A Thieno[3,4-c]pyrrole-4,6-dione-Based Donor−Acceptor Polymer Exhibiting High Crystallinity for Photovoltaic Applications

Alkyl side-chain branching point effects in thieno[3,4-c]pyrrole-4,6-dione copolymers

“…Stille polymerisation whilst versatile and reliable affords number-average molecular weights (M n ) below 10 kDa (Table 1), as has been observed with those reported for similar copolymers. [26,29] It may be possible to achieve higher molecular weights by direct heteroarylation polymerisations. [28] Optical properties.…”

“…In common with previous studies, the (100), (200) and (300) diffraction peaks dominate the spectra making indefinite any (010) peak, associable with facial π-π stacking between polymeric backbones. [29] The difference in XRD patterns mean the polymers are organised differently in the solid state and as such the differences in optical absorption spectra and DSC thermograms are unlikely to be attributed to variations in molecular weight. The increase in solid-state crystallinity for P3 may be attributed to a reduction in side-chain steric bulk (as opposed to length), promoting crystallisation of the polymer.…”

“…[21] Such alkylated TPD-2T polymers have achieved efficiencies as high as 7.3% in BHJ photovoltaic cells and field-effect transistors exhibit hole mobilities as high as 0.6 cm 2 /V s. [22][23][24][25][26][27] In addition, these polymers have recently been reported with both economic and green syntheses. [28,29] Here, we report a novel and efficient synthesis of the TPD unit facilitating late-stage alkylation by haloalkanes and direct C-H activation polymerisation. Four novel TPD-2T polymers with different branching points in the N −alkyl side-chain are prepared (Chart 1) and their optical (UV-VIS) and thermal (differential scanning calorimetry (DSC)) properties, molecular models and X-ray diffraction (XRD) data presented.…”

Incremental optimization in donor polymers for bulk heterojunction organic solar cells exhibiting high performance

“…100-200 nm in diameter), the presence of uniform phase segregation and the absence of large REVIEW domains explained the higher PCE observed for the latter. 78 Similarly, when 3.0% DIO was used as an additive in PTB7/ PC 71 BM devices, active layer processed from CB showed a huge increment in the PCE (3.92 ! 7.40%) compared to DCB (3.92 !…”

“…7.3%). 59,78 Similarly, devices based on the active layer from isoindigo-based polymer (P3TI) and PC 71 BM that was processed with 2.5% (v/v) DIO in DCB resulted in a much finer phase separation compared to devices without the additive. This resulted in an enhanced J SC (10.5 !…”