Appropriate Molecular Interaction Enabling Perfect Balance Between Induced Crystallinity and Phase Separation for Efficient Photovoltaic Blends

Abstract

Fluorination is a promising modification method to adjust the photophysical profiles of organic semiconductors. Notably, the fluorine modification on donor or acceptor materials could impact the molecular interaction, which is strongly related to the morphology of bulk heterojunction (BHJ) blends and the resultant device performance. Therefore, it is essential to investigate how the molecular interaction affects the morphology of BHJ films. In this study, a new fluorinated polymer PBDB-PSF is synthesized to investigate the molecular interaction in both nonfluorinated (ITIC) and fluorinated (IT-4F) systems. The results reveal that the F–F interaction in the PBDB-PSF:IT-4F system could effectively induce the crystallization of IT-4F while retaining the ideal phase separation scale, resulting in outstanding charge transport. On the contrary, poor morphology can be observed in the PBDB-PSF:ITIC system because of the unbalanced molecular interaction. As a consequence, the PBDB-PSF:IT-4F device delivers an excellent power conversion efficiency of 13.63%, which greatly exceeds that of the PBDB-PSF:ITIC device (9.84%). These results highlight manipulating the micromorphology with regard to molecular interaction.

Rational Mutual Interactions in Ternary Systems Enable High‐Performance Organic Solar Cells

“…As indicated in Figure 3d, the intense emission peak of PM6 at 650 nm is largely quenched in binary and ternary systems, suggesting the excitons of the donor could be efficiently dissociated by the acceptor. [49] Notably, the residual fluorescence in PM6:LA9 blend was out of the emission range of PM6, which could be originated from PL emission of LA9 located between 700 and 850 nm. This observation probably correlates with the overly aggregated PM6:LA9 blend and thus insufficient contact surface between the donor and acceptor.…”

The Crystallinity Control of Polymer Donor Materials for High-Performance Organic Solar Cells

“…Even for the same polymer, a slight variation in the processing conditions can lead to different crystallinity values. In BHJ OSCs, both polymer and small molecules possess large conjugated regions and therefore induce crystallinity in the system (Jiang et al, 2020). The source of crystallinity usually determines its influencing factors upon a certain system.…”

Effect of ethylene glycol and its derivatives on the aggregation properties of reactive Orange 13 dye aqueous solution

“…Research on the aggregate structure of dyes especially in favourable areas like solar power generation (cyanine dyes), [1][2][3][4] dyeing and printing [5][6][7][8] has always remained a hot topic for researchers to work on so that a number of problems can be eliminated. In particular, the aggregation behaviour of dyes creates a problem in the preparation of homogeneous dye solutions or inks for dyeing and printing of different textile substrates through affecting the process of dye adsorption and diffusion.…”