Abstract
Two new non-fullerene (NF) acceptors, namely BDTIT-M and BDTThIT-M, were rationally designed to optimize the energy levels and optical bandgap. BDTIT-M is derived by changing the end-group of NFBDT into slightly weak DCI-M, and BDTThIT-M is obtained by adding two conjugated thiophene side-chains into a ladder-type core of BDTIT-M. By incorporating with the polymer donor PBDB-T, BDTIT-M based organic solar cells (OSCs) deliver a higher PCE of 11.31% compared to that of NFBDT based cells, which is mainly attributed to the increased VOC and FF. A higher PCE of 12.12% with a small energy loss of ∼0.588 eV is achieved compared with BDTThIT-M based OSCs, benefiting from the elevated LUMO level, narrowed bandgap, and enhanced absorption coefficient and electron mobility of BDTThIT-M compared with BDTIT-M. The combination of a methyl-modified end-group and conjugated side-chain should be an efficient strategy to elevate the LUMO and HOMO levels with different amplitudes for realizing simultaneous improvement in VOC and JSC.
| Original language | English |
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| Pages (from-to) | 2468-2475 |
| Number of pages | 8 |
| Journal | Journal of Materials Chemistry A |
| Volume | 6 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2018 |
| Externally published | Yes |