Acceptor–Donor–Acceptor type ionic molecule materials for efficient perovskite solar cells and organic solar cells. (December 2016)

• Record Type: Journal Article
• Authors: Cheng, Ming; Aitola, Kerttu; Chen, Cheng; Zhang, Fuguo; Liu, Peng; Sveinbjörnsson, Kári; Hua, Yong; Kloo, Lars; Boschloo, Gerrit; Sun, Licheng
• Is Part Of: Nano energy. Volume 30(2016:Dec.)
• Page Start: 387
• Page End: 397
• Publication Date: 2016-12
• Subjects: Perovskite solar cell -- Organic solar cell -- Hole transport material -- Donor material; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2016.10.041
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Perovskite solar cells (PSCs) have attracted significant interest and hole transporting materials (HTMs) play important roles in achieving high efficiency. Here, we report additive free ionic type HTMs that are based on 2-ethylhexyloxy substituted benzodithiophene (BDT) core unit. With the ionization of end-capping pyridine units, the hole mobility and conductivity of molecular materials are greatly improved. Applied in PSCs, ionic molecular materialM7-TFSI exhibits the highest efficiency of 17.4% in the absence of additives [lithium bis(trifluoromethanesulfonyl)imide and 4- tert -butylpyridine]. The high efficiency is attributed to a deep highest occupied molecular orbital (HOMO) energy level, high hole mobility and high conductivity ofM7-TFSI . Moreover, due to the higher hydrophobicity ofM7-TFSI, the corresponding PSCs showed better stability than that of Spiro-OMeTAD based ones. In addition, the strong absorption and suitable energy levels of materials (M6, M7-Br andM7-TFSI ) also qualify them as donor materials in organic solar cells (OSCs) and the devices containingM7-TFSI as donor material displayed an efficiency of 6.9%. Graphical abstract: Highlights: New ionic molecular materials were designed and synthesized for photovoltaic applications. Applied in PSCs as HTMs, M7-TFSI based device achieved the highest efficiency of 17.4%. OSCs employingM7-TFSI as donor material obtained an efficiency of 6.9%.