Slot‐Die‐Coated Organic Solar Cells Optimized through Multistep Crystallization Kinetics

Abstract

To fabricate organic solar cells (OSCs) via slot‐die coating, solvent additives are essential to induce an optimized phase‐separated and order morphology. It is critical to determine the morphological evolution from solution to solid state and understand the crystallization kinetics in slot‐die coating. Using in situ grazing‐incidence wide‐angle X‐ray scattering characterization, the morphological evolution in PM6‐ and ITIC‐based systems without or with 0.3% 1,8‐diiodooctane (DIO) as additive can be monitored in real‐time during slot‐die coating. As a result, DIO weakens the planarization of the PM6 backbone and splits the backbone ordering into fragments to form ordered crystallites. DIO also induces surface crystallization to reinforce the tie‐chain connections between the crystallites. Furthermore, in the ITIC system, DIO triggers the formation of an interconnected fibril network morphology and concurrently promotes the stacking of ITIC molecules in between the polymer network. Thus, an optimized morphology with a refined crystal structure is formed with the help of DIO. As a result, the power conversion efficiency is improved from 8.77% to 9.59% in slot‐die‐coated OSCs. These findings provide guidelines for optimizing the morphology in slot‐die‐coated OSCs and accelerate the transition of laboratory‐scale fabrication to industrial production.

The Molecular Ordering and Double‐Channel Carrier Generation of Nonfullerene Photovoltaics within Multi‐Length‐Scale Morphology

“…With the crystal's orientation, the simulation results can help us to label the crystal planes on the major diffraction spots of the 2D GIWAXS patterns from experiment. 1,8-diodoctane (DIO) [17,18] is used as the additive to manipulate film formation and changed the morphology. It is seen that using DIO improves the ordering of NFA molecules, showing stronger GIWAXS diffraction signals, which originate from slower drying or solvent vapor annealing for deposited thin films.…”

Fluorination-Induced Conversion of the Quasi- to the Normal Interchain Packing in Push–Pull Conjugated Polymer Aggregates

“…To investigate the effect of fluorination of the 2-ethylhexyl thiophene side group of the BDT unit on CP chain conformation within the aggregates, we obtained Raman spectra (Figure S3 and Tables S3 and S4 in the Supporting Information) and two-dimensional grazing-incidence X-ray diffraction (2D GI-XRD) patterns/profiles of the CP thin films (Figures S4–S6 and Table S5). Detailed analyses are described in the Nanostructure Characterization of the CP Thin Films section in the Supporting Information. ,− …”

Sequentially N‐Doped Acceptor Primer Layer Facilitates Electron Collection of Inverted Non‐Fullerene Organic Solar Cells

“…In turn, these remnants could serve as the more oriented nucleation sites to guide and promote the domain growth in the BHJ active layers. [ 61–63 ] Figure 3h provides a schematic summary of the above argumentation.…”