Showing papers on "Fluorene published in 2015"
TL;DR: A new fluorene-based AIE-active gold(i) complex was designed and synthesized that exhibits a crystallization-induced emission enhancement (CIEE) effect and reversible mechanochromic behavior with fluorescence changes between green and yellow emissions.
176 citations
TL;DR: In this article, three novel fluorene-based polymers with pendant alkyltrimethylammonium groups were synthesized and characterized, and the polymeric membranes were transparent and flexible and exhibited hydroxide ion conductivities above 100 mS/cm at 80 °C.
Abstract: Three novel fluorene-based polymers with pendant alkyltrimethylammonium groups were synthesized and characterized. The polymers were soluble in dimethylformamide, and dimethyl sulfoxide at room temperature and methanol at 40 °C while remaining insoluble in water. The polymeric membranes were transparent and flexible and exhibited hydroxide ion conductivities above 100 mS/cm at 80 °C. The results of 1H NMR and titration measurements demonstrated an excellent chemical stability of the synthesized polyfluorene, even after treatment in 1 M NaOH solution at 80 °C for 30 days. The results of this study suggest a feasible approach to the synthesis and practical applications of a new class of alkaline anion exchange membranes.
159 citations
TL;DR: The results showed that PS generated the most total PAH, followed by PVC, PET, and lignin, while benzo[a]anthracene and chrysene were notable in the tar of PS, PVC, and PET.
126 citations
TL;DR: The electrochemical impedance spectroscopy investigations provide further support for the variations in the electron injection and transfer kinetics due to the structural modifications of fluorene-based organic dyes.
Abstract: Two types of fluorene-based organic dyes featuring T-shape/rod-shape molecular configuration with phenothiazine donor and cyanoacrylic acid acceptor have been synthesized and characterized as sensitizers for dye-sensitized solar cells. Phenothiazine is functionalized at either nitrogen (N10) or carbon (C3) to obtain T-shape and rod-like organic dyes, respectively. The effect of structural alternation on the optical, electrochemical, and the photovoltaic properties is investigated. The crystal structure determination of the dye containing phenyl linker revealed cofacial slip-stack columnar packing of the molecules. The trends in the optical properties of the dyes are interpreted using time-dependent density functional theory (TDDFT) computations. The rod-shaped dyes exhibited longer wavelength absorption and low oxidation potentials when compared to the corresponding T-shaped dyes attributable to the favorable electronic overlap between the phenothiazine unit and the rest of the molecule in the former dyes...
79 citations
TL;DR: A transition-metal-free intramolecular aromatic substitution/Büchner reaction is presented that uses readily available N-tosylhydrazones as the diazo compound precursors and show wide substrate scope.
Abstract: Intramolecular aromatic substitution and Buchner reaction have been established as powerful methods for the construction of polycyclic compounds. These reactions are traditionally catalyzed by Rh(II) catalysts with α-diazocarbonyl compounds as the substrates. Herein a transition-metal-free intramolecular aromatic substitution/Buchner reaction is presented. These reactions use readily available N-tosylhydrazones as the diazo compound precursors and show wide substrate scope.
77 citations
TL;DR: In this paper, three star-shaped derivatives of 1,3,5-triphenylbenzene bonded to fluorene moieties with various linking groups were designed and synthesized.
54 citations
TL;DR: A second generation of dihydroindeno[1,2-a]fluorene is obtained with strongly enhanced performance in green and sky-blue phosphorescent organic light-emitting diodes (PhOLEDs) relative to the first generation of materials.
Abstract: New families of donor/acceptor semiconductors based on dihydroindeno[1,2-a]fluorene and dihydroindeno[2,1-b]fluorene are reported. Due to the spiro bridges, this new generation of dihydroindenofluorenes allows a spatial separation of HOMO and LUMO, which retains the high ET value of the dihydroindenofluorene backbone and excellent physical properties. This control of the electronic and physical properties has allowed a second generation of dihydroindeno[1,2-a]fluorene to be obtained with strongly enhanced performance in green and sky-blue phosphorescent organic light-emitting diodes (PhOLEDs) relative to the first generation of materials. To date, this is the highest performance ever reported for a blue PhOLED by using a dihydroindenofluorene derivative. Through this structure-property relationship study, a remarkable difference of performance between syn and anti isomers has also been highlighted. This surprising behaviour has been attributed to the different symmetry of the two molecules, and highlights the importance of the geometry profiles in the design of host materials for PhOLEDs.
