Modulating phase segregation during spin-casting of fullerene-based polymer solar-cell thin films upon minor addition of a high-boiling co-solvent

Lu, K.-H.; Wu, W.-R.; Su, C.-J.; Yang, P.-W.; Yamada, N.L.; Zhuo, H.-J.; Chen, S.-A.; Chuang, W.-T.; Lan, Y.-K.; Su, A.-C.; Jeng, U.-S.

doi:10.1107/S1600576724010082

Figure 9
(a) Time-resolved, in-plane GISAXS profiles selectively extracted at q_z = 0.05 Å⁻¹ from the corresponding 2D GISAXS patterns in Fig. 8

(a), measured during spin-coating of the CB solution of PTB7/PC₇₁BT, without DIO. The thick and curved arrows indicate the growth and decay of the intensity in the very low q region (<0.001 Å⁻¹) during the early (t₁), intermediate (t₁–t₂) and late (t > t₃) spin-coating stages. The thin long arrow indicates the growth and saturation of the SD peak at q_y ≃ 0.002 Å⁻¹. (b) Selected in-plane GISAXS profiles extracted at q_z = 0.025 Å⁻¹ (see Fig. S6 for details) for the film processed with 1.5% DIO. Data at t = 4, 48, 78 and 98 s are selectively fitted (solid curves) using a sphere model of radii of 53 ± 8, 56 ± 4, 60 ± 4 and 58 ± 3 nm, respectively. (c) The growth behaviors of Q_inv (extracted from the corresponding time-resolved in-plane GISAXS profiles) during spin-coating of the PTB7–PC₇₁BM films from the CB solutions, with the DIO concentrations indicated. (d) Time-dependent film thickness h (top) and film thinning rate dh/dt (bottom) measured using UV–Vis reflectance during film spin-coating without and with 3% DIO. The horizontal dotted lines label the constant-evaporation regions. The shaded zone marks the timing of SD in (a).

JOURNAL OF
APPLIED
CRYSTALLOGRAPHY

ISSN: 1600-5767

Volume 57| Part 6| December 2024| Pages 1871-1883

https://doi.org/10.1107/S1600576724010082

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