Photostability of pentacene and 6,13-disubstituted pentacene derivatives: a theoretical and experimental mechanistic study

Northrop, Brian H.; Houk, K. N.; Maliakal, Ashok

doi:10.1039/b813752h

Cited by 41 publications

(61 citation statements)

References 26 publications

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“…Nevertheless, it was found that BT 1 , BT 2 and BT 3 have half‐lives of around 3, 36, and 14 days, respectively, which correspond to an increased stability of 1.8, 21, and 7.6 times that of TIPS–PEN (1.7 days). As expected, there is a clear relationship between the stability and the LUMO energy level of BT materials –. Remarkably, BT 1 is more stable than TIPS–PEN at the beginning of the photo‐oxidation process even though its ionization potential and electron affinity are lower.…”

Section: Resultssupporting

confidence: 67%

Low Bandgap Bistetracene‐Based Organic Semiconductors Exhibiting Air Stability, High Aromaticity and Mobility

Sbargoud

Mamada

Jousselin‐Oba

et al. 2017

Chemistry A European J

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The benchmark of soluble organic semiconductors based on acenes is the 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-PEN). However TIPS-PEN still suffers from photoinduced oxidation due to its low degree of aromaticity. Increasing the aromaticity while keeping similar optical and electrochemical properties as well as a shape suitable for good hole transport can be achieved with two-dimensional polycyclic aromatic hydrocarbons (2D-PAHs). Herein, we present an efficient synthesis and characterization of bistetracene derivatives that exhibit a band gap up to 1.71 eV and an increased stability up to 21 times compared to TIPS-PEN and mobility over 0.1 cm V s in solution-processed organic field-effect transistors. Based on simple structural consideration, the high stability is attributed to the aromaticity of the bistetracene which is comparable to an anthrancene along each tetracene. According to Clar's sextet rule, the bistetracene should be best regarded as two anthracenes fused at the face bridged by two ethylenic spacers. The synthesis path paves the way towards the preparation of ambipolar and/or longer 2D-PAHs such as bispentacenes and could give rise to organic semiconductors with interesting properties.

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Section: Resultssupporting

confidence: 67%

Low Bandgap Bistetracene‐Based Organic Semiconductors Exhibiting Air Stability, High Aromaticity and Mobility

Sbargoud

Mamada

Jousselin‐Oba

et al. 2017

Chemistry A European J

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“…650 nm in hexanes) [58]. Several groups have also tried to vary the electronic nature of the substituents on pentacene to explore various properties [59,60,61,62,63], including the influence on stability [48,64,65]. Even so, the impact of various substitution patterns on stability as well as the mechanism of photodegradation are still not well understood [48,66].…”

Section: Pentacene-based Polycyclic Aromatic Hydrocarbon Conjugatementioning

confidence: 99%

Oligomers and Polymers Based on Pentacene Building Blocks

Lehnherr

Tykwinski

2010

Materials

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Functionalized pentacene derivatives continue to provide unique materials for organic semiconductor applications. Although oligomers and polymers based on pentacene building blocks remain quite rare, recent synthetic achievements have provided a number of examples with varied structural motifs. This review highlights recent work in this area and, when possible, contrasts the properties of defined-length pentacene oligomers to those of mono- and polymeric systems.

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“…Electron transfer rates from excited-state pentacenes are also observed to be fast and solvent-dependent. [ 3 ] Deactivation of the initial singlet state by mechanisms which can compete with O 2 activation therefore serves to increase photostability. The main non-radiative mechanism for this is singlet fi ssion [ 10,11 ] via interaction with a second TIPS-pentacene molecule to produce a pair of triplets.…”

Section: Concentration-and Solvent-dependent Photochemical Instabilitmentioning

confidence: 99%

“…Pentacene for example has a very short half-life in solution under the infl uence of light; this behaviour can be attenuated markedly by derivatisation at the 6-and 13-positions. [1][2][3] As a consequence, materials such as 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) are becoming popular replacements for pentacene in electronic devices. [ 4,5 ] However, these derivatives are themselves still prone to photochemical degradation during processing, which potentially perturbs both the optical absorption and electronic properties of fi lms cast from solution.…”

mentioning

confidence: 99%

“…[ 15 ] Direct observation of the kinetics of singlet fi ssion of TIPSpentacene in anhydrous, O 2 -free CHCl 3 solution over a range of concentrations reveals a singlet lifetime of ∼13 ns, [ 18 ] whilst a high-concentration triplet yield of 200% and triplet formation at a rate approaching the diffusion limit indicates the effi ciency of the process. Physical quenching must also be considered as a deactivation route in any condensed medium.…”