50 citations
TL;DR: In this paper, a nanoporous carbon derived from an aluminum-based metal-organic framework was deposited on stainless steel wires in a sol-gel matrix, and the resulting fibers were applied to the solid-phase microextraction of the polycyclic aromatic hydrocarbons (PAHs) naphthalene, acenaphthene, fluorene, phenanthrene and anthracene from water and soil samples.
Abstract: A nanoporous carbon derived from an aluminum-based metal-organic framework was deposited on stainless steel wires in a sol–gel matrix. The resulting fibers were applied to the solid-phase microextraction of the polycyclic aromatic hydrocarbons (PAHs) naphthalene, acenaphthene, fluorene, phenanthrene and anthracene from water and soil samples. The fiber was then directly inserted into the GC injector and the PAHs were quantified by GC-MS. The effects of salt addition, extraction temperature, extraction time, sample volume and desorption conditions on the extraction efficiency were optimized. A linear response to the analytes was observed in the 0.1 to 12 μg∙L−1 range for water samples, and in the 0.6 to 30 μg∙kg−1 for soil samples, with the correlation coefficients ranging from 0.9934 to 0.9985. The limits of detection ranged from 5.0 to 20 ng∙L−1 for water samples, and from 30 to 90 ng∙kg−1 for soil samples. The recoveries of spiked samples were between 72.4 and 108.0 %, and the precision, expressed as the relative standard deviations, is <12.8 %.
48 citations
TL;DR: In this article, a di-anchoring organic dye based on phenothiazine featuring A-D-πD-A configuration with fluorene as the π linker was designed and successfully synthesized.
47 citations
TL;DR: Modified gas chromatography electron-impact/triple-quadrupole mass spectrometry (GC-EI/MS/MS) utilizing a newly developed hydrogen-injected self-cleaning ion source and modified 9mm extractor lens achieves quantitative separation of 62 polycyclic aromatic hydrocarbons (PAHs).
45 citations
TL;DR: A series of novel polyamides with fluorene-based triphenylamine units in the backbone were prepared from a newly synthesized diamine monomer, N,N-di (4-aminophenyl)-2-amino-9,9-dimethylfluorene, and various dicarboxylic acids via phosphorylation polyamidation technique as mentioned in this paper.
Abstract: A series of novel polyamides with fluorene-based triphenylamine units in the backbone were prepared from a newly synthesized diamine monomer, N,N-di (4-aminophenyl)-2-amino-9,9-dimethylfluorene, and various dicarboxylic acids via phosphorylation polyamidation technique. These polyamides were amorphous and exhibited excellent solubility in many polar solvents and could be solution-cast into flexible polymer films. They possess good thermal stability with glass transition temperature in the range of 256–316 °C and 10% weight loss in excess of 500 °C in nitrogen. The dilute N-methyl-2-pyrrolidone (NMP) solutions of these polyamides showed strong UV-vis absorption bands at 334–367 nm and the polyamide derived from 1,4-cyclohexanedicarboxylic acid exhibited fluorescence maximum at 441 nm with quantum yields up to 47.1%. Furthermore, the fluorescence can be effectively switched between “on” and “off” states by applying reduction and oxidation potentials, exhibiting a high contrast ratio (If/If0) of 12.7. The polymer films showed reversible electrochemical oxidation and reduction, enabling an improved stability of electrochromic characteristics with color changing from colorless to green. The anodically electrochromic films had high coloration efficiency (up to 283 cm2 C−1 at 860 nm) and after over 500 cycles the polymer films still exhibited continuous cyclic stability of electrochromism.
TL;DR: A highly fluorescent an ionic fluorene derivative 1 was synthesized and its photophysical, electrochemical and electroluminescence characteristics were investigated in this paper, where the synthesized compound shows high fluorescence quantum yield around 77% indicates that compound 1 can perform its role as efficient ionic emitter in LEC devices.
TL;DR: The main processes controlling soil polycyclic aromatic hydrocarbon interaction is sorption-desorption as influenced by the soil physicochemical conditions as mentioned in this paper, which can influence translocation, persistence and bioavailability.
TL;DR: A series of luminogens containing formamide or fluorenone units, based on fluorene, have been synthesized and characterized by NMR spectroscopy, mass spectrometry and elemental analysis.
TL;DR: In this paper, the copolymerization of thiophene and fluorene starting from a mixture of the two monomers is investigated, and the Pd(RuPhos) protocol is used.
