Abstract: Herein, two asymmetric hexacyclic fused small molecule acceptors (SMAs), namely BP4F-HU and BP4F-UU, were synthesized. The elongated outside chains in the BP4F-UU molecule played a crucial role in optimizing the morphology of blend film, thereby improving charge mobility and reducing energy loss within the corresponding film. Notably, the PM6:BP4F-UU device exhibited a higher open-circuit voltage (V_oc) of 0.878 V compared to the PM6:BP4F-HU device with a V_oc of 0.863 V. Further, a new wide bandgap SMA named BTP-TA was designed and synthesized as the third component to the PM6:BP4F-UU host binary devices, which showed an ideal complementary absorption spectrum in PM6:BP4F-UU system. In addition, BTP-TA can achieve efficient intermolecular energy transfer to BP4F-UU by fluorescence resonance energy transfer (FRET) pathway, due to the good overlap between the photoluminescence (PL) spectrum of BTP-TA and the absorption region of BP4F-UU. Consequently, ternary devices with 15wt% BTP-TA exhibits broader photon utilization, optimal blend morphology, and reduced charge recombination compared to the corresponding binary devices. Consequently, PM6:BP4F-UU:BTP-TA ternary device achieved an optimal power conversion efficiency (PCE) of 17.83% with simultaneously increased V_oc of 0.905 V, short-circuit current density (J_sc) of 26.14 mA/cm², and fill factor (FF) of 75.38%.