Joule
Volume 4, Issue 8, 19 August 2020, Pages 1790-1805
Journal home page for Joule

Article
Selective Hole and Electron Transport in Efficient Quaternary Blend Organic Solar Cells

https://doi.org/10.1016/j.joule.2020.06.014Get rights and content
Under an Elsevier user license
open archive

Highlights

  • Quaternary blend organic solar cells (q-OSCs) achieve 17.73%

  • Quaternary blend systems with a unique “rivers and streams”-type morphology

  • q-OSCs significantly outperforms the corresponding binary and ternary devices

  • q-OSCs, via careful selection of materials, offer unprecedented prospects for OSCs

Context & Scale

One important strategy to further enhance the efficiency of organic solar cells (OSCs) is to incorporate three or even four complementary organic materials in one cell. Such OSCs (often referred to as ternary or quaternary OSCs) can offer much broader absorption, thus better performance because one single organic material typically has a narrow absorption band. Despite the benefits, material selection and morphology control are extremely challenging for ternary OSCs already, while quaternary OSCs are not even considered feasible practically. In this manuscript, we have successfully developed a new type of quaternary blend system, which exhibits a unique “rivers and streams”-type hierarchical morphology that allows it to operate exceptionally efficiently, reaching a high PCE of 17.73%, significantly outperforming the corresponding binary and ternary devices. This type of “rivers and streams” morphology can offer unprecedented opportunities for organic solar cells with better efficiency.

Summary

Multi-component organic solar cells (OSCs) comprising more than two donor and acceptor materials have attracted significant research attention, as they can offer broader and better absorption, hence increasing solar cell performance. However, the morphology of multi-component OSCs is exceptionally complicated and challenging to control. Here, we develop a highly efficient (near 17.7%) quaternary OSC (q-OSC) using two polymer donors (namely PM6 and PTQ10) along with a fullerene (PC71BM) and a non-fullerene acceptor (N3). Our quaternary system demonstrates a new type of “rivers and streams” functional hierarchical (multi-length scale) morphology, where small domains of PTQ10 and PC71BM act as separators that spatially separate PM6 and N3, which effectively suppressed charge recombination, enhanced hole transport, and balanced charge transportation. These improvements in the quaternary system contribute to the increased internal quantum efficiency (IQE) and, thus, lead to an excellent JSC and device performance, which surpass their respective binary and ternary OSCs.

Keywords

quaternary blend organic solar cells
bulk heterojunction
functional hierarchical morphology
charge transport
charge recombination
fullerene acceptor
non-fullerene acceptor
multi-length scale morphology

Cited by (0)

10

These authors contributed equally

11

Lead Contact