Abstract: The copolymerization of thiophene and fluorene starting from a mixture of the two monomers is investigated. It is shown that these monomers are incapable of copolymerizing using a Kumada catalyst transfer polycondensation. However, when the Pd(RuPhos) protocol is used, this copolymerization is enabled and gradient copolymers are obtained. Consequently, this protocol is applied to the synthesis of a series of six polymers with varying monomer feeds, and the properties of these gradient copolymers are investigated. This new class of materials, which was previously inaccessible using other catalysts, shows unique properties compared with the block copolymer analogues.
TL;DR: An application of a statistical Suzuki-Miyaura polycondensation reaction for synthesis of a family of carbazole-fluorene-TTBTBTT terpolymers with tailored physical and optoelectronic properties is reported.
TL;DR: In this paper, a novel electron acceptor, namely 2,2′-(12H,12′H-10,10′-spirobi[indeno[2,1-b]fluorene]-12, 12′-diylidene)dimalononitrile, exhibiting a three-dimensional molecular structure was synthesized and its thermal, photophysical, electrochemical, crystal, and photovoltaic properties were investigated.
Abstract: A novel electron acceptor, namely 2,2′-(12H,12′H-10,10′-spirobi[indeno[2,1-b]fluorene]-12,12′-diylidene)dimalononitrile (4CN-spiro), exhibiting a three-dimensional molecular structure was synthesized and its thermal, photophysical, electrochemical, crystal, and photovoltaic properties were investigated. The novel acceptor exhibits excellent thermal stability with a decomposition temperature of 460 °C, an absorption extending to 600 nm, and a LUMO level of −3.63 eV. Solution processed bulk-heterojunction (BHJ) organic solar cells were fabricated using 4CN-spiro as an acceptor and polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) as a donor polymer. The effect of the donor-to-acceptor ratio and processing conditions on the device performance was investigated. A device processed from tetrachloroethane with a donor to acceptor weight ratio of 1 : 1 yielded a power conversion efficiency (PCE) of 0.80%.
TL;DR: In this article, a series of new organic dyes containing fluoreneamine-based donor and carbazole π-spacer are reported, which displayed longer wavelength charge transfer absorption when compared to that of the corresponding phenylamine analogs.
TL;DR: In this article, a series of linear, high-molecular-weight polymers and copolymers were synthesized by one-pot, metal-free superacid-catalyzed polymerization of aliphatic 1,2-diketones.
Abstract: A novel series of linear, high-molecular-weight polymers and copolymers were synthesized by one-pot, metal-free superacid-catalyzed polymerization of aliphatic 1,2-diketones (2,3-butanedione (1a), 2,3-hexadione (1b), 3,4-hexadione (1c), 2,3-butanedione monoxime (1d), pyruvic acid (1e), 1,4-dibromo-2,3-butanedione (1f), 2-bromopyruvic acid (1g), and methyl-3,3,3-trifluoropyruvate (1h) with linear, nonactivated, multiring aromatic hydrocarbons terphenyl (A), biphenyl (B), fluorene (C), and N-ethyl carbazole (D). Depending on the reaction system, the polymerizations were carried out as stoichiometric or non stoichiometric, with direct or inverse monomer addition. Copolymers were obtained by polymerization of 1,2-diketones with a mixture of aromatic hydrocarbons. In the course of the polymerization only one carbonyl group of a 1,2-diketone reacts to form C–C bonds with aromatic fragments while the other functional groups (including the second carbonyl group) are incorporated unchanged into polymer chain. The ...
TL;DR: In this work the first phenazine derivatives with guanidino substituents were prepared and their structural and electronic properties studied in detail, and the influence of coordination on the electronic properties and especially the fluorescence of the phenazine system was analysed.
Abstract: In this work the first phenazine derivatives with guanidino substituents were prepared and their structural and electronic properties studied in detail. The guanidino groups decrease the HOMO–LUMO gap, massively increase the quantum yield for fluorescence and offer sites for metal coordination. The yellow-orange colored 2,3,7,8-tetraguanidino-substituted phenazine shows intense fluorescence. The wavelength of the fluorescence signal is strongly solvent dependent, covering a region from 515 nm in Et2O solution (with a record quantum yield of 0.39 in Et2O) to 640 nm in water. 2,3-Bisguanidino-substituted phenazine is less fluorescent (maximum quantum yield of 0.17 in THF), but exhibits extremely large Stokes shifts. In contrast, guanidino-functionalized fluorenes emit only very weakly. Subsequently, the influence of coordination on the electronic properties and especially the fluorescence of the phenazine system was analysed. Coordination first takes place at the guanidino groups, and leads to a blue shift of the luminescence signal as well as a massive decrease of the luminescence lifetime. Luminescence is almost quenched completely upon CuI coordination. On the other hand, in the case of ZnII coordination the fluorescence signal remains strong (quantum yield of 0.36 in CH3CN). In the case of strong zinc Lewis acids, an excess of metal compound leads to additional coordination at the phenazine N atoms. This is accompanied by significant red-shifts of the lowest-energy transition in the absorption and fluorescence spectra. Pentanuclear complexes with two phenazine units were isolated and structurally characterized, and further aggregation leads to chain polymers.
