Central π-core engineering of non-fullerene small molecule acceptors (NF-SMAs) is effective in boosting the performance of organic solar cells (OSCs). Especially, selenium (Se) functionalization of NF-SMAs is conside...
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Central π-core engineering of non-fullerene small molecule acceptors (NF-SMAs) is effective in boosting the performance of organic solar cells (OSCs). Especially, selenium (Se) functionalization of NF-SMAs is considered a promising strategy but the structure-performance relationship remains unclear. Here, we synthesize two isomeric alkylphenyl-substituted selenopheno[3,2-b]thiophene-based NF-SMAs named mPh4F-TS and mPh4F-ST with different substitution positions, and contrast them with the thieno[3,2-b]thiophene-based analogue, mPh4F-TT. When placing Se atoms at the outer positions of the π-core, mPh4F-TS shows the most red-shifted absorption and compact molecular stacking. The PM6 : mPh4F-TS devices exhibit excellent absorption, high charge carrier mobility, and reduced energy loss. Consequently, PM6 : mPh4F-TS achieves more balanced photovoltaic parameters and yields an efficiency of 18.05 %, which highlights that precisely manipulating selenium functionalization is a practicable way toward high-efficiency OSCs.
Ti/Al 2O 3 composite with improved mechanical properties was synthesized by th e spark plasma sintering. The effect of Nb on the microstructure of the composit e was analyzed by TEM, SEM and so on. The experimental ...
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Ti/Al 2O 3 composite with improved mechanical properties was synthesized by th e spark plasma sintering. The effect of Nb on the microstructure of the composit e was analyzed by TEM, SEM and so on. The experimental results indicate that the bending strength, fracture toughness, micro-hardness and relative density of t he composite are 897.29MPa, 17.38MPa·m 1/2, 17.13GPa and 99.24% respec tively when adding 1.5vol%Nb. The bending strength is improved by reason of form ing dislocation ring and transfering fracture mode from intergranular to mixture fracture of intergranular and transgranular. The crack propagating is mainly th e deflection bridging. It indicates a reduction of crack driving force and an in crease in crack growth resistance,which results in toughness enhanced.
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