Synthesis And Performance Of A1-D-A2-D-A1 Type Non-fused-ring Nuclear Organic Solar Cell Acceptor Materials

Organic solar cells(OSCs)have received extensive attention from scientific researchers due to their light weight,simple process,and large-area devices prepared by solution processing.This thesis systematically reviews the research progress of non-fullerene electron acceptor(NFAs)materials.In view of the current high-efficiency NFAs materials are constructed from complex fused ring structures,the synthesis steps are cumbersome,the purification is difficult,the yield is low,and the practicality is difficult and other key scientific problems.In this thesis,using the intermolecular non-covalent bond force,through the construction of a new type of non-fused ring electron acceptor material with simple molecular structure,low cost and easy synthesis,the design and synthesis of thienothiophene units based on alkyl chain modification are designed and synthesized.A1-D-A2-D-A1 type linear small molecule electron acceptor material with electron donating(D)unit,different electron withdrawing(A2)skeleton core,and different terminal acceptor(A)groups.The thermal stability,optical properties and electrochemical properties of these acceptor materials are systematically studied.The influences of the molecular structure of these electron acceptor materials on the photoelectric properties of the materials have been preliminarily studied.The research content and results of this thesis are as follows:(1)With cyanorhodanine and indanone as the terminal groups,4,7-dibromo-5,6-difluoro-2-octyl-2H-benzo[d][1,2,3]triazole is the electronwithdrawing framework core,both new receptor materials of BTZC8 RCN and BTZC8 IDD were designed and synthesized,respectively.The influences of BTZC8 RCN and BTZC8 IDD on light absorption capacity,electrochemical energy level,thermal stability and photovoltaic performance were systematically studied.As results,the power conversion efficiencies(PCEs)of the ternary device based on PBDB-T:BTZC8RCN:N2200 and PBDB-T:BTZC8IDD:N2200 are 6.56% and 7.44%,respectively.(2)Based on the first part of the defects of poor miscibility and easy aggregation of materials,4,7-dibromo-5,6-difluoro-2-(2-hexyldecyl)benzo[C]-[1,2,5]thiadiazole is selected as the central nuclear receptor unit,4,7-dibromo-5,6-bis(octyloxy)-2,1,3-benzothiadiazole with high electron mobility as the acceptor unit,and 3-undecylthieno[3,2-b]thiophene as the donor unit,then two new acceptor materials,BTZC16 RCN and BHTRCN,have been obtained.The influences of BTZC16 RCN and BHTRCN on light absorption capacity,electrochemical energy level,thermal stability and photovoltaicperformance have been systematically studied.The PCEs of the ternary devices based on PBDB-T:BTZC16RCN:N2200 and PBDB-T:BHTRCN:N2200 are 7.86 and 7.20%,respectively.(3)In order to avoid over aggregat,introducing a sterically hindered oxyalkyl chain into the donor unit and choosing a simpler bisfluorobenzene unit for the central core,two novel acceptor materials of DFBTTO8 and DFBTTO16 were designed and synthesized.The light absorption capacity and energy level of DFBTTO8 and DFBTTO16 were systematically studied.The PCE of binary device based on PBDB-T:DFBTTO16 is 1.16%.