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confidence: 99%

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Concentration‐ and Solvent‐Dependent Photochemical Instability of 6,13‐Bis(triisopropysilylethynyl)pentacene

Abu-Sen

Morrison

Horn

et al. 2014

Advanced Optical Materials

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lifetimes are also strongly environment-dependent, ranging from around 7 ns in dilute solution [ 17 ] to sub-ps in thin fi lms. [ 15 ] Direct observation of the kinetics of singlet fi ssion of TIPSpentacene in anhydrous, O 2 -free CHCl 3 solution over a range of concentrations reveals a singlet lifetime of ∼13 ns, [ 18 ] whilst a high-concentration triplet yield of 200% and triplet formation at a rate approaching the diffusion limit indicates the effi ciency of the process. Physical quenching must also be considered as a deactivation route in any condensed medium. Stability in solution is therefore controlled by the rates and quantum yields of these processes, many of which are not known. Recent reports of half-life increase by the attachment of stable radical species to pentacenes is further evidence of the importance of the initial singlet state lifetime. [ 19 ] In this communication, a systematic study of the half-life of TIPS-pentacene in a variety of air-equilibrated common solvents (including toluene, tetrahydrofuran (THF), dichloromethane, chloroform, isopropanol (IPA), decane and dodecane) by UVvisible spectroscopy at concentrations ranging from 2.5 × 10 −6 M to 2 × 10 −2 M is reported. Correlation of the variation of halflife for TIPS-pentacene photoxidation with TIPS-pentacene concentration, solubility parameters, dissolved O 2 concentrations and intermolecular distances yields important new insight into the processes involved. In particular, a non-linear concentration dependence is observed which points to a further perturbation in solution due to the onset of aggregation.UV-visible spectra for TIPS-pentacene in toluene over a range of concentrations from 270-800 nm in a 10 mm pathlength cuvette are characterized by three long-wavelength bands at 643, 592, and 549 nm ( Figure 1 a). These spectral features correspond to the known HOMO-LUMO gap with its associated vibrational structure. [ 20,21 ] The λ max values of the longest wavelength absorption do not appear to vary with concentration over the range shown but are observed to vary slightly with solvent (Supporting Information, S4.1). Upon photodegradation, these longer wavelength bands decrease with exposure whilst new features grow in below 450 nm. Mass spectra and NMR spectra confi rm that the main product is the 6,13-endoperoxide of TIPS-pentacene (Supporting Information, S1); this shows no features in the visible absorption spectra because the conjugated π-system in the product is too short (comprising 2 naphthalene rings). The new features observed below 450 nm are due to small quantities of the 5,14-endoperoxide (effectively a substituted anthracene. [ 6 ] For each sample, plots of normalized A/A 0 at 643 nm versus time were made as shown in Figure 1 b. These absorbance-time profi les were found to be reproducible to +/-5%, with all formulations showing retardation in rate beyond t 1/2 . Comparable decays were also measured in THF, dichloromethane, IPA, chloroform, dodecane and decane over the same concentration range (Supporting Information, ...

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Photostability of pentacene and 6,13-disubstituted pentacene derivatives: a theoretical and experimental mechanistic study

Cited by 41 publications

References 26 publications

Low Bandgap Bistetracene‐Based Organic Semiconductors Exhibiting Air Stability, High Aromaticity and Mobility

Low Bandgap Bistetracene‐Based Organic Semiconductors Exhibiting Air Stability, High Aromaticity and Mobility

Oligomers and Polymers Based on Pentacene Building Blocks

Concentration‐ and Solvent‐Dependent Photochemical Instability of 6,13‐Bis(triisopropysilylethynyl)pentacene

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