The intermediate coupling regime for electronic energy transfer is of particular interest because excitation moves in space, as a classical hopping mechanism, but quantum phase information conserved. We conducted an ultrafast polarization experiment specifically designed to observe coherent dynamics this regime. Conjugated polymer samples with different chain conformations were examined model multichromophoric systems. data, recorded at room temperature, reveal intrachain (but not...

Singlet oxygen sensitization by organic molecules is a topic of major interest in the development both efficient photodynamic therapy (PDT) and aerobic oxidations under complete green chemistry conditions. We report on design, synthesis, biology, spectroscopic characterization (vis-NIR linear two-photon absorption spectroscopy, singlet generation efficiencies for one- excitation, electrochemistry, intrinsic dark toxicity, cellular uptake, subcellular localization) three classes innovative...

In this work we report a study of the role coherence dynamics in intermediate coupling regime electronic energy transfer (EET). Starting from idea that phase information should be partially retained process donor to an acceptor, designed new ultrafast experiment based on anisotropy decay along two time axes, capable probing degree characterizing transfer. Conjugated polymer (poly[2-methoxy-5-(2′-ethyl-hexoxy)-1,4-phenylenevinylene], MEH-PPV) samples with different chain conformations were...

Abstract The development of a solution‐deposited up‐converted distributed feedback laser prototype is presented. It employs sol–gel silica/germania soft‐lithographed microcavity and CdSe–CdZnS–ZnS quantum dot/sol–gel zirconia composites as optical gain material. Characterization the linear nonlinear properties dots establishes their high absorption cross‐sections in one‐ two‐ photon regimes to be 1 × 10 −14 cm 2 5 4 GM, respectively. In addition, ultrafast transient dynamics measurements...

In the search of new materials characterized by high two-photon absorption (TPA) efficiency, many efforts have been devoted to design chromophores with enhanced TPA responses progressively moving from linear such as dipoles and quadrupoles toward multimeric complex molecular architectures. This approach is mainly based on optimization intra-molecular charge transfer interactions. contrast extensive investigations this intramolecular approach, effect inter-molecular interactions has not fully...

Observation of coherent oscillations in the 2D electronic spectra (2D ES) photosynthetic proteins has led researchers to ask whether nontrivial quantum phenomena are biologically significant. Coherent have been reported for soluble light-harvesting phycobiliprotein (PBP) antenna isolated from cryptophyte algae. To probe link between spectral properties and protein structure, we determined crystal structures three PBP complexes different species. Each is a dimer αβ subunits which structure...

2D electronic spectroscopy is a widely exploited tool to study excited state dynamics. A high density of information enclosed in spectra. crucial challenge objectively disentangle all the features third order optical signal. We propose global analysis method based on variable projection algorithm, which able reproduce simultaneously coherence and population dynamics rephasing non-rephasing contributions. Test measures at room temperature standard dye are used validate procedure discuss...

The performance of nonfullerene-acceptor-(NFA)-based organic solar cells is rapidly approaching the efficiency inorganic cells. chemical versatility NFAs extends light-harvesting range to infrared, while preserving a considerably high open-circuit-voltage, crucial achieve power-conversion efficiencies >17%. Such low voltage losses in charge separation process have been attributed low-driving-force and efficient exciton dissociation. Here, we address nature subpicosecond dynamics...

Abstract The subtle details of the mechanism energy flow from carotenoids to chlorophylls in biological light-harvesting complexes are still not fully understood, especially ultrafast regime. Here we focus on antenna complex peridinin–chlorophyll a –protein (PCP), known for its remarkable efficiency excitation transfer carotenoids—peridinins—to chlorophylls. PCP solutions studied by means 2D electronic spectroscopy different experimental conditions. Together with global kinetic analysis and...

Time-frequency decomposition techniques, borrowed from the signal-processing field, have been adapted and applied to analysis of 2D oscillating signals.While Fourier-analysis techniques available so far are able interpret information content signal only in terms its frequency components, time-frequency transforms (TFT) proposed this work can instead provide simultaneously time resolution, unveiling dynamics relevant beating supplying a valuable help their interpretation.In order fully...

One of the most recent developments at forefront nanotechnology is attempt to exploit quantum phenomena in nanometer scale materials, exploring novel applications effects. An effective exploitation must necessarily pass through a deep understanding how generate, manipulate, and characterize coherent superposition states nanosystems. However, despite lively interest this topic, study effects nanomaterials still represents relatively unexplored territory. Here we report an investigation on...

In this study, we used two-dimensional electronic spectroscopy to examine the early femtosecond dynamics of suspensions colloidal gold nanorods with different aspect ratios. all samples, signal distribution in 2D maps at timescale shows a distinctive dispersive behavior, which can be explained by interference between exciting field and produced on nanoparticle's surface collective motion electrons when plasmon is excited. Studying effect, active only until has been dephased, allows for...

Self-assembled organic chromophores form nanostructures in solutions, with their molecular packing determining the optoelectronic properties and photocatalytic activity. Here we report an dye molecule, 1,3,6,8-tetrakis(4-ethynylbenzoic acid)pyrene (TEBAPy), that exhibits two aggregate states aqueous conditions: nanofibers or nanoparticles depending on charge-screening conditions. The promote sacrificial hydrogen production (H2, 84 mmol g–1 h–1) while produce peroxide (H2O2, 71 h–1). Using a...

The microwave-enhanced synthesis, comparative singlet oxygen sensitization efficiency, and nonlinear optical characterization of a new β-functionalized porphyrin its copper complex are described. We show that the introduction donor−acceptor push−pull conjugated fragment in β position strongly perturbs electronic structure leading to remarkable one- two-photon NIR absorption enhancement.

The intraband exciton dynamics of molecular aggregates is a crucial initial step to determine the possibly coherent nature energy transfer and its implications for ensuing interband relaxation pathways in strongly coupled excitonic systems. In this work, we fully characterize linear J-aggregates porphyrins, good model systems multichromophoric assemblies biological antenna complexes. Using different 2D electronic spectroscopy schemes together with Raman theoretical modeling, provide full...

Two-dimensional electronic spectroscopy based on passive phase stabilization methods is now well known and widely employed worldwide.In the most recent fully non-collinear implementations, a great stability often achieved at expense of independent control over pulse timings, limiting full potential technique.Here we propose several modifications in experiment geometry, calibration procedures, data acquisition processing routines.The setup easily tunable to record different phase-matching...

The non-radiative relaxation of the excitation energy from higher states to lowest state in chlorophylls is a crucial preliminary step for process photosynthesis. Despite continuous theoretical and experimental efforts clarify ultrafast dynamics this process, it still represents object an intense investigation because timescale congestion involved makes its characterization particularly challenging. Here we exploit 2D electronic spectroscopy recently developed data analysis tools provide...

In this work, we demonstrate the use of two-dimensional electronic spectroscopy (2DES) to study mechanism and time scale femtosecond Stokes shift dynamics in molecules characterized by intramolecular charge transfer, such as distyryl-functionalized boron dipyrromethene (BODIPY) molecules. The obtained results that 2DES allows clear direct visualization phenomenon. analysis 2D data terms frequency-frequency decay associated maps provides indeed not only relaxation process but also starting...

The full blossoming of quantum technologies requires the availability easy-to-prepare materials where coherences can be effectively initiated, controlled, and exploited, preferably at ambient conditions. Solid-state multilayers colloidally grown dots (QDs) are highly promising for this task because possibility assembling networks electronically coupled QDs through modulation sizes, inter-dot linkers, distances. To usefully probe coherence in these materials, dynamical characterization their...