Communication of Bichromophore Emission upon Aggregation – Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines

Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution pattern-tunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors.     

Studies of the Energy Transfer among Allophycocyanin from Phycobilisomes of Polysiphonia urceolata by Time-Resolved Fluorescence Isotropic and Anisotropic Spectroscopy

Abstract— The excitation energy transfer processes in the allophycocyanin (APC) monomer and trimer from phycobilisomes of Polysiphonia urceolata were studied using picosecond time-resolved fluorescence isotropic and anisotropic spectroscopy. Based on our experimental results, conclusions could be drawn as follows: (1) After the processes of exciton localization are finished, the localized excitation energy on any chromophore can be transferred to the other chromophores due to the weak couplings between them, and the processes among three p₈₄-phycocyaninbilin (PCB) chromophores in the center of the ring shape of the APC trimer are more important than those of between a₈₄- and p₈₄-PCB chromophores in the same monomer. (2) The decay time constants of 95 ± 5 ps and 40 ± 5 ps components, observed by us in this work, were assigned to the excitation energy transfer or redistribution between α₈₄- and β₈₄-PCB chromophores in the same monomer of the APC trimer and among three β₈₄-PCB chromophores in the center of the ring shape of the APC trimer, respectively. Specifically, the assignment of the decay constants for the 40 ± 5 ps component was different from those of previous results. (3) Based on the model of Debreczeny, and using the fluorescence residual anisotropy r(∞) with a probing wavelength of 650 nm, the angles between the C₃ symmetry axis and transition dipoles of α₈₄- and -PCB chromophores were found to be φ_a84= 67° and φ_β84= 148°, respectively, which are in agreement with the prediction of the X-ray crystal structure of APC. (4) The results show that anisotropy decays, observed with the APC trimer, did exhibit a strongly probing wavelength dependence that did not show up in the monomer.     

Synthesis and photogeneration properties of copolyacrylate having carbazole donor and trinitrofluorenone acceptor chromophores

Novel copolymers containing both donor and acceptor chromophores have been synthesized by free radical polymerization of 2-N-carbazolylethyl acrylate and 2′-acrylylethyl-4,5,7-trinitrofluorenone-2-carboxylate. The charge transfer complexation occurs in copolymers in a similar way to poly(2-N-carbazolylethyl acrylate) molecularly doped with 2,4,7-trinitrofluorenone (TNF) and a model compound, ethyl 4,5,7-trinitrofluorene-2-carboxylate (Et-TNF). Copolymer and doped systems exhibit obvious CT bands in a 440–600 nm region, where the former shows higher absorption than the latter. Glass-transition temperatures show positive deviations from the weight-average values of copolymers, indicating the partial interchain interaction of copolymers in solid state. Quantum efficiency of hole photogeneration of the copolymer with the 0.05 to 1.0 molar ratio of TNF to carbazole chromophores is higher than those of the corresponding molecularly TNF- and Et-TNF-doped poly(2-N-carbazolylethyl acrylate), especially at lower electric fields.     

Photophysics of 9,9-Dimethylacridan-Substituted Phenylstyrylpyrimidines Exhibiting Long-Lived Intramolecular Charge-Transfer Fluorescence and Aggregation-Induced Emission Characteristics

Six pyrimidine-based push–pull systems substituted at positions C2 and C4/6 with phenylacridan and styryl moieties, employing methoxy or N,N-diphenylamino donors, have been designed and synthesized through cross-coupling and Knoevenagel reactions. X-ray analysis confirmed that the molecular structure featured the acridan moiety arranged perpendicularly to the residual π system. Photophysical studies revealed significant differences between the methoxy and N,N-diphenylamino chromophores. Solvatochromic studies revealed that the methoxy derivatives showed dual emission in polar solvents. Time-resolved spectroscopy revealed that the higher energy band involved very fast (<80 ps) fluorescence, whereas the lower energy one included long components (≈30 ns) due to long-lived intramolecular charge-transfer fluorescence. In contrast to N,N-diphenylamino chromophores, the methoxy derivatives also showed aggregation-induced emission in mixtures of THF/water, as well as dual emission in thin films, covering almost the whole visible spectrum with corresponding chromaticity coordinates not far from that of pure white light. These properties render the methoxy derivatives as very promising organic materials for white organic light-emitting diodes.     

