Effects of thiophene substituents on hole-transporting properties of dipolar chromophores for perovskite solar cells

• Published in: Journal of materials science Vol. 53; no. 9; pp. 6626 - 6636
• Main Authors: Cui, Jianyu, Rao, Wei, Hu, Weixia, Zhang, Zemin, Shen, Wei, Li, Ming, He, Rongxing
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2018; Springer; Springer Nature B.V
• Subjects: Absorption spectra; Analysis; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromophores; Classical Mechanics; Computation; Crystallography and Scattering Methods; Electrochemical analysis; First principles; Hole mobility; Material properties; Materials Science; Perovskite; Perovskites; Photovoltaic cells; Polymer Sciences; Red shift; Solar batteries; Solar cells; Solid Mechanics; Thiophene; Transportation
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-017-1810-2

We present a theoretical investigation of thiophene substituent effects on the electrochemical properties of dipolar chromophores (TCNE, TCNE22 and TCNE24) as hole-transporting materials (HTMs) in perovskite solar cells (PSCs). Herein, the material properties in crystalline phases are explored by using the first-principle calculations combined with Marcus theory. The results show that the increased number of thiophene substituents for TCNE, TCNE22 and TCNE24 results in a redshift of the absorption spectrum (27–46 nm). Furthermore, both TCNE22 and TCNE24 have maximum absorption peaks at a wavelength of 400 nm. Most importantly, the molecular planarity is improved effectively, which generates strong intermolecular face-to-face π – π packing interaction. The higher hole mobility of TCNE24 (2.069 × 10 −1  cm 2  V −1  s −1 ) with four thiophene substituents is obtained due to the face-to-face π – π packing. The new designed TCNE24 not only has excellent spectral property, but also has strong hole mobility. Therefore, TCNE24 is a promising organic small-molecule HTMs. Our work provides theoretical guidance for designing higher-performance HTMs in PSCs.