Ternary Organic Solar Cells with Minimum Voltage Losses. Issue 21 (20th July 2017)

• Record Type: Journal Article
• Authors: Wang, Chuanfei; Zhang, Wei; Meng, Xiangyi; Bergqvist, Jonas; Liu, Xianjie; Genene, Zewdneh; Xu, Xiaofeng; Yartsev, Arkady; Inganäs, Olle; Ma, Wei; Wang, Ergang; Fahlman, Mats
• Is Part Of: Advanced energy materials. Volume 7:Issue 21(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-07-20
• Subjects: binary equivalent -- minimum voltage losses -- same bulk and interface energy -- ternary solar cells; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201700390
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: A new strategy for designing ternary solar cells is reported in this paper. A low‐bandgap polymer named PTB7‐Th and a high‐bandgap polymer named PBDTTS‐FTAZ sharing the same bulk ionization potential and interface positive integer charge transfer energy while featuring complementary absorption spectra are selected. They are used to fabricate efficient ternary solar cells, where the hole can be transported freely between the two donor polymers and collected by the electrode as in one broadband low bandgap polymer. Furthermore, the fullerene acceptor is chosen so that the energy of the positive integer charge transfer state of the two donor polymers is equal to the energy of negative integer charge transfer state of the fullerene, enabling enhanced dissociation of all polymer donor and fullerene acceptor excitons and suppressed bimolecular and trap assistant recombination. The two donor polymers feature good miscibility and energy transfer from high‐bandgap polymer of PBDTTS‐FTAZ to low‐bandgap polymer of PTB7‐Th, which contribute to enhanced performance of the ternary solar cell. Abstract : Ternary solar cells with minimum voltage losses around 0.25 eV are designed by combining two donor polymers with same bulk and interface energy which make the hole transportation like in one donor polymer. The voltage losses were minimized due to E ICT+ ≈ E ICT−, where the trade‐off between enhancing of charge generation and charge recombination by ICT states arrives at sweet spot.