TL;DR: In this paper, aryl or alkyl substitution on the 9 position of a silafluorene unit is also crucial to the organic light-emitting diode (OLED) performances.
Abstract: Diphenylamino- or cabazolyl-endcapped silafluorene derivatives which show a wide energy band gap, a high fluorescence quantum yield and high stability have been designed, synthesized, and characterized. Double layer electroluminescent devices of these silafluorene derivatives exhibited efficient blue emission. The non-doped double layer OLEDs containing TDMS, TDPS, CDMS, or CDPS exhibited better electroluminescence efficiencies than those of the devices using the reference emitter DPFL-NPB, among which the best device was with TDPS, which showed a maximum current efficiency of 1.62 cd A−1 and an external quantum efficiency (EQE) of 1.36%. The solution processed device using TDPS as dopant exhibited a high performance with an EQE of 2.48% and an obviously low turn-on voltage of 4 V, when compared to the results of the reference device. The replacement of the carbon atom of the fluorene unit with a silicon atom could lower the energy gap effectively and improve the thermal stability as well as optical performances. The results indicate that the end-capped arylamino groups affect the organic light-emitting diode (OLED) performances greatly and aryl or alkyl substitution on the 9-position of a silafluorene unit is also crucial to the OLED performances of this kind of silafluorene.
TL;DR: In this article, solid state emissive compounds with very high quantum efficiencies (ΦF up to 68%) were achieved by chemical alteration of the excited state intramolecular proton transfer (ESIPT) 2-2′-hydroxy benzothiazole (HBT) unit.
Abstract: Tuning or switching of the solid state luminescence of organic materials is an attractive target for both basic research and practical applications. In the present study, solid state emissive compounds with very high quantum efficiencies (ΦF up to 68%) were achieved by chemical alteration of the excited state intramolecular proton transfer (ESIPT) 2-2′-hydroxy benzothiazole (HBT) unit. Five ESIPT inspired compounds based on fluorene were synthesized via Suzuki coupling reaction. Their photophysical properties were studied by means of steady state absorption, emission spectra and a time resolved emission method in solid as well as in solution of different polarities. The fluorophores showed absorption in the UV region and emission in the visible region with large Stokes shift (∼232 nm). Efficient yellow emissive compounds showed very high quantum yields (ΦF = 55–68%) in the solid state, which are the highest quantum yields in the solid state to the best of our knowledge, for fluorene based ESIPT molecules. The fluorescence lifetime in the solid state is between 3.48–5.21 ns, while it is 5–10 fold less in chloroform (0.52–0.75 ns) solution. The optical properties of these compounds are sensitive towards the polarity of the medium. The structural properties, such as X-ray single crystal analyses, DSC and TGA were studied, and the lack of stacking and/or hydrogen bonding interactions around HBT motifs reveals enough room for ESIPT in the series of molecules even in their solid state. The DFT computations were performed to support experimental results and the calculations are well in line with the experimental results. These suggest high quantum efficiency ascribed to the large orbital energy difference between HOMOs and LUMOs of enol and keto forms transformed via ESIPT, and hence, singlet energy localization onto the keto form. The intra-molecular charge transfer nature between fluorene and HBT units plays a key role for the localization of energy on HBT motifs in their excited states.
TL;DR: In this paper, a series of diarylmaleimide derivatives and polymers based on amide group were designed and synthesized to detect anions selectively and sensitively, which showed higher selectivity than FAMs with sensing for only fluoride.
TL;DR: In this paper, six small molecules with three different dye units, ECA, 1,3-indandione (IN), and 3-ethylrhodanine (RH), attached to both ends of thiophene-flanked carbazole (Cz) or fluorene (Flu) cores were synthesized and used as acceptors in organic photovoltaic cells.
