A simple spiro-type hole transporting material for efficient perovskite solar cells

• Published in: Energy & environmental science 2015-07, Vol.8 (7), p.1986-1991
• Main Authors: Ganesan, Paramaguru, Fu, Kunwu, Gao, Peng, Raabe, Ines, Schenk, Kurt, Scopelliti, Rosario, Luo, Jingshan, Wong, Lydia H, Graetzel, Michael, Nazeeruddin, Mohammad Khaja
• Format: Article
• Language: English
• Subjects: Crystal structure; Diffraction; Industrial development; Perovskites; Photovoltaic cells; Solar cells; Transporting; X-rays
• ISSN: 1754-5692; 1754-5706
• DOI: 10.1039/c4ee03773a

We developed a cost-effective spiro-type 4,4',4'',4'''\-(2 H,2'H,4H,4' H-3,3'-spiro-bi[thieno[3,4-b][1,4]dioxepine]-6,6',8,8'-tetr ayl)tetrakis(N ,N-bis(4-methoxyphenyl)aniline) hole transporting material (PST1) for perovskite solar cells (PSCs) that works efficiently even without a cobalt dopant. The PST1 is obtained by employing facile synthetic routes and tends to crystallize in the solid state. An X-ray diffraction study of PST1 revealed a unique quasi-spiro molecular configuration and found multiple CH/ pi and pi - pi intermolecular contacts. For the first time, the crystal structure of 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-s p irobifluorene (spiro-OMeTAD) is also studied for comparison. The device based on PST1 exhibited a PCE of 13.44%, and a comparable 12.74% PCE was achieved for its undoped form, which paves the way for developing new low cost hole transporting materials and final industrialization of perovskite solar cells.