Photochemistry of polymeric systems. II. Photocrosslinking of polymers and copolymers containing various aromatic N-oxide groups

2-Methyl-5-vinylpyridine-N-oxide, 4-vinylquinoline-N-oxide. 9-vinylacridine-N-oxide, p-N,N-dimethylaminostyrene-N-oxide units were introduced in polymeric chains as homopolymers or/and as styrene copolymers to study their photocrosslinking. The method used for characterization of photocrosslinked films was a “photoresist test” described in Part I of this series. The photosensitivity of the different chromophores bound to the different polymer has also been studied by UV, IR, and fluorescence spectrophotometries. The use of aromatic amine N-oxide groups in polymers seems to be a general means to produce their photocrosslinking by radical reactions. Among the different polymeric materials prepared, 4-vinylpyridine-N-oxide and 4-vinylquinoline-N-oxide are the most photosensitive.     

基于聚集荧光增强体系的掺杂纳米粒子的可调控荧光发射与能量传递性质研究

通过再沉淀法制备了平均粒径200 nm左右的N,N'-双[4-(2'-苯并噻唑)-3-羟苯基]-5-叔丁基异酞酰胺(DHBIA)有机纳米粒子. 纳米粒子呈现出明显的聚集诱导荧光增强(AIEE)性质. 基于DHBIA聚集体的强荧光发射强度, 当其中掺杂有红光发射化合物N,N'-双[(4-二苯胺)-苯甲醛缩]二氨基马来腈(PBDM)作为能量受体时, 可清楚地观察到掺杂纳米颗粒中两种组分间的能量传递现象. 结果表明: 通过改变分子PBDM在体系中的掺杂浓度, 可实现对体系发光由绿色到红色的调控.     

Enhanced photovoltaic performance of quasi-solid-state dye-sensitized solar cells via incorporating quaternized ammonium iodide-containing conjugated polymer into PEO gel electrolytes

In this study, a series of gel electrolytes prepared from blends of alternating conjugated polymer electrolytes (CPEs)/poly(ethylene oxide) (PEO) were developed for use in quasi-solid-state dye-sensitized solar cells (DSSCs). The alternating CPEs poly[(N-(3′-((N,N-dimethyl)-N-ethylammonium)propyl)-3,6-carbazole)-alt-(9,9-dioctyl-2,7-fluorene)]diiodide, poly[(N-(3′-((N,N-dimethyl)-N-ethylammonium)propyl)-3,6-carbazole)-alt-(9,9-bis(2-(2-methoxyethoxy)ethyl)-2,7-fluorene)]diiodide (MPCFO-E), and poly[(N-(3′-((N,N-dimethyl)-N-ethylammonium)propyl)-3,6-carbazole)-alt-(siloxane substituted-2,7-fluorene)]diiodide (MPCFS-E) were synthesized through copolymerization of carbazole units (featuring quaternized ammonium iodide groups) and fluorene units featuring flexible side chains (9,9-dioctylfluorene, ethylene oxide-substituted fluorene, and siloxane-substituted fluorene, respectively). The MPCFO-E/PEO-based and MPCFS-E/PEO-based DSSCs exhibited lower electrochemical resistances, superior photovoltaic (PV) properties, and improved PV stabilities relative to those of the corresponding PEO-based DSSC. Among the studied systems, the DSSC based on the MPCFO-E (0.5 wt.%)/PEO blend electrolyte exhibited the best PV performance, with a short current density of 4.97 mA cm⁻² and a photoenergy conversion efficiency of 1.17%.     

