Perfluoroalkylfullerenes

Boltalina, Olga V.; Popov, Alexey A.; Kuvychko, Igor V.; Shustova, Natalia B.; Strauss, Steven H.

doi:10.1021/cr5002595

Cited by 92 publications

(111 citation statements)

References 231 publications

(943 reference statements)

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“…[20] Each TMF was extensively purified (see Supporting Information) to ensure no compositional or isomeric impurities were present that could otherwise complicate our interpretation of the observed PCG behavior in the samples, a problem that has been documented for commercially available fullerene acceptors, especially those carrying multiple adducts. We also carefully selected and prepared six different fullerene acceptors from the largest family of well-characterized fullerene derivatives, known as TMFs (i.e.,-C 60 (CF 3 ) n , n = even).…”

Section: Materials Selectionmentioning

confidence: 99%

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Inter‐Fullerene Electronic Coupling Controls the Efficiency of Photoinduced Charge Generation in Organic Bulk Heterojunctions

Larson

Reid

Coffey

et al. 2016

Advanced Energy Materials

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energy and (ii) equally efficient collection of those charges. The former relies on appropriate choice of donor and acceptor materials that balance minimal reorganization energy with optimally aligned energy levels, while the latter principally relies on high hole and electron mobilities in their respective phases. [1] Over the past decade, significant research efforts have been devoted to gaining a better fundamental understanding of the relationship between molecular properties and the photophysics of interfacial and bulk free charge generation and transport in OPV material systems, which has directly led to increases in the performance of these materials by rational design. [2][3][4][5][6] In the case of polymer:fullerene OPVs, the polymer acts as the dominant light absorber and also directs film morphology, which are two crucial tasks for an OPV material. Naturally, a greater amount of effort has gone into understanding how structural, electronic, and physicochemical properties of the polymer affect charge generation photophysics than has been expended for the fullerene. Nonetheless, these systems are inherently bipartite, and, as we show in this report, the properties of the fullerene acceptor should be as carefully considered as those of the polymer for maximizing free carrier generation.We are particularly interested in the question of how local electronic coupling between individual fullerene molecules affects photoinduced charge generation (PCG). Some of the present authors have addressed this question previously, modulating aggregation of either the polymer or the fullerene to control PCG. [7] Here, the electronically coupled donor aggregates (polythiophene crystals) are always present. We investigate the importance of local coupling between fullerenes in high-loading OPV blends containing more complicated bulk heterojunction (BHJ) structures and interfaces, i.e., -those relevant to working devices. The observed high-frequency electron mobility in the fullerene phase is taken as a qualitative measure of the local electronic coupling strength between fullerenes.From an experimental standpoint, this question has been extremely difficult to answer in bulk heterojunction structures because of the large number of variables contributing to PCG Photoinduced charge generation (PCG) dynamics are notoriously difficult to correlate with specific molecular properties in device relevant polymer:fullerene organic photovoltaic blend films due to the highly complex nature of the solid state blend morphology. Here, this study uses six judiciously selected trifluoromethylfullerenes blended with the prototypical polymer poly(3-hexylthiophene) and measure the PCG dynamics in 50 fs-500 ns time scales with time-resolved microwave conductivity and femtosecond transient absorption spectroscopy. The isomeric purity and thorough chemical characterization of the fullerenes used in this study allow for a detailed correlation between molecular properties, driving force, local intermolecular electronic coupling and, ultimately, the ...

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Section: Materials Selectionmentioning

confidence: 99%

“…Energy Mater. [20] The yellow areas in the Schlegel diagram highlight the addition pattern of CF 3 groups (represented by black dots) on the cage. The three pairs of TMFs used in this study are shown, first prepared and described in ref.…”

Section: Pair 3: Constant E 1/2 Different Lumo Shape Different Cagmentioning

confidence: 99%

Inter‐Fullerene Electronic Coupling Controls the Efficiency of Photoinduced Charge Generation in Organic Bulk Heterojunctions

