High‐Performing Polycarbazole Derivatives for Efficient Solution‐Processing of Organic Solar Cells in Air. Issue 24 (10th December 2015)

• Record Type: Journal Article
• Authors: Burgués‐Ceballos, Ignasi; Hermerschmidt, Felix; Akkuratov, Alexander V.; Susarova, Diana K.; Troshin, Pavel A.; Choulis, Stelios A.
• Is Part Of: ChemSusChem. Volume 8:Issue 24(2015:Dec.)
• Page Start: 4209
• Page End: 4215
• Publication Date: 2015-12-10
• Subjects: copolymers -- photovoltaics -- solar cells -- solution processing -- upscaling; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201501128
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: The application of conjugated materials in organic photovoltaics (OPVs) is usually demonstrated in lab‐scale spin‐coated devices that are processed under controlled inert conditions. Although this is a necessary step to prove high efficiency, testing of promising materials in air should be done in the early stages of research to validate their real potential for low‐cost, solution‐processed, and large‐scale OPVs. Also relevant for approaching commercialization needs is the use of printing techniques that are compatible with upscaling. Here, solution processing of organic solar cells based on three new poly(2, 7‐carbazole) derivatives is efficiently transferred, without significant losses, to air conditions and to several deposition methods using a simple device architecture. High efficiencies in the range between 5.0 % and 6.3 % are obtained in (rigid) spin‐coated, doctor‐bladed, and (flexible) slot‐die‐coated devices, which surpass the reference devices based on poly[ N ‐9′‐heptadecanyl‐2, 7‐carbazole‐ alt ‐5, 5‐(4′, 7′‐di‐2‐thienyl‐2′, 1′, 3′‐benzothiadiazole)] (PCDTBT). In contrast, inkjet printing does not provide reliable results with the presented polymers, which is attributed to their high molecular weight. When the device area in the best‐performing system is increased from 9 mm 2 to 0.7 cm 2, the efficiency drops from 6.2 % to 5.0 %. Photocurrent mapping reveals inhomogeneous current generation derived from changes in the thickness of the active layer. Abstract : Fabricate them in air : A series of poly(2, 7‐carbazole) derivatives are used to fabricate organic solar cells in air using roll‐to‐roll‐compatible deposition methods. High efficiencies are obtained both in rigid and in flexible devices. Initial defects in photocurrent generation are identified when moving from millimeter‐sized to centimeter‐sized devices.