Presentation Information
[9p-E201-4]Elucidation of the three-dimensional orientation of P3HT domains in OPV active layers and its correlation with compositional distribution
〇Shin Inamoto1, Chizuru Asahara1, Fumiya Uehara1 (1.Toray Research Center)
Keywords:
Organic Photovoltaics,electron microscope,time-of-flight secondary ion mass spectrometry
We investigated the three-dimensional nanostructure and compositional distribution in organic photovoltaic (OPV) active layers using a combination of differential phase-contrast scanning transmission electron microscopy (DPC-STEM) tomography and gas cluster ion beam time-of-flight secondary ion mass spectrometry (GCIB-TOF-SIMS). A bulk heterojunction film composed of poly(3-hexylthiophene) (P3HT) and PCBM was fabricated by spin coating followed by thermal annealing. Tilt-series DPC-STEM images (±76°, 4° increments) were reconstructed into a 3D volume, revealing that P3HT forms plate-like domains predominantly oriented perpendicular to the film plane. Near the surface, the domains exhibit a tendency toward more parallel alignment. Depth profiling by GCIB-TOF-SIMS showed an increased P3HT concentration in the surface region compared to the bulk. These results suggest a correlation between molecular orientation and compositional distribution. The combined approach provides a powerful, complementary method for elucidating 3D morphology and composition in OPV active layers, offering insights into structure–performance relationships.