Larson

Reid

Coffey

et al. 2016

Advanced Energy Materials

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“…[8][9][10][11][12][13][14] A remarkable recent example presents a family of mixed derivatives of C 70 with the same eight methoxy groups in the equatorial part of the molecule and different further addends, such as cyclopropane, epoxide, and hydroxide moieties, as efficient fluorophores with peak emission wavelengths spanning the range of 450 to 650 nm. [15] Those polyadducts demonstrate, in particular, strong dependence of the electron affinity values on the addition pattern [16][17][18] while also capable of efficient fluorescence (quantum yields up to 0.68). [15] Those polyadducts demonstrate, in particular, strong dependence of the electron affinity values on the addition pattern [16][17][18] while also capable of efficient fluorescence (quantum yields up to 0.68).…”

Section: Introductionmentioning

confidence: 99%

Regioselective Synthesis of [6,6]‐Open and [5,6]‐Closed C₇₀(CF₃)₈[CH₂] Methanofullerenes with Rapid [6,6]‐to‐[5,6] Phototransformation

et al. 2018

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Fullerene derivatives with >CH2 addends in [6,6]‐open or [5,6]‐closed configuration are uncommon of fullerene derivatives, but they are readily accessible via treatment of Cs‐C70(CF3)8 with diazomethane followed by thermolysis or photolysis. Both thermodynamic and kinetic factors favor regioselective addition of diazomethane at the near‐equatorial [5,6]‐double bond of Cs‐C70(CF3)8 to give a thermally labile pyrazoline intermediate. Thermal extrusion of N2 from the latter is a kinetically controlled process with orbital symmetry controlled Woodward–Hoffmann‐allowed mechanism. It quantitatively yields the less thermodynamically favorable [6,6]‐open isomer of C70(CF3)8[CH2] homofullerene, but the latter turns out to be capable of unexpectedly rapid quantitative phototransformation into the thermodynamically preferable [5,6]‐closed methanofullerene isomer. The transformation involves the manifold of the triplet states that facilitate the required cleavage of the Ccage–CH2 bonds.

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“…In the case of PFAFs, electronic properties are determined mainly by the addition patterns, i.e., positions of R F groups on the cage, and to a lesser extent, by the number of R F groups. Within the same composition, different isomers can span E 1/2 values over a wide range, e.g., 500 mV for C 60 (CF 3 ) 10 isomers …”

Section: Introductionmentioning

confidence: 99%

Fluorous Fullerene Acceptors in Vacuum‐Deposited Photovoltaic Cells

et al. 2019

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The first successful example of vacuum‐deposited organic photovoltaic (OPV) cells based on a fullerene derivative and a small‐molecule donor is reported. A series of thermally robust fluorous fullerene acceptors with experimental gas‐phase electron affinities ranging from 2.8 to 3.3 eV are paired with a new dicyanovinyl thiophene‐based molecular donor to enable direct comparison of their performance in planar and bulk heterojunction architectures in the cells fabricated by vacuum deposition. Unprecedented insights into the role of the acceptor intrinsic molecular and electronic structures are obtained, which are not obscured by solvent and additive effects as in the typical solution‐processed fullerene‐based OPV cells.

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Perfluoroalkylfullerenes

Cited by 92 publications

References 231 publications

Inter‐Fullerene Electronic Coupling Controls the Efficiency of Photoinduced Charge Generation in Organic Bulk Heterojunctions

Inter‐Fullerene Electronic Coupling Controls the Efficiency of Photoinduced Charge Generation in Organic Bulk Heterojunctions

Regioselective Synthesis of [6,6]‐Open and [5,6]‐Closed C₇₀(CF₃)₈[CH₂] Methanofullerenes with Rapid [6,6]‐to‐[5,6] Phototransformation

Fluorous Fullerene Acceptors in Vacuum‐Deposited Photovoltaic Cells

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Perfluoroalkylfullerenes

Cited by 92 publications

References 231 publications

Inter‐Fullerene Electronic Coupling Controls the Efficiency of Photoinduced Charge Generation in Organic Bulk Heterojunctions

Inter‐Fullerene Electronic Coupling Controls the Efficiency of Photoinduced Charge Generation in Organic Bulk Heterojunctions

Regioselective Synthesis of [6,6]‐Open and [5,6]‐Closed C70(CF3)8[CH2] Methanofullerenes with Rapid [6,6]‐to‐[5,6] Phototransformation

Fluorous Fullerene Acceptors in Vacuum‐Deposited Photovoltaic Cells

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Regioselective Synthesis of [6,6]‐Open and [5,6]‐Closed C₇₀(CF₃)₈[CH₂] Methanofullerenes with Rapid [6,6]‐to‐[5,6] Phototransformation