Quaternary Solar Cells with 12.5% Efficiency Enabled with Non‐Fullerene and Fullerene Acceptor Guests to Improve Open Circuit Voltage and Film Morphology. Issue 21 (18th September 2019)

• Record Type: Journal Article
• Authors: Li, Weiping; Liu, Wenxu; Zhang, Xin; Yan, Dong; Liu, Feng; Zhan, Chuanlang
• Is Part Of: Macromolecular rapid communications. Volume 40:Issue 21(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-09-18
• Subjects: fullerenes -- non‐fullerene -- quaternary solar cells -- small molecule acceptors; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.201900353
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract: Designing the bulk‐heterojunction structure (binary, ternary and quaternary) is of great fundamental interest for relaxing the trade‐off between open circuit voltage ( V oc ) and short circuit current density ( J sc ). Herein, a new quaternary blended material system is reported with a nonfullerene and PC71 BM as the third and fourth component of PBDB‐T:ITCT, leading to simultaneously increased V oc and J sc and maintained fill factor (FF). The guest IT‐T‐IC has upshifted LUMO energy level helping to obtain a higher V oc . The further addition of 0.2 PC71 BM as the fourth component yields an even higher V oc because the LUMO of PC71 BM is higher than that of ITCT. Interestingly, the blend of PC71 BM leads to the formation of an unprecedented neuron‐like morphology, which acts as new centers not only performing light absorption and charge separation but also charge transport through their surrounding donor and acceptor fibers. The increased hole and electron mobilities and the reduced bimolecular loss results in an even larger J sc and FF. These results indicate that a combination using a structurally similar higher‐LUMO‐level non‐fullerene acceptor and PCBM is a simple yet effective quaternary material approach to simultaneously increase V oc and J sc while maintaining FF, improving final device performance. Abstract : A quaternary material system with 12.5%‐efficiency is designed with a structurally similar non‐fullerene plus a fullerene acceptor guest. The synergy between the host and the higher LUMO‐level guests results in increased open circuit voltage and concurrent formation of an unprecedented neuron‐like morphology, which acts as new centers for proceeding excitons generation, separation, and transport with increased short circuit current.