Abstract: Six small molecules with three different dye units, ethyl cyanoacetate (ECA), 1,3-indandione (IN), and 3-ethylrhodanine (RH), attached to both ends of thiophene-flanked carbazole (Cz) or fluorene (Flu) cores were synthesized and used as acceptors in organic photovoltaic cells (OPVs). Their optical and electrochemical, and consequent photovoltaic parameters varied mainly according to the dye units. The OPV cells were fabricated with the configuration ITO/PEDOT:PSS/poly(3-hexylthiophene):small molecule/LiF/Al and all devices except for Cz-IN showed photovoltaic performances with power conversion efficiencies (PCEs) in the range of 1.03–3.08% and open-circuit voltages as high as 1.03 V. Among them, the ECA and RH series had relatively high open-circuit voltages values because of their high-lying lowest unoccupied molecular orbital energy levels. Devices based on Flu-IN and the RH series showed high short-circuit currents (JSC) because of the strong molecular aggregation, as evidenced by red-shifted UV absorption from solution to film. The adequate molecular aggregation in Flu-IN and RH films enhanced electron transport between the molecules, resulting in devices with high JSC and PCE values. This work demonstrates that the introduction of dye end units onto carbazole- and fluorene-based small molecules provides good candidates for non-fullerene acceptors.
TL;DR: Electrochromic systems based on heat cross-linkable arylamine-substituted fluorene derivatives, FD and FDOMe, are reported and exhibited thermally activated cross-linking above their melting temperatures, which was confirmed through absorption, differential scanning calorimetry (DSC), FT-IR, and wide-angle X-ray diffraction techniques.
Abstract: Multicolor electrochromic systems based on heat cross-linkable arylamine-substituted fluorene derivatives, FD and FDOMe, are reported. These derivatives with pendant vinyl groups have been synthesized by the Buchwald–Hartwig amination reaction and were well-characterized using various analytical and spectroscopic techniques such as NMR, ESI-MS, and single-crystal X-ray diffraction analysis. FD and FDOMe exhibited thermally activated cross-linking above their melting temperatures, which was confirmed through absorption, differential scanning calorimetry (DSC), FT-IR, and wide-angle X-ray diffraction (WAXD) techniques. Cross-linked FD films (FD-X) on ITO showed two reversible redox peaks at 0.74 and 0.91 V (versus Ag/AgCl) that correspond to the formation of radical cations and dications, respectively. The corresponding redox peaks were observed at 0.6 and 0.8 V for cross-linked FDOMe films (FDOMe-X). Spectroelectrochemical studies of the electrochromic films on ITO revealed multicolor electrochromism of FD...
TL;DR: In this article, the effect of fluorine substitution on the ubiquitously-studied, moderate band gap polymer, poly(2,7-fluorene-alt-dithienylbenzothiadiazole) (PFO-DBT) has been investigated by substituting the hydrogen atoms at the 5,6-positions of benzothia to yield the polymer, PFO-DffBT.
Abstract: The effect of fluorine substitution on the ubiquitously-studied, moderate band gap polymer, poly(2,7-fluorene-alt-dithienylbenzothiadiazole) (PFO-DBT) has been investigated by substituting the hydrogen atoms at the 5,6-positions of benzothiadiazole to yield the polymer, PFO-DffBT. An analogous polymer, PFDo-DffBT, with longer chains on the 9H-positions of the fluorene moiety, was synthesised to rectify the low Mw of PFO-DffBT. In thin films, both fluorinated polymers display absorption bands with well-defined shoulders, giving optical band gaps of 1.91 and 1.89 eV, respectively. The optical band gap of PFDo-DBT is identical to that of PFDo-DffBT, despite the former having a significantly larger Mw. However, PFDo-DffBT displayed a blue-shifted λmax relative to its non-fluorinated counterpart. The HOMO levels of PFO-DffBT and PFDo-DffBT are lower than their non-fluorinated analogues, owing to the incorporation of electron withdrawing substituents on the benzothiadiazole moiety. The photovoltaic properties of all polymers were investigated by fabricating bulk heterojunction (BHJ) polymer solar cells using PC70BM as the electron acceptor. PFO-DffBT displayed the highest efficiency with a PCE of 4.4% despite having the lowest Mw of all polymers studied.
TL;DR: In this paper, the distribution of products in the range of gasoline and middle distillate cuts obtained in the catalytic cracking of heavy aromatics and polycyclic aromatic hydrocarbons over a fluidized catalyst was studied.
