Stronger Coupling of Quantum Dots in Hole Transport Layer Through Intermediate Ligand Exchange to Enhance the Efficiency of PbS Quantum Dot Solar Cells

Yuyao Wei; Chao Ding; Guozheng Shi; Huan Bi; Yusheng Li; Hua Li; Dong Liu; Yongge Yang; Dandan Wang; Shikai Chen; Ruixiang Wang; Shuzi Hayase; Taizo Masuda; Qing Shen

doi:10.1002/smtd.202400015

Stronger Coupling of Quantum Dots in Hole Transport Layer Through Intermediate Ligand Exchange to Enhance the Efficiency of PbS Quantum Dot Solar Cells

Small Methods. 2024 Apr 12:e2400015. doi: 10.1002/smtd.202400015. Online ahead of print.

Authors

Yuyao Wei¹, Chao Ding², Guozheng Shi^{1

3}, Huan Bi¹, Yusheng Li¹, Hua Li¹, Dong Liu¹, Yongge Yang¹, Dandan Wang¹, Shikai Chen¹, Ruixiang Wang⁴, Shuzi Hayase¹, Taizo Masuda^{1

5}, Qing Shen¹

Affiliations

¹ Faculty of Informatics and Engineering, The University of Electro Communications, Tokyo, 1828585, Japan.
² Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu, 610065, P. R. China.
³ Institution of Functional Nano and Soft Materials, Soochow university, Suzhou, Jiangsu, 215123, P. R. China.
⁴ Beijing Engineering Research Centre of Sustainable Energy and Buildings, Beijing University of Civil Engineering and Architecture, Beijing, 102616, P. R. China.
⁵ CN development division, Toyota Motor Corporation, Susono, Shizuoka, 410-1193, Japan.

PMID: 38607951
DOI: 10.1002/smtd.202400015

Abstract

Nowadays, the extensively used lead sulfide (PbS) quantum dot (QD) hole transport layer (HTL) relies on layer-by-layer method to replace long chain oleic acid (OA) ligands with short 1,2-ethanedithiol (EDT) ligands for preparation. However, the inevitable significant volume shrinkage caused by this traditional method will result in undesired cracks and disordered QD arrangement in the film, along with adverse increased defect density and inhomogeneous energy landscape. To solve the problem, a novel method for EDT passivated PbS QD (PbS-EDT) HTL preparation using small-sized benzoic acid (BA) as intermediate ligands is proposed in this work. BA is substituted for OA ligands in solution followed by ligand exchange with EDT layer by layer. With the new method, smoother PbS-EDT films with more ordered and closer QD packing are gained. It is demonstrated stronger coupling between QDs and reduced defects in the QD HTL owing to the intermediate BA ligand exchange. As a result, the suppressed nonradiative recombination and enhanced carrier mobility are achieved, contributing to ≈20% growth in short circuit current density (J_sc) and a 23.4% higher power conversion efficiency (PCE) of 13.2%. This work provides a general framework for layer-by-layer QD film manufacturing optimization.

Keywords: PbS quantum dot (QD); hole transport layer (HTL); ligand exchange; solar cell.

Abstract

Grants and funding