In Operando GISAXS and GIWAXS Stability Study of Organic Solar Cells Based on PffBT4T‐2OD:PC₇₁BM with and without Solvent Additive

Abstract

Solvent additives are known to modify the morphology of bulk heterojunction active layers to achieve high efficiency organic solar cells. However, the knowledge about the influence of solvent additives on the morphology degradation is limited. Hence, in operando grazing‐incidence small and wide angle X‐ray scattering (GISAXS and GIWAXS) measurements are applied on a series of PffBT4T‐2OD:PC 71 BM‐based solar cells prepared without and with solvent additives. The solar cells fabricated without a solvent additive, with 1,8‐diiodoctane (DIO), and with o ‐chlorobenzaldehyde (CBA) additive show differences in the device degradation and changes in the morphology and crystallinity of the active layers. The mesoscale morphology changes are correlated with the decay of the short‐circuit current J sc and the evolution of crystalline grain sizes is codependent with the decay of open‐circuit voltage V oc . Without additive, the loss in J sc dominates the degradation, whereas with solvent additive (DIO and CBA) the loss in V oc rules the degradation. CBA addition increases the overall device stability as compared to DIO or absence of additive.

Revealing Donor–Acceptor Interaction on the Printed Active Layer Morphology and the Formation Kinetics for Nonfullerene Organic Solar Cells at Ambient Conditions

“…To model the lateral structures, cylindrical and spherical objects with different radii are used in the framework of the distorted wave Born approximation (DWBA) assuming the effective interface approximation (EIA). [ 39 ] The DWBA and EIA‐based modeling results are shown in Figure 2 b–d. The average large‐size domain radii of neat PDTBT2T‐FTBDT, BTP‐4F, and PDTBT2T‐FTBDT: BTP‐4F blend films are (100 ± 5) nm, (77 ± 6) nm, and (90 ± 9) nm when using CB, while they are (108 ± 5) nm, (118 ± 5) nm, and (109 ± 4) nm in case of CF.…”

Layer-by-Layer Spray-Coating of Cellulose Nanofibrils and Silver Nanoparticles for Hydrophilic Interfaces

“…To analyze the GISAXS data based on real-space morphological features, we fit the horizontal line cuts with a model assuming cylindrical shapes for CNF-related nanostructures and spherical shapes for AgNP-related nanostructures . The used GISAXS fit model has been proven by literature. − The radius R and center-to-center distance D of these model shapes (cylinders and spheres) were varied in the fit. This model enables us to directly compare the parameters of the fitted nanostructures between GISAXS and AFM measurements.…”

State of the Art and Prospects for Halide Perovskite Nanocrystals

“…In situ experiments usually pose additional experimental challenges, e.g ., the necessity of high flux X-ray radiation ( e.g ., via synchrotron access) and transportable experimental setups, detailed knowledge of reaction kinetics, as well as considering damage induced by the high-intensity X-ray beam. In situ and operando studies have already been used heavily on bulk and thin-film materials and offer many possibilities in perovskite NC thin-film analysis including the elucidation of superstructural features. − …”