Real-time views of morphological evolution in solution-processed organic photovoltaics

Abstract

The nanoscale morphology of the photoactive layer in solution-processed organic photovoltaics plays a critical role in device performance. Such intricate morphology is sensitive to the processing condition during film formation....

Layer-by-layer blade-coated organic solar cells with non-halogenated solvents and non-halogenated additive via adjusting morphology and crystallization

“…The evolution of the Y6 characteristic peak position was tracked with film formation time and four stages were identified: (1) solvent evaporation stage, where the Y6 peak position does not change; (2) weak redshift of the peak position, representing the molecule nucleation stage as the solvent evaporates to reach the critical point of material saturation solubility; (3) significant redshift of the peak position, representing the molecular crystal growth stage as the solvent continues to evaporate beyond the saturation solubility; (4) stable peak position, representing the film formation stage as the solvent completely evaporates and the molecular crystal growth ends. 31–35 Fig. S2 (ESI†) shows that Y6 undergoes nucleation and crystal growth once in the blade-coated Y6( o -XY) film with the evaporation of o -XY; while Y6 undergoes nucleation and crystal growth twice in the blade-coated Y6( o -XY + DMN) film, first with the evaporation of the primary solvent o -XY and partial DMN additive, and second with the further evaporation of the higher boiling point DMN additive.…”