The Disease-- Benzotriazole-based Polymer Synthesis And Photovoltaic Performance

In this dissertation, we focus on the design and synthesis of three series of new benzotriazole based conjugated polymers and photovoltaic applications. Bulk heterojunction polymer solar cells were fabricated using these conjugated polymers blended with PCBM as active layers. Furthermore photovoltaic performance and morphology were also discussed. The main results are as follows:Two new alternating copolymers based on dithienyl benzotriazole segment and phenyl vinyl unit were synthesized by Heck cross coupling method. The organic compounds and polymers were characterized by 1H NMR. The optical and electrochemical properties were investigated using UV-Vis absorption and cyclic voltammetry. They exhibited good optical absorption (from 300 nm to 752 nm for MOPPVDTBTz (P1), and from 300 nm to 654 nm for PPVDTBTz (P2)) with optical bandgap ranging between 1.6-1.9 eV. Preliminary devices showed they had moderate photovoltaic properties delivering a power conversion efficiency of 0.36% and 0.4%, respectively, under the illumination of AM 1.5,100 mW/cm2.Two new alternating copolymers from benzodithiophene and benzotriazole units, namely (PBDTDTBTz) and (PBDTBTz), were designed and synthesized by a typical Stille coupling polymerization method. They were characterized in detail. Photovoltaic devices demonstrated a power conversion efficiency of up to 1.7% and 1.4%, respectively for PBDTDTBTz and PBDTBTz, under the illumination of AM 1.5,100 mW/cm2 with a device structure of ITO/PEDOT: PSS/polymer:PC71BM(1:4)/Ca/Al.The results indicate that the BTz-based copolymers are promising for the application in PSCs.A new dithienyl benzotriazole based conjugated polymer was synthesized by a Suzuki coupling reaction. The polymer was found to be soluble in common organic solvents, such as chloroform, tetrahydrofuran, and chlorobenzene with excellent film forming properties. The polymer film exhibited an absorption band in the wavelength ranging from 300 nm to 610 nm. Preliminary photovoltaic cells based on the composite structure of ITO/PEDOT: PSS/PCDTBTz:PC60BM (1:2 w/w)/Al showed an open-circuit voltage of 0.92 V, a power conversion efficiency of 2.2% and a short circuit current of 5.33 mA·cm-2...