Lifetime Shortening and Fast Energy‐Tansfer Processes upon Dimerization of a A‐π‐D‐π‐A Molecule

Time‐resolved fluorescence and transient absorption experiments uncover a distinct change in the relaxation dynamics of the homo‐dimer formed by two 2,5‐bis[1‐(4‐N‐methylpyridinium)ethen‐2‐yl)]‐N‐methylpyrrole ditriflate ( M ) units linked by a short alkyl chain when compared to that of the monomer M . Fluorescence decay traces reveal characteristic decay times of 1.1 ns and 210 ps for M and the dimer, respectively. Transient absorption spectra in the spectral range of 425–1050 nm display similar spectral features for both systems, but strongly differ in the characteristic relaxation times gathered from a global fit of the experimental data. To rationalize the data we propose that after excitation of the dimer the energy localizes on one M branch and then decays to a dark state, peculiar only of the dimer. This dark state relaxes to the ground state within 210 ps through non‐radiative relaxation. The nature of the dark state is discussed in relation to different possible photophysical processes such as excimer formation and charge transfer between the two M units. Anisotropy decay traces of the probe‐beam differential transmittance of M and the dimer fall on complete different time scales as well. The anisotropy decay for M is satisfactorily ascribed to rotational diffusion in DMSO, whereas for the dimer it occurs on a faster time scale and is likely caused by energy‐transfer processes between the two monomer M units.     

Energy and electron transfer in enhanced two-photon-absorbing systems with triplet cores

Enhanced two-photon-absorbing (2PA) systems with triplet cores are currently under scrutiny for several biomedical applications, including photodynamic therapy (PDT) and two-photon microscopy of oxygen. The performance of so far developed molecules, however, is substantially below expected. In this study we take a detailed look at the processes occurring in these systems and propose ways to improve their performance. We focus on the interchromophore distance tuning as a means for optimization of two-photon sensors for oxygen. In these constructs, energy transfer from several 2PA chromophores is used to enhance the effective 2PA cross section of phosphorescent metalloporphyrins. Previous studies have indicated that intramolecular electron transfer (ET) can act as an effective quencher of phosphorescence, decreasing the overall sensor efficiency. We studied the interplay between 2PA, energy transfer, electron transfer, and phosphorescence emission using Rhodamine B-Pt tetrabenzoporphyrin (RhB-PtTBP) adducts as model compounds. 2PA cross sections (sigma2) of tetrabenzoporphyrins (TBPs) are in the range of several tens of GM units (near 800 nm), making TBPs superior 2PA chromophores compared to regular porphyrins (sigma2 values typically 1-2 GM). Relatively large 2PA cross sections of rhodamines (about 200 GM in 800-850 nm range) and their high photostabilities make them good candidates as 2PA antennae. Fluorescence of Rhodamine B (lambda(fl) = 590 nm, phi(fl) = 0.5 in EtOH) overlaps with the Q-band of phosphorescent PtTBP (lambda(abs) = 615 nm, epsilon = 98 000 M(-1) cm(-1), phi(p) approximately 0.1), suggesting that a significant amplification of the 2PA-induced phosphorescence via fluorescence resonance energy transfer (FRET) might occur. However, most of the excitation energy in RhB-PtTBP assemblies is consumed in several intramolecular ET processes. By installing rigid nonconducting decaproline spacers (Pro10) between RhB and PtTBP, the intramolecular ETs were suppressed, while the chromophores were kept within the F?rster r0 distance in order to maintain high FRET efficiency. The resulting assemblies exhibit linear amplification of their 2PA-induced phosphorescence upon increase in the number of 2PA antenna chromophores and show high oxygen sensitivity. We also have found that PtTBPs possess unexpectedly strong forbidden S0 --> T1 bands (lambda(max) = 762 nm, epsilon = 120 M-1 cm-1). The latter may overlap with the laser spectrum and lead to unwanted linear excitation.     

Synthesis,Crystal structure and Fluorescence properties of a Binuclear Terbium(Iii) complex of N-(2-Pyridinyl)Ketoacetamide

A binuclear terbium(III) complex of N-(2-pyridinyl)ketoacetamide (HL) was synthesized and its crystal structure determined. Each terbium(III) binds to one N,O-bidentate HL, one O,O-bidentate L and two N,μ-O,O-tridentate bridging L ligands; the coordination polyhedron is a distorted square antiprism. The pyridine N and keto O atoms of the binucleating ligand are coordinated to each Tb with the amide O acting as a bridging atom. The adjacent [Tb₂(HL)₂L₄]²⁺ units are bridged by double C(R)NH…ONO₂…HN(R)C hydrogen bonds to form an infinite 1-D chain, and a 2-D layer structure results from a rare near face-to-face π,π-stacking interaction between the pyridine rings of the adjacent chains. The crystal structure analysis reveals that the ligands completely shield the Ln(III) ions. Excited by the absorption band at 370?nm, the Tb(III) complex displays characteristic metal-centered fluorescence while the ligand fluorescence is completely quenched, showing that efficient ligand-to-metal energy transfer (antenna effect) occurs.     

