Identifying the Trade-off between Intramolecular Singlet Fission Requirements in Donor-Acceptor Copolymers

Intramolecular singlet fission (iSF) has shown potential to improve the power conversion efficiency in photovoltaic devices by promoting the splitting of a photon-absorbing singlet exciton into two triplet excitons within a single molecule. Among different possibilities, the donor-acceptor modular strategy of copolymers has shown great promise in its ability to undergo iSF under certain conditions. However, the number of iSF donor-acceptor copolymers reported in the literature remains remarkably narrow and clear trends for the molecular design of better candidates have not yet been established. In this work, we identify the trade-off between the main iSF requirements of the donor-acceptor strategy and formulate design rules that allow them to be tuned simultaneously in a fragment-based approach. Based on a library of 2944 donor-acceptor copolymers, we establish simple guidelines to build promising novel materials for iSF. These consist in (1st) selecting an acceptor core with high intrinsic singlet-triplet splitting, (2nd) locating a donor with a larger monomer frontier molecular orbital (FMO) gap than that of the acceptor, and (3rd) tuning the relative energy of donor and/or acceptor FMOs through functionalization to promote photoinduced charge transfer in the resulting polymer. Remarkably, systems containing benzothiadiazole and thiophehe-1,1-dioxide acceptors, which have been shown to undergo iSF, fulfill all criteria simultaneously when paired with appropriate donors. This is due to their particular electronic features, which make them highly promising candidates in the quest for iSF materials.

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Designing Singlet Fission Candidates from Donor-Acceptor Copolymers

10.26434/chemrxiv.11861817 ◽

2020 ◽

Author(s):

Jacob Terence Blaskovits ◽

Maria Fumanal ◽

Sergi Vela ◽

Clemence Corminboeuf

Keyword(s):

High Throughput Screening ◽

Molecular Design ◽

Crystal Packing ◽

Cost Effective ◽

Frontier Molecular Orbital ◽

Structure Property ◽

Singlet Fission ◽

Structure Property Relationships ◽

Large Databases ◽

Donor Acceptor

Singlet Fission (SF) has demonstrated significant promise for boosting the power conversion efficiency (PCE) of solar cells. Traditionally, SF is targeted as an intermolecular process, however its dependence on crystal packing makes molecular design difficult. In contrast, intramolecular SF (iSF) enables the exploration of tunable bi-chromophoric systems following well-defined structure-property relationships. In this work, we propose a set of parameters to screen conjugated donor-acceptor copolymer candidates with potential iSF behaviour. We focus our analysis on the E(S1)>2E(T1) thermodynamic condition and on the appropriate charge transfer (CT) character of S1. We map the CT character with respect to the frontier molecular orbital (FMO) energies of the constituent monomers, providing a cost-effective protocol for an accelerated screening of promising iSF donor-acceptor pairs, while minimizing the number of computations. These parameters are applied to a chemically diverse, curated library of 81 truncated dimers of synthetically feasible donor-acceptor copolymers. From our dataset, four candidates are flagged for iSF, two of which were previously experimentally reported. This protocol is envisioned to be scaled up for the high-throughput screening of large databases of donor-acceptor dimers for the design and identification of conjugated polymers capable of iSF.

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Designing Singlet Fission Candidates from Donor-Acceptor Copolymers

10.26434/chemrxiv.11861817.v1 ◽

2020 ◽

Author(s):

Jacob Terence Blaskovits ◽

Maria Fumanal ◽

Sergi Vela ◽

Clemence Corminboeuf

Keyword(s):

High Throughput Screening ◽

Molecular Design ◽

Crystal Packing ◽

Cost Effective ◽

Frontier Molecular Orbital ◽

Structure Property ◽

Singlet Fission ◽

Structure Property Relationships ◽

Large Databases ◽

Donor Acceptor

Singlet Fission (SF) has demonstrated significant promise for boosting the power conversion efficiency (PCE) of solar cells. Traditionally, SF is targeted as an intermolecular process, however its dependence on crystal packing makes molecular design difficult. In contrast, intramolecular SF (iSF) enables the exploration of tunable bi-chromophoric systems following well-defined structure-property relationships. In this work, we propose a set of parameters to screen conjugated donor-acceptor copolymer candidates with potential iSF behaviour. We focus our analysis on the E(S1)>2E(T1) thermodynamic condition and on the appropriate charge transfer (CT) character of S1. We map the CT character with respect to the frontier molecular orbital (FMO) energies of the constituent monomers, providing a cost-effective protocol for an accelerated screening of promising iSF donor-acceptor pairs, while minimizing the number of computations. These parameters are applied to a chemically diverse, curated library of 81 truncated dimers of synthetically feasible donor-acceptor copolymers. From our dataset, four candidates are flagged for iSF, two of which were previously experimentally reported. This protocol is envisioned to be scaled up for the high-throughput screening of large databases of donor-acceptor dimers for the design and identification of conjugated polymers capable of iSF.

