On the Role of PTB7‐Th:[70]PCBM Blend Concentration in ortho‐Xylene on Polymer Solar‐Cell Performance. Issue 12 (6th September 2017)

• Record Type: Journal Article
• Authors: Salamandra, Luigi; La Notte, Luca; Paronesso, Giorgia; Susanna, Gianpaolo; Cinà, Lucio; Polino, Giuseppina; Mattiello, Leonardo; Catini, Alexandro; Di Natale, Corrado; Martinelli, Eugenio; Di Carlo, Aldo; Brunetti, Francesca; Brown, Thomas M.; Reale, Andrea
• Is Part Of: Energy technology. Volume 5:Issue 12(2017:Dec.)
• Page Start: 2168
• Page End: 2174
• Publication Date: 2017-09-06
• Subjects: additives -- energy conversion -- polymers -- solar cells -- surface morphology; Energy development -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1002/ente.201700237
• Languages: English
• ISSNs: 2194-4288

Abstract

Abstract: The use of low‐band‐gap polymers as donors is a new approach to realize high‐efficiency polymer solar cells. Among the low bandgap polymers, poly{4, 8‐bis[5‐(2‐ethylhexyl)thiophen‐2‐yl]benzo[1, 2‐ b ;4, 5‐ b ′]dithiophene‐2, 6‐diyl‐ alt ‐[4‐(2‐ethylhexyl)‐3‐fluorothieno[3, 4‐ b ]thiophene]‐2‐carboxylate‐2‐6‐diyl} (PTB7‐Th) is one of the most promising candidates, thanks to the possibility of exploiting deposition protocols (technique, solvent, concentration) from the most‐known poly{[4, 8‐bis(2‐ethylhexyloxy)benzo(1, 2‐ b :4, 5‐ b ′)dithiophene]‐2, 6‐diyl‐ alt ‐[4‐(2‐ethylhexyl)‐3‐fluorothieno[3, 4‐ b ]thiophene]‐2‐carboxylate‐2‐6‐diyl} (PTB7) and the fact that it shows a power conversion efficiency (PCE) exceeding 10 %. In this paper, we focus on the role of the ink concentration for film deposition and the formation of the active layer. The effect of the solid content (PTB7‐Th:[70]PCBM; [70]PCBM=[6, 6]‐phenyl‐C71 ‐butyric acid methyl ester) in an ortho ‐xylene‐based solution on the performance of the polymer solar cell was investigated. Further, a correlation between the solid content and the1, 8‐diiodooctane additive in the ink formulation with respect to device performance was discussed. A remarkable PCE of 8.2 % was demonstrated. Abstract : Inking a deal : To realize inverted polymer solar cells based on PBT7‐Th:[70]PCBM in ortho ‐xylene with high performance (>8 %), the solid content of the ink has to be calibrated to obtain an optimal active layer in both thickness and surface morphology at the interface with hole‐transport layer. A special warning of the role of 1, 8‐diiodooctane in the process has to be taken into account.