Abstract: The distribution of products in the range of gasoline and middle distillate cuts obtained in the catalytic cracking of heavy aromatics and polycyclic aromatic hydrocarbons over a fluidized catalytic cracking (FCC) catalyst was studied. 1-Phenyloctane, biphenyl, fluorene, 9,10-dihydrophenanthrene, naphthalene, phenanthrene, pyrene, and benz[a]anthracene were used as model compounds of alkylaromatic, naphthenic-aromatic, and polyaromatic hydrocarbons, which are present in vacuum gas oil and residual feedstocks in the FCC process. The catalyst was used in its fresh and equilibrium forms at 450 °C in a Chemical Reactor Engineering Centre Riser Simulator reactor with reaction times from 2 to 6 s. Thermal cracking reactions overwhelm the catalytic conversion of naphthenic-aromatic compounds, such as fluorene and 9,10-dihydrophenanthrene. Under the same conditions, the fresh catalyst was more active than the equilibrium catalyst. The alkylaromatic, naphthenic-aromatic, and polyaromatic hydrocarbons, showed catal...
TL;DR: In this article, a copolymer based on fluorene and perylene diimide with pendent amino groups, namely poly[2,9-bis(3-(dimethylamino)propyl)-5-methyl-12-(7methyl-9, 9-dioctyl-9H-fluoren-2-yl)anthra(2,1,9def:6,5,10-d'e'f')diisoquinoline-1,3,8,10(2H,9H)-tetraone
Abstract: A novel copolymer based on fluorene and perylene diimide with pendent amino groups, namely poly[2,9-bis(3-(dimethylamino)propyl)-5-methyl-12-(7-methyl-9,9-dioctyl-9H-fluoren-2-yl)anthra(2,1,9-def:6,5,10-d'e'f')diisoquinoline-1,3,8,10(2H,9H)-tetraone] (PF-PDIN), has been synthesized and developed as a cathode interlayer for inverted polymer solar cells (I-PSCs). PF-PDIN shows good alcohol solubility and uniform film morphology. The device with the configuration of ITO/PF-PDIN/P3HT:PC61BM/MoO3/Ag exhibits a power conversion efficiency (PCE) of 3.54%. The resulting device shows higher efficiency and better stability relative to the device using an organic small-molecule analogue, 2,9-bis(3-(dimethylamino)propyl)anthrax(2,1,9-def:6,5,10-d'e'f')diisoquinoline-1,3,8,10(2H,9H)-tetraone (PDIN), as the cathode interlayer. This work indicates that PF-PDIN is a new promising candidate cathode interlayer for highly efficient and stable PSCs.
TL;DR: In this paper, a comprehensive spectroscopic (singlet-singlet and transient) and photophysical investigation (fluorescence, phosphorescence and triplet lifetimes together with fluorescence, triplet occupation and singlet oxygen sensitization quantum yields) of the copolymers was carried out.
Abstract: Alternating indigo–fluorene copolymers have been synthesized by the coupling of didromoindigo and fluorendiboronic ester monomers. The low solubility of the copolymers only allowed for the synthesis of moderate molecular weight copolymers, with a degree of polymerization (DP) up to 11. The syntheses were accomplished through a 10% excess of the fluorene-based monomer component in an AA/BB-type polycondensation mixture. Next, a comprehensive spectroscopic (singlet–singlet and transient – from fs to μs – absorption, fluorescence and phosphorescence spectra) and photophysical investigation (fluorescence, phosphorescence and triplet lifetimes together with fluorescence and triplet occupation and singlet oxygen sensitization quantum yields) of the copolymers was carried out. The experiments were complemented with the spectroscopic results from a fluorene–indigo–fluorene model compound, as well as by TDDFT calculations. Based on our kinetics analysis, singlet energy transfer from the fluorene to indigo moieties is found to be inefficient. Besides the low energy indigo-related absorption band, an additional intermediate energy absorption band is also observed between 400 nm and 500 nm, both for the copolymer and for the model compound. Excitation into this band causes an emission of the indigo moiety. The triplet state is found to be mainly localized at the fluorene moiety; however, the decrease of the phosphorescence quantum yield (ϕPh) when going from the monomeric 9,9-bis(dodecyl)fluorene (0.075) to the model trimer (0.003) and copolymer (ϕPh = 0.008) suggests that excitation energy transfer occurs in the triplet state. This is further confirmed by the higher level of delocalization of the transient triplet–triplet absorption spectra of the copolymer relative to the monomeric 9,9-bis(dodecyl)fluorene.