Assessing alkyl side chain effects on electron transport properties of Y6-derived non-fullerene acceptors

Abstract

Recent non-fullerene acceptor (NFA) advancements have propelled organic photovoltaics efficiency to ≈ 20% in single junction solar cells, thanks to the introduction of the very promising L8-R series, obtained by...

Towards a fast machine-learning-assisted prediction of the mechanoelectric response in organic crystals

“…2). We used the last 10 ns of each simulation to evaluate transfer integrals J 1 (for one dimer) and J 2 (for one dimer) and their fluctuations, extracting snapshots every 50 ps, cropping side chains after the first carbon atom, so as to leave the DNBDT core substituted with methyl groups, in analogy to our previous works 50,75 and to what similarly done by others, 76–78 before running DFT computations of transfer integrals. This results in 200 evaluations of each transfer integral, at each strain.…”

“…On the other side, ML models require ad hoc procedures to check the consistency of the sign of the coupling, 75,84 a built-in feature of other methods. 91,92 As suggested by Wang, 84 our ML model was trained on the absolute value of transfer integrals | J |, and the signs were kept consistent with the ones computed in the crystal from first principles.…”

Fast Nonradiative Decay Paths in Organic Solar Cells: Implications for Designing More Efficient Photovoltaic Systems

“…The high planarity of the π-system also improves charge carrier mobility by promoting delocalization and intermolecular stacking. Among the various members of this family, the small molecule indicated as DTS (Figure ) led to a remarkable PCE up to 8.9% in blends with PC70BM. − More recently, further PCE improvements have been obtained by the introduction of nonfullerene acceptors (NFAs), molecules formed by fused-ring structures composed of donor and acceptor moieties, which offer better stability and tunability than fullerenes. − The first NFA, created by Zhan’s team, with an A-D-A structure, led to PCEs up to 13%; , higher efficiencies were attained with the introduction of acceptors having A-D-A′-D-A structures, in particular Y6, see Figure , which yielded a PCE higher than 18% for single-junction OSCs. , …”

Simulation Design of Novel Non-Fluorine Polymers as Electron Transport Layer for Lead-Free Perovskite Solar Cells

“…Designing a non-fullerene-based (NFA) electron transport layer might potentially overcome the drawbacks of the fullerene-based electron transport layer. The stability, tuneability, and optical absorption can all be improved by easily adjusting the chemical molecular structure, highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital (LUMO) of a non-fullerene-based electron transport layer over a reasonably wide range [23][24][25]. The design of NFAs that are reported often falls into one of two categories.…”