Constructing D-π-A Type Polymers as Dopant-Free Hole Transport Materials for High-Performance CsPbI2Br Perovskite Solar Cells

Zheng Dai; Qiang Guo; Yuanjia Ding; Zhibin Wang; Naizhong Jiang; Erjun Zhou

doi:10.1021/acsami.2c23036

Constructing D-π-A Type Polymers as Dopant-Free Hole Transport Materials for High-Performance CsPbI₂Br Perovskite Solar Cells

ACS Appl Mater Interfaces. 2023 Feb 9. doi: 10.1021/acsami.2c23036. Online ahead of print.

Authors

Zheng Dai^{1

2}, Qiang Guo¹, Yuanjia Ding^{1

2}, Zhibin Wang³, Naizhong Jiang³, Erjun Zhou^{1

2}

Affiliations

¹ Henan Institute of Advanced Technology, School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450003, China.
² National Center for Nanoscience and Technology, Beijing 100190, China.
³ College of Physics and Energy, Fujian Normal University, Fuzhou 350117, China.

PMID: 36757325
DOI: 10.1021/acsami.2c23036

Abstract

Hole-transporting materials (HTMs) play a major role in efficient and stable perovskite solar cells (PSCs), especially for CsPbI₂Br inorganic PSC. Among them, dopant-free conjugated polymers attract more attention because of the advantages of high hole mobility and high stability. However, the relationship between the polymer structure and the photovoltaic performance is rarely investigated. In this work, we choose three similar D-π-A-type polymers, where the D unit and π-bridge are fixed into benzodithiophene and thiophene, respectively. By changing the A units from classic benzodithiophene-4,8-dione and benzotriazole to quinoxaline, three polymers PBDB-T, J52, and PE61 are utilized as dopant-free HTMs for CsPbI₂Br PSCs. The energy levels, hole mobility, and molecular stacking of the three HTMs, as well as charge transfer between CsPbI₂Br/HTMs, are fully investigated. Finally, the device based on PE61 HTM obtains the champion power conversion efficiency of 16.72%, obviously higher than PBDB-T (15.13%) and J52 (15.52%). In addition, the device based on PE61 HTM displays the best long-term stability. Those results demonstrate that quinoxaline is also an effective A unit to construct D-π-A-type polymers as HTMs and improve the photovoltaic performance of PSCs.

Keywords: D-π-A-type polymers; dopant-free; hole transport materials; perovskite solar cells; power conversion efficiency.