The mechanical flexibility and relatively low cost of organic solar cells (OSCs) enables their use as an integrated power-generating source in niche applications, such as wearable electronics, and in building-integrated photovoltaics that could revolutionise infrastructure design.
Current OSCs use fullerene-based semiconductors as electron acceptors, but the recent development of high-performance non-fullerene acceptors (NFAs) has transformed the research into OSCs. NFAs have recently outperformed their fullerene counterparts in bulk-heterojunction (BHJ) organic solar cells.
In research published in the Journal of Materials Chemistry A, an international team of researchers used neutron reflectivity measurements on the Offspec beamline to investigate the potential of a sequentially deposited BHJ (sq-BHJ) layout using an NFA as the acceptor component. This sq-BHJ layout occurs when the NFA is deposited onto the electron donor layer (usually a polymer), rather than using a co-deposition technique.
Their results show that this layout can offer comparable performance to that measured when co-depositing BHJ, without the need for solvent additives, or post-treating the deposited sample. Their two-step process may have other relevant advantages, including higher stability, large-scale production and green processing. It could therefore be possible, after further investigation, to produce a sq-BHJ system that can be used in practical applications.
Related publication: “Efficient non-fullerene organic solar cells employing sequentially deposited donor–acceptor layers" J. Mater. Chem. A, 2018,6, 18225-18233, DOI: 10.1039/C8TA06860G
Authors: Jiangbin Zhang (University of Cambridge, Imperial College London), Bin Kan (Nankai University), Andrew J. Pearson (University of Cambridge), Andrew J. Parnell (The University of Sheffield), Joshaniel F. K. Cooper (ISIS), Xiao-Ke Liu (University of Cambridge, Linköping University), Patrick J. Conaghan (University of Cambridge), Thomas R. Hopper (Imperial College London), Yutian Wu (University of Cambridge), Xiangjian Wan (Nankai University), Feng Gao (Linköping University), Neil C. Greenham (University of Cambridge), Artem A. Bakulin (Imperial College London), Yongsheng Chen (Nankai University) and Richard H. Friend (University of Cambridge)