XRD1 Highlights

Molecular orientations in homojunction organic solar cells

This work highlights the importance of understanding the orientation and packing of small molecules used in organic solar cells, as the energy levels are not only defined by the molecular structure itself, but that molecular orientation plays a crucial role in the overall performance of the device. Y. Dong et al., Nat Commun 11, 4617 (2020)

Organic solar cells (OSCs) made significant progress towards commercialization in recent years, due to a steady increase in efficiency and stability. One important aspect of solar cells in general is the efficient generation of free charges by illumination. In this work efficient organic solar cells with a homojunction, comprising only a single material, α-sexithiophene (α-6T) were investigated. It was shown that, the presence of two types of domains with different molecular orientation in the α-6T layer is the main reason behind the efficient charge generation in these solar cell devices. We used this x-ray technique to confirm the presence of the two different domain types in our films and were able to show that in one of these the molecules adopt a lying down geometry whereas in the other type they are standing upright (relative to the substrate).

This work highlights the importance of understanding the orientation and packing of small molecules used in organic solar cells, as the energy levels are not only defined by the molecular structure itself, but that molecular orientation plays a crucial role in the overall performance of the device. Retrieve Article Orientation dependent molecular electrostatics drives efficient charge generation in homojunction organic solar cells Dong Y., Nikolis V. C., Talnack F., Chin Y., Benduhn J., Londi G., Kublitski J., Zheng X., Mannsfeld S. C. B., Spoltore D., Muccioli L., Li J., Blase X., Beljonne D., Kim J., Bakulin A. A., D’Avino G., Durrant J. R., Vandewal K. Nat Commun 11, 4617 (2020) DOI: 10.1038/s41467-020-18439-z