Synthesis And Characterization Of Donor And Acceptor Materials For Polymer Solar Cells Devices

Organic polymer solar cells with low cost, light weight simple fabrication process (which can be used in variety of substrate technologies such as low-cost spin coating, inkjet printing, screen printing film preparation), can be fabricated as flexible devices. A range of polymer materials can be designed and used for polymer solar cells, and the polymers also can be modified by designing of materials to improve the performance of the solar cell.In this thesis, major work is focusing on the design and synthesis of new polymer donor materials and fullerene acceptor materials for the application in polymer solar cells.In the polymer donor materials aspect:1. Two new donor-acceptor (D-A) alternative copolymers of benzodithiohene (BDT) donor unit and naphtho[2,3-c]thiophene-4,9-dione (NTDO) acceptor unit with different alkyl side chains, PBDTNTDO-1and PBDTNTDO-2, were synthesized for the application as donor materials in polymer solar cells (PSCs). The new copolymers show good solubility in common organic solvents and broad visible absorption from350nm to670nm. HOMO energy levels of the copolymers were measured by electrochemical cyclic voltammetry and it is-5.14eV for PBDTNTDO-1and-5.19eV for PBDTNTDO-2. The PSCs based on PBDTNTDO-2as donor and PC70BM as acceptor demonstrated power conversion efficiency of1.52%with an open circuit voltage of0.88V and a short circuit current of5.67mA/cm2, under the illumination of AM1.5,100mW/cm2.2. Synthesis of head-to-tail regioregular poly(3-pentyl-thiophene). P3PT shows the similar absorbance and HOMO energy level with P3HT. The PSCs based on P3PT as donor and PC6oBM(or IC60BA, IC70BA)(1:1w/w) as acceptor demonstrated power conversion efficiency of1.66%,3.65%and4.52%under the illumination of AM1.5,100mW/cm2.3. A series of ThCBM-like C6o derivatives with different alkyl were designed and synthesized. ThCBM-1-ThCBM-5show the similar absorbance and LUMO energy level. The PSCs based on P3HT/ThCBM-5(2.87%) show the similar power conversion efficiency with P3HT/ThCBM-3based (2.86%). The P3HT/ThCBM-1based show poor power conversion efficiency of1.49%.