Thieno[3,4‐c]pyrrole‐4,6‐dione‐3,4‐difluorothiophene Polymer Acceptors for Efficient All‐Polymer Bulk Heterojunction Solar Cells

Abstract

Branched-alkyl-substituted poly(thieno[3,4-c]pyrrole-4,6-dione-alt-3,4-difluorothiophene) (PTPD[2F]T) can be used as a polymer acceptor in bulk heterojunction (BHJ) solar cells with a low-band-gap polymer donor (PCE10) commonly used with fullerenes. The "all-polymer" BHJ devices made with PTPD[2F]T achieve efficiencies of up to 4.4 %. While, to date, most efficient polymer acceptors are based on perylenediimide or naphthalenediimide motifs, our study of PTPD[2F]T polymers shows that linear, all-thiophene systems with adequately substituted main chains can also be conducive to efficient BHJ solar cells with polymer donors.

Efficient Near‐Infrared Electroluminescence at 840 nm with “Metal‐Free” Small‐Molecule:Polymer Blends

“…The solution was prepared in a 10 mm path quartz cuvette with an absorbance of <0.15 at the lowest energy absorption maximum, following a protocol reported in the literature. [57] excellent spectral overlap with the BTT* absorption (and much better than for F8BT [34] ). Remarkably, PIDT-2TPD exhibits PLQY = 18 ± 3%, which is comparatively high for this spectral range, considering that half of the photons are emitted in the NIR (Table 1).…”

“…However, two caveats must be taken into account: first, the essentially complete delocalization of the frontier orbitals might be due to the tendency of B3LYP functional to overestimate the energy barrier of rotational torsion and thus the planarity of the backbone, [56,57] and second, HOMO and LUMO charge distributions might be different in the solid-state compared the ideal gas-phase conditions of the DFT calculations (see the Supporting Information for further details). According to our calculations, however, by blending BTT* in the two different polymers, we should obtain bulk heterojunctions exhibiting a type-I bandgap alignment.…”

Thieno[3,4‐c]Pyrrole‐4,6‐Dione‐Based Polymer Acceptors for High Open‐Circuit Voltage All‐Polymer Solar Cells

“…[36,[43][44] In the design of polymer donors for high-efficiency BHJ solar cells with PCBM acceptors, distinct side chain patterns can induce significant variations in BHJ morphology and intermolecular interactions between donor and acceptor counterparts; [36] turning to polymer acceptors, those effects may also play an important role and influence material performance. Given that both TPD [36][37][38][39][40][41][42][43][44][45][46][47] and 3,4-difluorothiophene ([2F]T) [48][49][54][55] motifs can effectively increase the IP and EA values when involved in polymer main chains, the combination of these two units along the same backbone can be thought of as a relevant design approach to fullerene alternatives. [ [56][57][58][59] The calculations were performed at the tuned ωB97X-D/6-31G(d,p) level of theory, which ensures a robust description of wavefunction localization / delocalization effects along extended -conjugated chains.…”

“…[49] In this contribution, we report on the design approach, material properties and efficiencies in BHJ solar cells of a set of two analogous TPD/[2F]T-based polymer acceptors -with a specific look on how the introduction of a third electron-deficient motif, namely 2,1,3-benzothiadiazole (BT), [50][51][52] can impact the optical, electronic and charge transport properties of the corresponding …”

8.0% Efficient All‐Polymer Solar Cells with High Photovoltage of 1.1 V and Internal Quantum Efficiency near Unity

“…The high-performance all-PSCs with PCEs over 7% only afford moderate V oc around 0.8 V, [18,22,24,26,28] whereas a few all-PSCs can emerge high V oc around 1.0 V, but the PCEs never surpass 7%. [20,[29][30][31][32] In contrast, a PC 71 BM-based PSC with a high V oc close to 1 V and a high PCE of 8.9% has been realized. [33] A nonfullerene PSC based on a polymer/small molecule blend also attained a high V oc of 1.12 V with a high PCE approaching 10%.…”