In case of more hydrophobic photocatalysts, such as conjugated polymers , use of an immersion ultrasonicator may be needed. In this case, the immersed sonotrode supplies the ultrasonic vibrations directly to the photocatalyst mixture, which enables efficient dispersion. Figures show the dispersion of highly hydrophobic poly-(1,3,5-triethynylbenzene) using this technique. In this case, the sample was ultrasonicated three times for five minutes each, supplying 200 W of sonication power. In between the ultrasonication treatments, the sample was vortexed, to disperse any photocatalyst particles that got stuck to the upper parts of the glass vial. When using such high sonication powers, it is important to cool the sample using ice water to avoid excessive heating of the sample. The full list of the equipment used for dispersion of the photocatalyst is listed in Supplementary Table .