The Research And Application Of Functional Interlayer In Organic Solar Cell

Organic solar cells(OSCs),which convert sunlight directly to electricity,represent an attractive solar technolog y with outstanding advantages.In order to push the efficiency limits beyond the existing boundaries,one of crucial aspects is a basic understanding of the processes that control and limit the operation of solar cells,another is the interfacial function layer engineering.In this thesis,the interfacial states and the modification of function layer have been investigated by photoelectron spectroscopy(XPS&UPS),vacuum thermal evaporation and spin-coating method etc.In the first part,we focus on the the effects of the tunable electrode work function in open-circuit voltage of two classic type conjugated polymer-fullerene solar cells:Poly(3-hexylthiophene)(P3HT)with[6,6]-phenyl-C61 butyric acid methyl ester(PCBM)and Poly(3-hexylthiophene)(P3HT)with indene-C60 bisadduct(ICBA)blended heterojunctions.Additionally,the novel co-evaporated Al-MoO3 composite film was applied as the buffer layer,which contains highly transparent and possess tunable work functions depended on the Al content,thus allowing us to fine tune the interfacial property at electrode/BHJ interfaces.From experimental data,we found that the open-circuit voltage of organic solar cells was depended on the interfaces states of Al-MoO3 composite film.Our study not only provided the meaningful experimental and interface states analysis,but also gave an insight of relationship between open-circuit voltage(VOc)and the work function(?)of the electrode.In the second part,it is widely recognized that the PEDOT:PSS have been an outstanding material used as anode buffer layer in the polymer solar cells.However,the better devices performance can be achieved by interface modification and doping technique.Here,the chemical states and energy level of the PEDOT:PSS doped with PEI&PEIE were investiagedby x-ray and ultraviolet photoelectron spectroscopy,and the energy level offsets between doped PEDOT:PSS and C60 interfaces were also observed.At the same time,we also investigated the surface morphology of the doped PEDOT:PSS films and the ?-? curves of the cells with the structure of ITO/PEDOT:PSS(modified)/C60/LiF/Al.Finally,the doped PEDOT:PSS as cathode buffer layer was applied in organic solar cells and organic light-emitting diodes.