Side-Chain Engineering of Donor-Acceptor Conjugated Small Molecules As Dopant-Free Hole-Transport Materials for Efficient Normal Planar Perovskite Solar Cells

Bao Tu; Yang Wang; Wei Chen; Bin Liu; Xiyuan Feng; Yudong Zhu; Kun Yang; Zheng Zhang; Yongqiang Shi; Xugang Guo; Hai-Feng Li; Zikang Tang; Aleksandra B Djurišić; Zhubing He

doi:10.1021/acsami.9b17386

Side-Chain Engineering of Donor-Acceptor Conjugated Small Molecules As Dopant-Free Hole-Transport Materials for Efficient Normal Planar Perovskite Solar Cells

ACS Appl Mater Interfaces. 2019 Dec 26;11(51):48556-48563. doi: 10.1021/acsami.9b17386. Epub 2019 Dec 16.

Authors

Bao Tu^{1

2}, Yang Wang¹, Wei Chen^{1

3}, Bin Liu¹, Xiyuan Feng^{1

2}, Yudong Zhu^{1

4}, Kun Yang¹, Zheng Zhang¹, Yongqiang Shi¹, Xugang Guo¹, Hai-Feng Li², Zikang Tang², Aleksandra B Djurišić³, Zhubing He¹

Affiliations

¹ Department of Materials Science and Engineering, Shenzhen Key Laboratory of Full Spectral Solar Electricity Generation (FSSEG) , Southern University of Science and Technology , No. 1088, Xueyuan Rd. , Shenzhen 518055 , Guangdong , China.
² Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering , University of Macau , Avenida da Universidade , Taipa , Macau SAR 999078 , China.
³ Department of Physics , University of Hong Kong , Pokfulam , Hong Kong SAR 999077 , China.
⁴ Department of Electronic and Computer Engineering , Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong SAR 999077 , China.

PMID: 31786921
DOI: 10.1021/acsami.9b17386

Abstract

Simultaneously improving efficiency and stability, which are particularly crucial factors for the commercialization of perovskite solar cells (PSCs), remains a major challenge. For high-efficiency normal PSCs, the development of stable dopant-free hole-transport materials (HTMs) seems imperative. Here, we developed potential donor-acceptor small molecules (BTTI) as HTMs for normal planar PSCs. Through tailoring its alkyl side-chain length as BTTI-C6, BTTI-C8, and BTTI-C12, our results show that upon shortening the side chain of BTTI, the hole mobility, film-forming capability, and resultant device performance were remarkably improved, with the device conversion efficiencies of 19.69% for BTTI-C6, 18.89% for BTTI-C8, and 17.49% for BTTI-C12. Meanwhile, compared to those made with the routine doped Spiro-OMeTAD, devices based on our dopant-free HTMs exhibited significantly improved stability. This work paves the way to the development of effective dopant-free HTMs for high-performance PSCs.

Keywords: donor−acceptor conjugated small molecules; dopant-free; hole-transport materials; perovskite solar cells; side-chain engineering.