具有溶致变色效应的钛氧簇作为高效有机太阳能电池的阴极界面层OA

Three isostructural Ti6-oxo clusters with the formular of Ti6O4(PhPO3)2(L)2(OiPr)10,where L is 2-dimethylamine benzoate for Ti6-1,3-dimethylamine benzoate for Ti6-2,and 4-dimethylamine benzoate for Ti6-3,were successfully synthesized and characterized.Thereinto,Ti6-3 displayed novel solvent dependent light absorption property.When dissolved in trifluoroethanol related solvent,evident visible light absorption was observed for Ti6-3,which was quite different from its absorption limited within the ultraviolate region in isopropanol related solvent.However,Ti6-1 and Ti6-2 displayed consistent absorption behavior in both of these solvents,respectively.It is worth noting that the solvent dependent absorption property remains quite rare for Ti-oxo cluster materials to date,although this has been commonly observed for organic conjugated materials.Nuclear magnetic resonance measurements revealed that the surface isopropoxide ligands on Ti6-3 were replaced by analogus trifluoroethoxide ligands on the cluster surface,resulting in Ti6-3-F.The solvatochromic effect was further illustrated by density functional theory calculation revealing the tuned energy levels between Ti6-3 and Ti6-3-F.Finally,Ti6-3-F was demonstrated able to serve as excellent cathode interlayer(CIL)in PM6:BO-4Cl and PM6:L8-BO based organic solar cells(OSCs),which achieved high efficiencies of 17.89% and 18.09%,respectively,suggesting its excellence as new CIL materials for high performance OSCs.