Improving　charge　extraction　and　suppressing　charge　recombination　are　critically　important　to　minimize　the　loss　of　absorbed　photons　and　improve　the　device　performance　of　polymer　solar　cells　(PSCs).　In　this　work,　highly　efficient　PSCs　are　demonstrated　by　progressively　improving　the　charge　extraction　and　suppressing　the　charge　recombination　through　the　combination　of　side-chain　engineering　of　new　nonfullerene　acceptors　(NFAs),　adopting　ternary　blends,　and　introducing　volatilizable　solid　additives.　The　2D　side　chains　on　BTP-Th　induce　a　certain　steric　hindrance　for　molecular　packing　and　phase　separation,　which　is　mitigated　by　fluorination　of　side　chains　on　BTP-FTh.　Moreover,　by　introducing　two　highly　crystalline　molecules　as　the　second　acceptor　and　volatilizable　solid　additive,　respectively,　into　the　BTP-FTh-based　host　blend,　the　molecular　crystallinity　is　significantly　improved　and　the　blend　morphology　is　finely　optimized.　As　expected,　enhanced　charge　extraction　and　suppressed　charge　recombination　are　progressively　realized,　contributing　to　the　largely　improved　fill　factor　(FF)　of　the　resultant　devices.　Accompanied　by　the　enhanced　open-circuit　voltage　(V-oc)　and　short-circuit　current　density　(J(sc)),　a　record　high　power　conversion　efficiency　(PCE)　of　19.05%　is　realized　finally.