Triplet excited state properties in variable gap π-conjugated donor–acceptor–donor chromophores

Çekli, Seda; Winkel, Russell W.; Alarousu, Erkki; Mohammed, Omar F.; Schanze, Kirk S.

doi:10.1039/c5sc04578a

Cited by 64 publications

(67 citation statements)

References 52 publications

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“…53 In addition, we have previously assigned this near-IR band to the singlet excited state, because it decays on the same timescales as the fluorescence emission. 19 Similarly, the lifetimes of the near-IR band (black line in Figure S17 for kinetics) of the molecules reported here are found to be 3.78, 1.22, 1.11 and 0.34 ns for O1-O3 and p-TBT, respectively. These lifetimes are in reasonable agreement with those obtained from the fluorescence decays (Table 2), consistent with the assignment of the band to the singlet state.…”

Section: Excited State Properties Uv-visible Absorption Spectroscopysupporting

confidence: 68%

“…49 Herein, the contributions are evaluated as a measure of distance between the excited electrons and Pt atoms (this is important, because of its high spin-orbit coupling constant Pt dominates the spin-orbit coupling). 19 In particular, the increase in Pt contribution to the LUMO is considered as a shorter median distance between the excited electron and the Pt atoms.…”

Section: Excited State Properties Uv-visible Absorption Spectroscopymentioning

confidence: 99%

“…19 The energy gap law correlation is included in Supporting Information ( Figure S16) and the E T values are listed in Table 2 along with the singlet (E S ) and the splitting (∆E S-T ) energies. The triplet energies are found to decrease by approximately 0.1 eV from O1 to p-TBT.…”

Section: Excited State Properties Uv-visible Absorption Spectroscopymentioning

confidence: 99%

“…15 Our group has an ongoing interest in studying the triplet excited state properties of platinum incorporated π-conjugated structures. [16][17][18] Very recently, we investigated the photophysical properties of a series of platinum acetylide containing π-conjugated donoracceptor-donor (DAD) type small molecules 19 and showed that increasing acceptor strength results in localization of the excited state electrons on the acceptor unit which is located distal from the platinum center. As a result, the rate of intersystem crossing decreases with increased extent of charge transfer due to the increased average distance between the acceptor and the platinum.…”

Section: Introductionmentioning

confidence: 99%

“…Steady-state absorption and emission spectroscopy, fluorescence lifetimes measurements, nanosecond transient absorption spectroscopy and the cyclic voltammetry (CV)/differential pulse voltammetry (DPV) measurements were carried out as reported previously. 19 Fluorescence quantum yields and singlet oxygen quantum yields were reported relative to Rhodamine B (ϕ = 0.69) 28 and terthiophene (ϕ ∆ = 0.84) 29 19 To minimize computational cost, solubilizing PBu 3 moieties were replaced with PMe 3 . These truncated molecules are designated with a ', thus O2 becomes O2'.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Oligomer Length on Photophysical Properties of Platinum Acetylide Donor–Acceptor–Donor Oligomers

2016

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We report a systematic study that explores how the triplet excited state is influenced by conjugation length in a series of benzothiadiazole units containing donor-acceptor-donor (DAD)-type platinum acetylide oligomers and polymer. The singlet and triplet excited states for the series were characterized by an array of photophysical methods including steady-state luminescence spectroscopy and femtosecond-nanosecond transient absorption spectroscopy. In addition to the experimental work, a computational study using density functional theory was conducted to gain more information about the structure, composition, and energies of the frontier molecular orbitals. It is observed that both the singlet and triplet excited states are mainly localized on a single donor-acceptor-donor unit in the oligomers. Interestingly, it is discovered that the intersystem crossing efficiency increases dramatically in the longer oligomers. The effect is attributed to an enhanced contribution of the heavy metal platinum in the frontier orbitals (HOMO and LUMO), an effect that leads to enhanced spin-orbit coupling.

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Section: Excited State Properties Uv-visible Absorption Spectroscopysupporting

confidence: 68%

Section: Excited State Properties Uv-visible Absorption Spectroscopymentioning

confidence: 99%

Section: Excited State Properties Uv-visible Absorption Spectroscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Oligomer Length on Photophysical Properties of Platinum Acetylide Donor–Acceptor–Donor Oligomers

2016

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Precisely Defined Conjugated Oligoelectrolytes for Biosensing and Therapeutics

et al. 2019

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Conjugated oligoelectrolytes (COEs) are a relatively new class of synthetic organic molecules with, as of yet, untapped potential for use in organic optoelectronic devices and bioelectronics systems. COEs also offer a novel molecular approach to biosensing, bioimaging, and disease therapy. Substantial progress has been made in the past decade at the intersection of chemistry, materials science and the biological sciences developing COEs and their polymer analogues, namely conjugated polyelectrolytes (CPEs), into synthetic systems with biological and biomedical utility. CPEs have traditionally attracted more attention in arenas of sensing, imaging, and therapy. However, the precisely-defined molecular structures and interactions of COEs offer potential key advantages over CPEs, including higher reliability and fluorescence quantum efficiency, larger diversity of subcellular targeting strategies, and improved selectivity to biomolecules. Here, the unique -and sometimes overlooked -properties of COEs are discussed and the noticeable progress in their use for biological sensing, imaging and therapy is reviewed.Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))

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Limitations and Perspectives on Triplet‐Material‐Based Organic Photovoltaic Devices

et al. 2019

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Organic photovoltaic cells (OPVs) have attracted broad attention and become a very energetic field after the emergence of nonfullerene acceptors. Long-lifetime triplet excitons are expected to be good candidates for efficiently harvesting a photocurrent. Parallel with the development of OPVs based on singlet materials (S-OPVs), the potential of triplet materials as photoactive layers is explored. However, so far, OPVs employing triplet materials in a bulk-heterojunction have not exhibited better performance than S-OPVs. Here, the recent progress of representative OPVs based on triplet materials (T-OPVs) is briefly summarized. Based on that, the performance limitations of T-OPVs are analyzed. The shortage of desired triplet materials with favourable optoelectronic properties for OPVs, the tradeoff between long lifetime and high binding energy of triplet excitons, as well as the low charge mobility in most triplet materials are crucial issues restraining the efficiencies of T-OPVs. To overcome these limitations, first, novel materials with desired optoelectronic properties are urgently demanded; second, systematic investigation on contribution and dynamics of triplet excitons in T-OPVs is necessary; third, close multidisciplinary collaboration is required, as proved by the development of S-OPVs.

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Triplet excited state properties in variable gap π-conjugated donor–acceptor–donor chromophores

Abstract: Intersystem crossing in π-conjugated donor–acceptor–donor chromophores is controlled by the strength of the donor–acceptor interaction.

Cited by 64 publications

References 52 publications

Effect of Oligomer Length on Photophysical Properties of Platinum Acetylide Donor–Acceptor–Donor Oligomers

Effect of Oligomer Length on Photophysical Properties of Platinum Acetylide Donor–Acceptor–Donor Oligomers

Precisely Defined Conjugated Oligoelectrolytes for Biosensing and Therapeutics

Limitations and Perspectives on Triplet‐Material‐Based Organic Photovoltaic Devices

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