Fluorescent investigation of the interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin: synchronous fluorescence determination of serum albumin

The interactions between N-(p-chlorophenyl)-N′-(1-naphthyl) thiourea and serum albumin were investigated by fluorescence spectroscopy and UV absorption spectrum under physiological conditions. The results of spectroscopic measurements suggested that N-(p-chlorophenyl)-N′-(1-naphthyl) thiourea should have a strong ability to quench the intrinsic fluorescence of both bovine serum albumin and human serum albumin through static quenching procedure, and the hydrophobic interaction was the predominant intermolecular force stabilizing the complex. Thermodynamic parameter enthalpy changes (ΔH) and entropy changes (ΔS) were calculated according to the Vant’Hoff equation. The binding distances between N-(p-chlorophenyl)-N′-(1-naphthyl) thiourea and the proteins were evaluated on the basis of the theory of Föster energy transfer. In addition, the effects of other ions on the binding constants of complexes were also discussed. Synchronous fluorescence technology was successfully applied to the determination of serum albumins added to the CPNT solution.     

Benzophenone and zinc(II) phthalocyanine dichromophores-labeled poly (aryl ether) dendrimer: synthesis,characterization and photoinduced energy transfer

A series of benzophenone chromospheres and zinc(II) phthalocyanine dichromophores labeled poly (aryl benzyl ether) dendrimer (G_n-DZnPc(BP)_8n, n = 1?2) were synthesized. Their structures were characterized by elemental analysis, ¹H NMR, IR, UV–vis and matrix-assisted laser desorption/ionization time-of-flight spectrometry (MALDI-TOF MS). Their photophysical properties were examined by steady-state and time-resolved fluorescence methods. Both the poly (aryl benzyl ether) dendrimer and BP terminal chromophores had a significant effect on photophysical properties of the zinc(II) phthalocyanine core. Time-resolved spectroscopic measurements indicated that the lifetime of benzophenone (donor) chromophore was longer than that of the zinc(II) phthalocyanine (acceptor). The fluorescence of the peripheral benzophenone chromophores was quenched by the phthalocyanine group attached to the focal point. All of these observations suggest that an intramolecular singlet energy transfer occurs in G_n-DZnPc(BP)_8n molecules. The light-harvesting abilities of these molecules increased with generations due to an increase in the number of benzophenone chromophores. The energy transfer efficiencies were ca. 0.49 and 0.68 for generations 1 and 2, respectively, and the rate constants of the singlet-singlet energy transfer were ca. 10⁸ s^?1. The rate constants changed inconspicuously with increase of dendron generations. The intramolecular singlet-singlet energy transfer is proposed to proceed mainly via a Förster-type interaction mechanism involving the dendrimer backbone as a scaffold to hold the peripheral benzophenone chromophores and the phthalocyanine core together. This dendrimer was an effective new energy transmission complex with high efficiency and could be used as a potential light-harvesting system.     

Exciplex formation in aromatic copolymers and photoinduced electron transfer from exciplex to acceptor

The exciplex formation in 9-vinylphenanthrene-p-N,N-dimethylaminostyrene copolymers, its characteristics, and the electron transfer process in polar solvents were studied. The copolymer exhibited a more intense intramolecular exciplex fluorescence than the low-molecular-weight model system, phenanthrene-N,N-dimethylaniline, in which the intermolecular exciplex formation occurred. Intensities of the exciplex fluorescence, which were unchanged regardless of the copolymer composition, led us to speculate that the efficient energy migration takes place from an excited phenanthrene unit to an exciplex forming site on the polymer chain. The electron transfer in the copolymer-p-dicyanobenzene system was studied in polar media. The formation of p-dicyanobenzene anion radical was measured by flash photolysis and electron spin resonance (ESR). p-Dicyanobenzene anion radical was generated by the electron transfer process via exciplex and the direct electron transfer process from the excited phenanthrene unit in the copolymer.     

