Influence of the processing solvent on the photoactive layer nanomorphology of P3HT/PC₆₀BM solar cells

Abstract

In this article, it is demonstrated that doctor blading of thin poly-3-hexylthiophene/phenyl-C 61 -butyric acid methyl ester (1/1) bulk-hetero junction films from toluene leads to an improved nanocrystallinity, when compared with their unannealed chlorobenzene processed counterparts. This difference in morphology was demonstrated by solid-state NMR and Rapid Heating Cooling Calorimetry (RHC), being useful complementary techniques to investigate the active layer morphology of photovoltaic devices. An increased PC 60 BM nanocrystallinity is indi-cated by several NMR relaxation decay times (T 1C , T 1H , and T 1qH ) and confirmed by an increase of the melting enthalpy in RHC experiments. An improved solar cell performance further strengthens this conclusion. V C 2011 Wiley Periodicals, Inc.

Probing the bulk heterojunction morphology in thermally annealed active layers for polymer solar cells

“…It can be expected that in actual OPV active layers the initial structure formation or nucleation, leading to large-scale effects during annealing, will be caused by the preparation of the active layer from a solvent. The effect of different solution processing methodologies on the crystals formed in P3HT/PC61BM mixtures has been documented before [17,19,28,69], and the present study represents an important step towards a fundamental understanding of these observations.…”

Solvent inkjet printing process for the fabrication of polymer solar cells

“…2,8 The common solution deposit techniques applied in PSCs are spin coating, doctor blading and so on. 2,[8][9][10] However, the spin coating or blading processes are not ideal techniques for exploring the full potential for the production of PSCs due to waste products, environmental pollution and difficulties in patterning. Moreover, spin coating and doctor blading are not roll-to-roll production when preparing flexible PSCs.…”

How to measure absolute P3HT crystallinity via 13C CPMAS NMR

“…Despite its ubiquitous use in solving problems related to biology, chemistry, and materials science, solid‐state nuclear magnetic resonance (NMR) has had relatively little impact in the field of organic electronics (OE). Indeed, despite the prevalent use of the technique in the physical sciences, the number of recent publications where solid‐state NMR was utilized to solve critical problems in, for instance, organic photovoltaics remains quite low . This remains true even though the technique could be used to potentially solve several critical issues that face this field.…”