At the same time,the highly organized and balanced crystalline nanodomain structures permitted dissociated carriers to be efficiently transmitted and collected,resulting in significantly enhanced short-circuit current density,fill factor,and efficiency of the device by means of optimum melting temperature and quenching rates.The method can be simply incorporated into current efficient OPV material systems and achieve a device performance comparable to the best values.The blade-coating-processed PM6/IT-4F MBC devices achieved an efficiency of 13.86%in a small-area device and 11.48%in a large-area device.A power conversion efficiency(PCE)of 17.17%was obtained in PM6:BTP-BO-4F devices,and a PCE of 16.14%was acquired in PM6:Y6 devices.