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Designing Singlet Fission Candidates from Donor-Acceptor Copolymers

10.26434/chemrxiv.11861817.v2 ◽

2020 ◽

Author(s):

Jacob Terence Blaskovits ◽

Maria Fumanal ◽

Sergi Vela ◽

Clemence Corminboeuf

Keyword(s):

High Throughput Screening ◽

Molecular Design ◽

Crystal Packing ◽

Cost Effective ◽

Frontier Molecular Orbital ◽

Structure Property ◽

Singlet Fission ◽

Structure Property Relationships ◽

Large Databases ◽

Donor Acceptor

Singlet Fission (SF) has demonstrated significant promise for boosting the power conversion efficiency (PCE) of solar cells. Traditionally, SF is targeted as an intermolecular process, however its dependence on crystal packing makes molecular design difficult. In contrast, intramolecular SF (iSF) enables the exploration of tunable bi-chromophoric systems following well-defined structure-property relationships. In this work, we propose a set of parameters to screen conjugated donor-acceptor copolymer candidates with potential iSF behaviour. We focus our analysis on the E(S1)>2E(T1) thermodynamic condition and on the appropriate charge transfer (CT) character of S1. We map the CT character with respect to the frontier molecular orbital (FMO) energies of the constituent monomers, providing a cost-effective protocol for an accelerated screening of promising iSF donor-acceptor pairs, while minimizing the number of computations. These parameters are applied to a chemically diverse, curated library of 81 truncated dimers of synthetically feasible donor-acceptor copolymers. From our dataset, four candidates are flagged for iSF, two of which were previously experimentally reported. This protocol is envisioned to be scaled up for the high-throughput screening of large databases of donor-acceptor dimers for the design and identification of conjugated polymers capable of iSF.

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Molecular design strategy for practical singlet fission materials: The charm of donor/acceptor decorated quinoidal structure

CCS Chemistry ◽

10.31635/ccschem.021.202101199 ◽

2021 ◽

pp. 1-17

Author(s):

Long Wang ◽

Xiaomei Shi ◽

Shishi Feng ◽

WanZhen Liang ◽

Hongbing Fu ◽

...

Keyword(s):

Molecular Design ◽

Design Strategy ◽

Singlet Fission ◽

Donor Acceptor

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Identifying the Trade-off between Intramolecular Singlet Fission Requirements in Donor–Acceptor Copolymers

Chemistry of Materials ◽

10.1021/acs.chemmater.1c00057 ◽

2021 ◽

Author(s):

J. Terence Blaskovits ◽

Maria Fumanal ◽

Sergi Vela ◽

Raimon Fabregat ◽

Clémence Corminboeuf

Keyword(s):

Singlet Fission ◽

Trade Off ◽

Donor Acceptor

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Site-Specific Protein Covalent Attachment to Nanotubes and Its Electronic Impact on Single Molecule Function

10.26434/chemrxiv.7798973.v1 ◽

2019 ◽

Author(s):

Adam Beachey ◽

Harley Worthy ◽

William David Jamieson ◽

Suzanne Thomas ◽

Benjamin Bowen ◽

...

Keyword(s):

Single Molecule ◽

Fluorescent Protein ◽

Functional Integration ◽

Attachment Site ◽

Covalent Attachment ◽

Great Promise ◽

Functional Coupling ◽

Phenyl Azide ◽

Electronic Impact ◽

Protein Attachment

Functional integration of proteins with carbon-based nanomaterials such as nanotubes holds great promise in emerging electronic and optoelectronic applications. Control over protein attachment poses a major challenge for consistent and useful device fabrication, especially when utilizing single/few molecule properties. Here, we exploit genetically encoded phenyl azide photochemistry to define the direct covalent attachment of three different proteins, including the fluorescent protein GFP, to carbon nanotube side walls. Single molecule fluorescence revealed that on attachment to SWCNTs GFP’s fluorescence changed in terms of intensity and improved resistance to photobleaching; essentially GFP is fluorescent for much longer on attachment. The site of attachment proved important in terms of electronic impact on GFP function, with the attachment site furthest from the functional center having the larger effect on fluorescence. Our approach provides a versatile and general method for generating intimate protein-CNT hybrid bioconjugates. It can be potentially applied easily to any protein of choice; attachment position and thus interface characteristics with the CNT can easily be changed by simply placing the phenyl azide chemistry at different residues by gene mutagenesis. Thus, our approach will allow consistent construction and modulate functional coupling through changing the protein attachment position.

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