Development and Structure/Property Relationship of New Electron Accepting Polymers Based on Thieno[2 ',3 ':4,5]pyrido[2,3-g]thieno[3,2-c]quinoline-4,10-dione for All-Polymer Solar Cells

Abstract

Several electron accepting polymers having weak accepting strong accepting (WA-SA) and strong accepting strong accepting (SA-SA) monomer alternation were synthesized for studies of structure/property relationship in all-polymer solar cells. Two kinds of cyclic amide monomers, 4,10-bis (2-butyloctyl)-thieno [2',3':5,6]pyrido #3,4-g#thieno-#3,2-c#isoquinoline-5,11-dione #TPTI# and 5,11-bis-#2-butyloctyl#-thieno #2',3':4,5# pyrido #2,3-g# thieno #3,2-c# quinoline-4,10-dione #TPTQ#, were synthesized as weak accepting monomers #WA## Difluorinated TPTQ #FTPTQ# and well-known perylene diimide #PDI# monomers were synthesized as strong electron accepting monomers #SA## By using 1-chloronaphthalene #CN# as a cosolvent, the morphology of the polymer blended films can be finely tuned to achieve better ordering toward face-on mode and favorable phase separation between electron donor and acceptor, resulting in significant enhancement of short circuit current #J#sc## and fill factor #FF## The fluorination in the TPTQ unit reduced the dipole moment of the D-A complex and gave a negative effect on a polymer system# PFP showed worse electron accepting property with lower electron mobility than PQP# It is reasoned that the internal polarization plays an important role in the design of electron accepting polymers# As a result, PQP having TPTQ monomer exhibited the best photovoltaic performance with power conversion efficiency #PCE# of 3#52% #V-oc = 0#71 V, J#sc#, = 8#57 mA/cm#2#, FF = 0#58# at a weight ratio of PTB7-Th:PQP = 1:1, under AM 1.5G.