Strongly Reduced Non-Radiative Voltage Losses in Organic Solar Cells Prepared with Sequential Film Deposition

Hui Kang; Xuning Zhang; Xiaoyun Xu; Yanxun Li; Shilin Li; Qian Cheng; Liqing Huang; Yanan Jing; Huiqiong Zhou; Zaifei Ma; Yuan Zhang

doi:10.1021/acs.jpclett.1c02323

Strongly Reduced Non-Radiative Voltage Losses in Organic Solar Cells Prepared with Sequential Film Deposition

J Phys Chem Lett. 2021 Nov 4;12(43):10663-10670. doi: 10.1021/acs.jpclett.1c02323. Epub 2021 Oct 27.

Authors

Hui Kang¹, Xuning Zhang¹, Xiaoyun Xu², Yanxun Li³, Shilin Li¹, Qian Cheng³, Liqing Huang¹, Yanan Jing¹, Huiqiong Zhou³, Zaifei Ma², Yuan Zhang¹

Affiliations

¹ School of Chemistry, Beihang University, Beijing 100191, China.
² State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
³ National Center for Nanoscience and Technology, Beijing 100191, China.

PMID: 34704764
DOI: 10.1021/acs.jpclett.1c02323

Abstract

With nearly 100% yields for mobile charge carriers in organic solar cells (OSCs), the relatively large photovoltage loss (ΔV_oc) is a critical barrier limiting the power conversion efficiency of OSCs. Herein, we aim to improve the open-circuit voltage (V_oc) in OSCs with non-fullerene acceptors via sequential film deposition (SD). We show that ΔV_oc in planar heterojunction (PHJ) devices prepared by the SD method can be appreciably mitigated, leading increases in V_oc to 80 mV with regard to the V_oc of bulk heterojunction devices. In PHJ OSCs, the energy level of intermolecular charge-transfer states is found to increase with a decrease in the level of aggregation in the solid state. These properties explain the enhanced electroluminescent quantum efficiency and resultant suppression of the voltage losses induced by nonradiative charge recombination and interfacial charge transfer. This work provides a promising strategy for tackling the heavily discussed photovoltage loss in OSCs.