An Oligothiophene–Fullerene Molecule with a Balanced Donor–Acceptor Backbone for High‐Performance Single‐Component Organic Solar Cells

Wang, Wei; Sun, Rui; Guo, Jing; Guo, Jin; Min, Jie

doi:10.1002/anie.201908232

Cited by 68 publications

(87 citation statements)

References 48 publications

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“…[ 10 ] Very recently, Min and coworkers reported a D–A dyad consisting of a benzodithiophene‐cored oligothiophene, which was linked to a PC 71 BM fullerene by a 12‐atom spacer, reaching a PCE of 3.22%. [ 13 ] These results indicate that well‐chosen spacers can be favorable elements for D–A systems in SMOSCs by facilitating favorable lamellar nanophase separation of D and A units. We recently developed a D–A dyad comprising a dithienopyrrol (DTP)‐cored oligomeric donor, which was covalently linked to PC 61 BM through a ten‐atom alkyl ester spacer, and reported a PCE of 3.4% in SMOSCs.…”

Section: Introductionmentioning

confidence: 95%

Molecular Donor–Acceptor Dyads for Efficient Single‐Material Organic Solar Cells

et al. 2020

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Dedicated to Professor Franz Effenberger on the occasion of his 90th birthday 1. Introduction Covalently linked donor-acceptor (D-A) dyads, triads, and multiads have been extensively investigated in the context of photoinduced energy and charge transfer (CT) processes, which are fundamental for natural photosynthesis, but as well important for the function of organic solar cells. [1,2] The nature and length of the molecular spacer bridging D and A, flexible nonconjugated or rod-like conjugated, polar or nonpolar, play an important role for the various fundamental processes such as excitation and energy transfer, CT, charge separation, and recombination. [3] CT is also dependent on the environment, [4] which severely comes into play for the photoinduced elementary processes of molecular D-A systems in the solid state, a scenario, encountered in organic electronic devices. In this respect, in thin films, aggregation of the molecules into supramolecular assemblies to form photoactive nanostructures with well-segregated A and D domains and their orientation relative to the substrate play a major role for efficient organic solar cells. [5] As a consequence, the tailoring of molecular properties in D-A systems is an important aspect in the overall structural design for tuning and controlling distance-dependent CT, whereby intermolecular interactions and self-assembly determine charge separation in thin films. The understanding and Single-material organic solar cells (SMOSCs) promise several advantages with respect to prospective applications in printed large-area solar foils. Only one photoactive material has to be processed and the impressive thermal and photochemical long-term stability of the devices is achieved. Herein, a novel structural design of oligomeric donor-acceptor (D-A) dyads 1-3 is established, in which an oligothiophene donor and fullerene acceptor are covalently linked by a flexible spacer of variable length. Favorable optoelectronic, charge transport, and self-organization properties of the D-A dyads are the basis for reaching power conversion efficiencies up to 4.26% in SMOSCs. The dependence of photovoltaic and charge transport parameters in these ambipolar semiconductors on the specific molecular structure is investigated before and after post-treatment by solvent vapor annealing. The inner nanomorphology of the photoactive films of the dyads is analyzed with transmission electron microscopy (TEM) and grazingincidence wide-angle X-ray scattering (GIWAXS). Combined theoretical calculations result in a lamellar supramolecular order of the dyads with a D-A phase separation smaller than 2 nm. The molecular design and the precise distance between donor and acceptor moieties ensure the fundamental physical processes operative in organic solar cells and provide stabilization of D-A interfaces.

