Pseudo-bilayer architecture enables high-performance organic solar cells with enhanced exciton diffusion length

Kui Jiang,Harald Ade,Yuzhong Chen,Zonglong Zhu,Francis Lin,He Yan,Alex K.-Y Jen,Jie Zhang,Zhengxing Peng,Shengfan Wu,Zhen Li

doi:10.1038/s41467-020-20791-z

Abstract

Solution-processed organic solar cells (OSCs) are a promising candidate for next-generation photovoltaic technologies. However, the short exciton diffusion length of the bulk heterojunction active layer in OSCs strongly hampers the full potential to be realized in these bulk heterojunction OSCs. Herein, we report high-performance OSCs with a pseudo-bilayer architecture, which possesses longer exciton diffusion length benefited from higher film crystallinity. This feature ensures the synergistic advantages of efficient exciton dissociation and charge transport in OSCs with pseudo-bilayer architecture, enabling a higher power conversion efficiency (17.42%) to be achieved compared to those with bulk heterojunction architecture (16.44%) due to higher short-circuit current density and fill factor. A certified efficiency of 16.31% is also achieved for the ternary OSC with a pseudo-bilayer active layer. Our results demonstrate the excellent potential for pseudo-bilayer architecture to be used for future OSC applications.

Highlights

Solution-processed organic solar cells (OSCs) are a promising candidate for next-generation photovoltaic technologies
The exciton diffusion length increased from 7.53 nm in the bulk heterojunction (BHJ) architecture to 17.07 nm in the PB architecture, which should be attributed to the longer coherence length (CL) of the aggregates in the PB films benefited the exciton dissociation in the PB OSCs
In this work, the PB film based on PM6:N3:phenyl-C71-butyric acid methyl ester (PC71BM) was fabricated through the sequential deposition (SD) processing method

Summary

Introduction

Solution-processed organic solar cells (OSCs) are a promising candidate for next-generation photovoltaic technologies. The PB devices based on PM6:Y6-O:PC71BM exhibited a high PCE of 17.27% and achieved a certified PCE of 16.31%, which is the highest performance reported so far for PB OSCs. These results show the correlation between active layer architecture, charge transport, and performance in highefficiency PB OSCs, and demonstrate its potential in further improving OSC performance.

Results

Conclusion