Cross-conjugated n-type polymer acceptors for efficient all-polymer solar cells

Abstract

We designed and synthesized a series of n-type cross-conjugated polymers with a donor-π-bridge-acceptor structure (D-π-bridge-A) which can be used as electron-accepting materials to construct efficient all-polymer solar cells (all-PSCs). The two-dimensional architecture allows for the formation of cross-conjugation, which is favorable for charge carrier transport and light harvesting. Bulk-heterojunction all-PSCs based on these cross-conjugated electron-accepting polymers and PTB7-Th as the electron-donating polymer achieve an impressive power conversion efficiency of 5.55%. This cross-conjugated architecture provides a new molecular design strategy for n-type conjugated polymers.

Recent Advances, Design Guidelines, and Prospects of All-Polymer Solar Cells

“… ,,,− ​ Our discussion starts from the observation that P­(NDI2OD-T2) is still one of the best-performing P A s in all-PSCs. In most cases where the molecular structures of NDI-based P A s are largely modified from the P­(NDI2OD-T2), we noted that the PCEs of the corresponding all-PSCs generally decreased. ,− ,− For example, successful NDI-based P A s have rarely been reported in which the bithiophene (T2) units in P­(NDI2OD-T2) were replaced by bulkier electron-donating units. The resulting all-PSC PCEs mostly remained lower than 5% (see Table ) because the incorporation of the bulky moieties into NDI-based P A s not only disrupts the planar backbone conformation of the original P­(NDI2OD-T2), but also hinders close contact with P D s. Consequently, such molecular design strategies have often deteriorated the superior electron transport of P­(NDI2OD-T2) and impeded efficient exciton dissociation at the P D – P A interfaces.…”

A Rational Design and Synthesis of Cross-Conjugated Small Molecule Acceptors Approaching High-Performance Fullerene-Free Polymer Solar Cells

“…47 More recently, our group reported a family of NDI-based cross-conjugated polymer acceptors consisting of donor−acceptor main chain with pendant acceptor groups at the end of the side chains. The device fabricated with these NDI-based acceptors and the polymer PTB7-Th as the electron donor exhibited a best power conversion efficiency of 5.55%, 48 which showed the feasibility and great potential of the strategy for designing highperformance non-fullerene acceptors.…”

“…Cross-conjugation was developed as an efficient strategy for the design of both the donors and acceptors for OSCs in our previous work. , Polymeric donors PFDCN and PFPDT featured an electron-rich conjugated backbone, and the cross-conjugated side chain exhibited photovoltaic properties with a PCE as high as 4.74% using PCBM as the acceptor in a conventional device . More recently, our group reported a family of NDI-based cross-conjugated polymer acceptors consisting of donor–acceptor main chain with pendant acceptor groups at the end of the side chains.…”

Pillar[5]arene-based supramolecular gel: construction and applications

“…[5][6][7][8] To date, SGs have contributed to enormous progress in the emerging field of soft materials. [9][10][11][12][13][14] Pillar[n]arenes, regarded as a novel kind of significant artificial synthetic macrocycle, were first discovered by Ogoshi in 2008. Because pillar [n]arenes possess rigorous pillar-shaped backbones and can be prepared easily, they have received considerable attention in the area of supramolecular chemistry, presenting enormous potential in multidisciplinary integration progress. [15][16][17][18] In general, pillar [5]arene has served as the starting point for pillar [n]arenes and has been synthesized via the Friedel-Crafts (F-C) alkylation of 1,4-dialkoxybenzenes with bridging methylene groups at the 2-position and 5-position, resulting in a yield of nearly 80%.…”

“…5–8 To date, SGs have contributed to enormous progress in the emerging field of soft materials. 9–14…”