The advantages of 3D materials as guest components of ternary organic solar

cells (TOSCs) are being realized, showing great potential in improving device

performance. However, the correlation between their distinctive 3D structure

and device performance remains largely unexplored. Herein, a 3D acceptor

named SF-HR is cost-effectively synthesized utilizing a twisted spirofluorene

core. SF-HR shows an edge-on oriented packing but not the disordered

aggregation as other 3D molecules. When introduced into D18:Y6 binary

system, SF-HR can induce more predominant face-on packing and finer

domain size in ternary blend, which facilitates exciton dissociation and

multi-direction charge transport. Besides, SF-HR exhibits complementary

absorption and cascaded energy levels with D18 and Y6, contributing to the

improvement of short-circuit current density (Jsc) and open-circuit voltage

(Voc), respectively. Accordingly, the optimized ternary device achieves higher

Voc of 0.893 V, Jsc of 27.13 mA cm?2, and fill factor (FF) of 77.8%, respectively,

than that of the host binary device, yielding an excellent efficiency of 18.85%.

This success demonstrates that the utilization of a crystalline 3D material as a

guest component represents a promising strategy for achieving

state-of-the-art OSCs, which is conducive to understanding the relationship

between 3D guest structure and device performance from a new perspective.