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Section: Introductionmentioning

confidence: 95%

Molecular Donor–Acceptor Dyads for Efficient Single‐Material Organic Solar Cells

et al. 2020

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“…[4] In contrast, singlecomponent OSCs (SCOSCs) have been somehow ignored by researchers in the past two decades,a lthough they have exhibited superior stability that is ap rerequisite for real applications. [5] Single-component conjugated materials contain diblock conjugated polymers, [6] double-cable conjugated polymers, [7] and molecular dyads, [8] but most of them were limited to polythiophene derivatives.T he widely developed donor-acceptor conjugated polymers [9] and non-fullerene acceptors [10] have been rarely incorporated into the singlecomponent materials.A nother drawback is the difficulty to obtain the optimized phase separation between donor and acceptor segments in as ingle material, resulting in severe charge recombination and low charge transport efficiency. As ac onsequence,S COSCs showed the highest PCE of 6.3 % that was far lagging behind two-component OSCs.…”

Section: Introductionmentioning

confidence: 99%

Miscibility‐Controlled Phase Separation in Double‐Cable Conjugated Polymers for Single‐Component Organic Solar Cells with Efficiencies over 8 %

et al. 2020

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Arecordpower conversion efficiency of 8.40 %was obtained in single-component organic solar cells (SCOSCs) based on double-cable conjugated polymers.T his is realized based on exciton separation playing the same role as charge transport in SCOSCs.T wo double-cable conjugated polymers were designed with almost identical conjugated backbones and electron-withdrawing side units,b ut extra Cl atoms had different positions on the conjugated backbones.W hen Cl atoms were positioned at the main chains,the polymer formed the twist backbones,e nabling better miscibility with the naphthalene diimide side units.T his improves the interface contact between conjugated backbones and side units,resulting in efficient conversion of excitons into free charges.T hese findings reveal the importance of charge generation process in SCOSCs and suggest as trategy to improve this process: controlling miscibility between conjugated backbones and aromatic side units in double-cable conjugated polymers.

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“…[9] A popular strategy to explore electron and energy transfer is to construct the donor-linker-acceptor (D-L-A) systems. [10] For most reported D-L-A molecules, the donor moieties often exhibit one emission band due to a single emissive state, which is the single channel for electron and/or energy transfer. Herein, the dual emissive DPAC originating from bent and planar excited states was utilized as dual-channel donors to establish new D-L-A systems, in which the excitedstate bent to planar structure relaxation can be used as a clock in clocking as well as harnessing the electron/energy transfer processes.…”

Section: Introductionmentioning

confidence: 99%

Diversified Excited‐State Relaxation Pathways of Donor–Linker–Acceptor Dyads Controlled by a Bent‐to‐Planar Motion of the Donor

et al. 2020

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Herein, we introduce the cyclic 8p-electron (C8p) molecule N,N'-diaryl-dihydrodibenzo[a,c]phenazine (DPAC) as a dual-functional donor to establish a series of new donorlinker-acceptor (D-L-A) dyads DLA1-DLA5. The excitedstate bent-to-planar dynamics of DPAC regulate the energy gap of the donor, while the acceptors A1-A5 are endowed with different energy gaps and HOMO/LUMO levels. As a result, the rate and efficiency of the excited-state electron transfer vs. energy transfer can be finely harnessed, which is verified via steady-state spectroscopy and time-resolved emission measurements. This comprehensive approach demonstrates, for the first time, the manifold of excited-state properties governed by bifunctional donor-based D-L-A dyads, including bent-toplanar, photoinduced electron transfer (PET) from excited donor to acceptor (oxidative-PET), fluorescence resonance energy transfer (FRET), bent-to-planar followed by electron transfer (PFET), and PET from donor to excited acceptor (reductive-PET).

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An Oligothiophene–Fullerene Molecule with a Balanced Donor–Acceptor Backbone for High‐Performance Single‐Component Organic Solar Cells

Cited by 68 publications

References 48 publications

Molecular Donor–Acceptor Dyads for Efficient Single‐Material Organic Solar Cells

Molecular Donor–Acceptor Dyads for Efficient Single‐Material Organic Solar Cells

Miscibility‐Controlled Phase Separation in Double‐Cable Conjugated Polymers for Single‐Component Organic Solar Cells with Efficiencies over 8 %

Diversified Excited‐State Relaxation Pathways of Donor–Linker–Acceptor Dyads Controlled by a Bent‐to‐Planar Motion of the Donor

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