Deuteration-enhanced neutron contrasts to probe amorphous domain sizes in organic photovoltaic bulk heterojunction films.
Guilong CaiYuhao LiYuang FuHua YangLe MeiZhaoyang NieTengfei LiHeng LiuYubin KeXun-Li WangJean-Luc BredasMan-Chung TangXian-Kai ChenXiaowei ZhanXinhui LuPublished in: Nature communications (2024)
An organic photovoltaic bulk heterojunction comprises of a mixture of donor and acceptor materials, forming a semi-crystalline thin film with both crystalline and amorphous domains. Domain sizes critically impact the device performance; however, conventional X-ray scattering techniques cannot detect the contrast between donor and acceptor materials within the amorphous intermixing regions. In this study, we employ neutron scattering and targeted deuteration of acceptor materials to enhance the scattering contrast by nearly one order of magnitude. Remarkably, the PM6:deuterated Y6 system reveals a new length scale, indicating short-range aggregation of Y6 molecules in the amorphous intermixing regions. All-atom molecular dynamics simulations confirm that this short-range aggregation is an inherent morphological advantage of Y6 which effectively assists charge extraction and suppresses charge recombination as shown by capacitance spectroscopy. Our findings uncover the amorphous nanomorphology of organic photovoltaic thin films, providing crucial insights into the morphology-driven device performance.
Keyphrases
- solar cells
- room temperature
- molecular dynamics simulations
- ionic liquid
- solid state
- water soluble
- magnetic resonance
- high resolution
- dna damage
- molecular docking
- molecular dynamics
- particulate matter
- signaling pathway
- cancer therapy
- magnetic resonance imaging
- single molecule
- computed tomography
- mass spectrometry
- quantum dots