Studies On The Synthesis And Characterization Of Cross-linkable Bulk -heterojunction Solar Cell Materials

Bulk heterojunction solar cells (BHJSCs) are under intense investigation due to their greatpotential as light weight, flexible and good thermal stabile photovoltaic devices. Currently, BHJSChas reached a power-conversion efficiency up to 7.4% (AM1.5, 100mW/cm2), approaching theexpected value for commercialization. However, in practice, a general drawback of the BHJSC isthat the transport and collection of charges in a disordered nanoscale blend can be hindered byphase boundaries and discontinuities such as spherical objects and cul-de-sacs. Thus, it is hard toguarantee the exciton diffusion length which is limited to about 10 nm. One way to overcome thedrawback is to prepare ordered bulk heterojunction films. This thesis is focused on introducingcross-linkable groups into series polythiophene donor materials and C60 acceptor materials. Then,the photophysical and electrochemical properties of these materials are investigated. Finally, thedonor and acceptor materials are cross-linked together to form a regular-shaped bulk heterojunctionstructurefilmbythermalannealing.Thecontentsofthisthesisareasfollows:1,A series of conjugated polythiophene P(MET-co-3HT)-10%~PMET with cross-linkable groupsas donormaterials were designed andsynthesized.For comparison,the convential P3HT,whichiswidelyusedinpolymersolarcell,hasalsobeensynthesized.Thestructuresofthesepolymersare chareaterized. The thermalphysical, photophysical and electrochemical properties of thesepolymersarestudied.2,C60 acceptor materials modified with a cross-linkable group, which are namedCross-linkable-C60, were also designed and synthesized. The structural characterization of thesematerials was carried out. The photophysical and electrochemical properties ofCross-linkable-C60werestudied.3,The donor P(MET-co-3HT)-50% and acceptor Cross-linkable-C60 materials were crosslinkedtogether to form regular-shaped bulk heterojunction structure film by thermal annealing. Thepropertiesofthefinalmaterialswerestudied.