Energy transfer kinetics of phycoerythrocyanins (PECs) from the cyanobacteriumAnabaena variabilis (I)

The exritation energy transfer processes in monomeric phycoerythrocyanins (PEC) have been studied in detail using steady-state and time-resolved fluorescence spectra techniques as well as the deconvolution tech-nique of spectra. The results indicate that the energy transfer processes should take place between α₈₄,-PVB and β₈₄- or β₁₅₅-PCB chromophores. the time constants of energy transfer are 34.7 and 130 ps individually; the component with lifetime of 1.57 ns originates from the fluorescence lifetime of the terminal emitter of β₈₄- and /or β₁₅₅ -PCB chro-mophores; and the component with lifetime of 515 ps might be assigned to the energy transfer between two PCB chro-mophores of β subunit. Project supported by the National Natural Science Foundation of China.     

Synthesis and fluorescence properties of novel benzo[a]phenoxazin-5-one derivatives

Thirteen, benzo[a]phenoxazin-5-one derivatives 3a-m were synthesized from 4-nitrosoaniline hydrochlorides 1a-m and ethyl 1,3-dihydroxynaphthoate 2 and their fluorescence properties were discussed in terms of the electronic effect of substituents. A coupling reaction was carried out with 6-carbethoxy-9-N-(2-hydroxyethyl)-N-methylamino-5H-benzo[a]phenoxazin-5-one (3k) and acetyl-DL-alanine to afford N-[(6-carbethoxy-5-oxo-5H-benzo[a]phenoxazin)-9-yl]-N-methylaminoethylene acetyl-DL-alanine ester (4).     

Energy transfer in calixarene-based cofacial-positioned perylene bisimide arrays

The synthesis of multichromophoric perylene bisimide-calix[4]arene arrays with up to five perylene units (containing orange, violet, and green perylene bisimide chromophores) and of monochromophoric model compounds was achieved by subsequent imidization of mono-Boc functionalized calix[4]arene linkers with three different types of perylene bisimide dye units. The optical properties of all compounds were studied with UV/vis absorption and steady state and time-resolved fluorescence spectroscopy. Upon excitation of the inner orange dye at 490 nm of array 3, strong fluorescence emission of the outer green perylene bisimide (PBI) chromophore at 744 nm is observed. The fluorescence excitation spectra of compounds 3 and 4 (lambdadet = 850 nm) show all absorption bands of the parent chromophores (e.g., all perylene units contribute to the emission from S1 state of the green PBI). Thus, the fluorescence emission and excitation spectra as well as time-resolved data of fluorescence lifetimes in the absence (tauD = 5.1 ns) and in the presence of an acceptor (tauDA = 0.8 ns) suggest efficient energy transfer processes between the perylene bisimide dye units. For the bichromophoric array 4, the energy transfer rate is calculated to a value of 1.05 x 109 s-1. These results demonstrate highly efficient energy transfer in cofacially assembled dye arrays.     

Synthesis and Structure-Photophysics Evaluation of 2-N-Amino-quinazolines: Small Molecule Fluorophores for Solution and Solid State

2-N-aminoquinazolines were prepared by consecutive S_NAr functionalization. X-ray structures display the nitrogen lone pair of the 2-N-morpholino group in conjugation with the electron deficient quinazoline core and thus representing electronic push-pull systems. 2-N-aminoquinazolines show a positive solvatochromism and are fluorescent in solution and in solid state with quantum yields up to 0.73. Increase in electron donor strength of the 2-amino substituent causes a red-shift of the intramolecular charge transfer (ICT) band (300–400 nm); whereas the photoluminescence emission maxima (350–450 nm) is also red-shifted significantly along with an enhancement in photoluminescence efficiency. HOMO-LUMO energies were estimated by a combination of electrochemical and photophysical methods and correlate well to those obtained by computational methods. ICT properties are theoretically attributed to an excitation to Rydberg-MO in SAC-CI method, which can be interpreted as n-π* excitation. 7-Amino-2-N-morpholino-4-methoxyquinazoline responds to acidic conditions with significant increases in photoluminescence intensity revealing a new turn-on/off fluorescence probe.     

