Alkyl side chain engineering for difluorinated benzothiadiazole flanked non-fullerene acceptors toward efficient polymer solar cells

Impact of substituents on the performance of small-molecule semiconductors in organic photovoltaic devices via regulating morphology

“…Additionally, Chen et al reported a related study with ID–benzothiadiazole–rhodanine conjugates 7-13a and 7-13b . 137 In this case, again, substitution with more extended alkyl chains (octyl) on the ID core adequately attenuated self-aggregation and phase separation when compared to more compact (hexyl) alkyl chains in BHJ films. Accordingly, higher photovoltaic performance resulted from 7-13b (PCE = 9.4%) than 7-13a (9.1%) in BHJ OPVs with PTB7-Th as the p-type material (entries 7-44 and 7-45).…”

The effect of fluorination on the low and high frequency dielectric constants of non-polymeric organic semiconductors – towards homojunction solar cells

“…A previously reported route used harsh conditions in order to activate the methyl group through double bromination. 43 We used milder bromination conditions to form the mono-bromide 6 in a reasonable yield of ≈77% (note both methyl groups of the impurity introduced in the previous step were also brominated). The bromine groups were then transformed into the corresponding alcohol 7 in a two-step yield of ≈79%.…”

“…The syntheses of the protonated 7-bromo-benzo[c] [1,2,5]thiadiazole-4-carbaldehyde, 9, 33 10, 42 protonated CPDT-BT-Ald 33 and D(CPDT-BT-Ald) 34 have been previously reported. However, while 8 is a reported compound, 43 we were unable to repeat the results for some of the described steps. We therefore include a reproducible synthesis in this work.…”

Recent Progress in the Design of Fused-Ring Non-Fullerene Acceptors─Relations between Molecular Structure and Optical, Electronic, and Photovoltaic Properties

“…Solar cells with PTB7-Th have similar PCE values (up to 9.4% in both cases). 390 The Zhou research group has developed new acceptors based on a benzotriazole spacer (BTA series).…”

“…Fluorination of the BT spacer ( 5-91 , H-FFBR, and 5-92 , O-FFBR) lowers the energy levels compared to 5-79 . Solar cells with PTB7-Th have similar PCE values (up to 9.4% in both cases) . The Zhou research group has developed new acceptors based on a benzotriazole spacer (BTA series).…”