Using light-induced thermocleavage in a roll-to-roll process for polymer solar cells

We report on the use of intense visible light with a narrow spectral distribution matched to the region where the conjugated polymer material absorbs to selectively heat the active material and induce thermocleavage. We show a full roll-to-roll process, leading to complete large-area polymer solar cell modules using light-induced thermocleavage. The process employs full solution processing in air for all five layers in the device and does not employ indium-tin oxide or vacuum processing. The process steps were carefully analyzed using X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, attenuated total reflectance infrared, and transmission/reflection UV-vis techniques.