Donor–Acceptor (D–A)‐Substituted Polyyne Chromophores: Modulation of Their Optoelectronic Properties by Varying the Length of the Acetylene Spacer

A series of donor–acceptor‐substituted alkynes, 2 a – f , was synthesized in which the length of the π‐conjugated polyyne spacer between the N,N‐diisopropylanilino donor and the 1,1,4,4‐tetracyanobuta‐1,3‐diene (TCBD) acceptor was systematically changed. The effect of this structural change on the optoelectronic properties of the molecules and, ultimately, their third‐order optical nonlinearity was comprehensively investigated. The branched N,N‐diisopropyl groups on the anilino donor moieties combined with the nonplanar geometry of 2 a – f imparted exceptionally high solubility to these chromophores. This important property allowed for performing INADEQUATE NMR measurements without ¹³C labeling, which, in turn, resulted in a complete assignment of the carbon skeleton in chromophores 2 a – f and the determination of the ¹³C–¹³C coupling constants. This body of data provided unprecedented insight into characteristic ¹³C chemical shift patterns in push–pull‐substituted polyynes. Electrochemical and UV/Vis spectroscopic studies showed that the HOMO–LUMO energy gap decreases with increasing length of the polyyne spacer, while this effect levels off for spacers with more than four acetylene units. The third‐order optical nonlinearity of this series of molecules was determined by measuring the rotational averages of the third‐order polarizabilities (γ_rot) by degenerate four‐wave mixing (DFWM). These latter studies revealed high third‐order optical nonlinearities for the new chromophores; most importantly, they provided fundamental insight into the effect of the conjugated spacer length in D–A polyynes, that can be exploited in the future design of suitable charge‐transfer chromophores for applications in optoelectronic devices.     

Synthesis and photoluminescent properties of 7-N,N-diphenylamino-3- benzoheterocyclic coumarin derivatives

Two new 7-N,N-diphenylamino-3-benzoheterocyclic coumarin derivatives containing electron-transporting benzotriazolyl or benzoxazolyl moiety, 3-(1-benzotriazole)-7-N,N-diphenylaminocoumarin (BTDC) and 3-(2-benzoxazole)-7-N,N-diphenylaminocoumarin (BODC), were synthesized and characterized by element analysis, ¹H NMR and FT-IR spectra. The UV–vis and fluorescence spectra of these coumarin derivatives were investigated. The results show that BTDC and BODC exhibit strong blue and red emissions, respectively, under ultraviolet light excitation. The relationships between the chemical structure and the fluorescence characteristics of the 7-N,N-diphenylamino-3-benzoheterocyclic coumarin derivatives are discussed. It was found that the coumarin derivative will become a high-efficiency emitting material when an amino group is attached in 7-position of the coumarin ring, and 7- strong electron donors can improve the ability of the intramolecular charge transfer of the coumarin molecules.     

Enhanced Light‐Harvesting Capacity by Micellar Assembly of Free Accessory Chromophores and LH1‐like Antennas

Biohybrid light‐harvesting antennas are an emerging platform technology with versatile tailorability for solar‐energy conversion. These systems combine the proven peptide scaffold unit utilized for light harvesting by purple photosynthetic bacteria with attached synthetic chromophores to extend solar coverage beyond that of the natural systems. Herein, synthetic unattached chromophores are employed that partition into the organized milieu (e.g. detergent micelles) that house the LH1‐like biohybrid architectures. The synthetic chromophores include a hydrophobic boron‐dipyrrin dye (A1) and an amphiphilic bacteriochlorin (A2), which transfer energy with reasonable efficiency to the bacteriochlorophyll acceptor array (B875) of the LH1‐like cyclic oligomers. The energy‐transfer efficiencies are markedly increased upon covalent attachment of a bacteriochlorin (B1 or B2) to the peptide scaffold, where the latter likely acts as an energy‐transfer relay site for the (potentially diffusing) free chromophores. The efficiencies are consistent with a Förster (through‐space) mechanism for energy transfer. The overall energy‐transfer efficiency from the free chromophores via the relay to the target site can approach those obtained previously by relay‐assisted energy transfer from chromophores attached at distant sites on the peptides. Thus, the use of free accessory chromophores affords a simple design to enhance the overall light‐harvesting capacity of biohybrid LH1‐like architectures.