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![Temperature-activated delayed fluorescence: system and processes
a [Cu4(PCP)3]⁺ (PCP = 2,6-(PPh2)2C6H3) complex. b Scheme of light emission from Cu-based OLEDs due to temperature-activated delayed fluorescence (TADF) under electroluminescence conditions. After electron-hole recombination, the singlet and triplet excited states are occupied in a 1:3 ratio due to one possible momentum projection in the singlet and three possible projections in the triplet state. If the energy of the triplet state T1 is close to the energy of the singlet S1, temperature-activated reverse intersystem crossing (T1 → S1) occurs which is followed by light emission from the singlet state. c Structure of [Cu4(PCP)3]⁺ derived from single crystal X-ray diffraction. Cu atoms are brown, P atoms are magenta, C atoms are gray, H atoms are not shown. d Schematic illustration showing that non-radiative relaxation paths in Cu OLED materials are more probable if equilibrium excited and ground state structures are displaced along some vibrational coordinates. e Green emission from an OLED prototype with [Cu4(PCP)3]⁺ as a luminophore.](publication/341087551/figure/fig1/AS:959165119868937@1605694193103/Temperature-activated-delayed-fluorescence-system-and-processes-a-Cu4PCP3.png)
Temperature-activated delayed fluorescence: system and processes a [Cu4(PCP)3]⁺ (PCP = 2,6-(PPh2)2C6H3) complex. b Scheme of light emission from Cu-based OLEDs due to temperature-activated delayed fluorescence (TADF) under electroluminescence conditions. After electron-hole recombination, the singlet and triplet excited states are occupied in a 1:3 ratio due to one possible momentum projection in the singlet and three possible projections in the triplet state. If the energy of the triplet state T1 is close to the energy of the singlet S1, temperature-activated reverse intersystem crossing (T1 → S1) occurs which is followed by light emission from the singlet state. c Structure of [Cu4(PCP)3]⁺ derived from single crystal X-ray diffraction. Cu atoms are brown, P atoms are magenta, C atoms are gray, H atoms are not shown. d Schematic illustration showing that non-radiative relaxation paths in Cu OLED materials are more probable if equilibrium excited and ground state structures are displaced along some vibrational coordinates. e Green emission from an OLED prototype with [Cu4(PCP)3]⁺ as a luminophore.
Source publication
![Pump-probe Cu K-edge X-ray absorption of [Cu4(PCP)3]⁺
a Experimental Cu...](publication/341087551/figure/fig2/AS:959165119868951@1605694193354/Pump-probe-Cu-K-edge-X-ray-absorption-of-Cu4PCP3-a-Experimental-Cu-K-edge-transient_Q320.jpg)
![Pump-probe P Kα X-ray emission spectroscopy for [Cu4(PCP)3]⁺
a Scheme...](publication/341087551/figure/fig3/AS:959165119873034@1605694193506/Pump-probe-P-Ka-X-ray-emission-spectroscopy-for-Cu4PCP3-a-Scheme-of-the-pump-probe-P_Q320.jpg)
![Pump-probe X-ray scattering for [Cu4(PCP)3]⁺
Experimental pump-probe...](publication/341087551/figure/fig4/AS:959165119877126@1605694193678/Pump-probe-X-ray-scattering-for-Cu4PCP3-Experimental-pump-probe-X-ray-scattering_Q320.jpg)
OLED technology beyond small or expensive devices requires light-emitters, luminophores, based on earth-abundant elements. Understanding and experimental verification of charge transfer in luminophores are needed for this development. An organometallic multicore Cu complex comprising Cu–C and Cu–P bonds represents an underexplored type of luminopho...
Citations
... The ID09 beamline is mainly dedicated to time-resolved X-ray scattering/diffraction studies of ultrafast phenomena [23,35], in a wide variety of systems, including chemical [36][37][38] or biological reactions [39,40] involving light-sensitive molecules dissolved in solution, light-induced phase transitions in solid-state samples [41,42], or laser-induced structural changes in colloidal systems [43]. As discussed in the current manuscript, we have now expanded the capabilities of the beamline to the study of laser-shock compressed samples by the X-ray diffraction technique [24,25]. ...
... The Aramis tender-to-hard X-ray branch of SwissFEL at the Paul Scherrer Institute has been in user operation since 2017 Prat et al., 2020). It enables time-resolved experiments which are of vital interest in the investigation of the world's current most important functional materials, such as catalysts, ultrafast electronic switches, high-capacity storage media, and molecular complexes of chemical and biological relevance (Milne et al., 2014;Ingold et al., 2019;Smolentsev et al., 2020). Common to these experiments is the critical importance of time resolution by synchronizing the X-ray pulse and a probing or perturbing laser pulse. ...
To fully exploit ultra-short X-ray pulse durations routinely available at X-ray free-electron lasers to follow out-of-equilibrium dynamics, inherent arrival time fluctuations of the X-ray pulse with an external perturbing laser pulse need to be measured. In this work, two methods of arrival time measurement were compared to measure the arrival time jitter of hard X-ray pulses. The methods were photoelectron streaking by a THz field and a transient refractive index change of a semiconductor. The methods were validated by shot-to-shot correction of a pump–probe transient reflectivity measurement. An ultimate shot-to-shot full width at half-maximum error between the devices of 19.2 ± 0.1 fs was measured.
... Non-resonant XES has been widely used to investigate ultrafast processes in liquid phase systems (Zhang et al., 2014;Mara et al., 2017;Zhang et al., 2017;Kunnus et al., 2020;Naumova et al., 2020a,b;Smolentsev et al., 2020). The majority of those studies were performed using dispersive high-resolution X-ray spectrometers operating in von Hamos geometry. ...
The Femtosecond X-ray Experiments (FXE) instrument at the European X-ray Free-Electron Laser (EuXFEL) provides an optimized platform for investigations of ultrafast physical, chemical and biological processes. It operates in the energy range 4.7–20 keV accommodating flexible and versatile environments for a wide range of samples using diverse ultrafast X-ray spectroscopic, scattering and diffraction techniques. FXE is particularly suitable for experiments taking advantage of the sub-MHz repetition rates provided by the EuXFEL. In this paper a dedicated setup for studies on ultrafast biological and chemical dynamics in solution phase at sub-MHz rates at FXE is presented. Particular emphasis on the different liquid jet sample delivery options and their performance is given. Our portfolio of high-speed jets compatible with sub-MHz experiments includes cylindrical jets, gas dynamic virtual nozzles and flat jets. The capability to perform multi-color X-ray emission spectroscopy (XES) experiments is illustrated by a set of measurements using the dispersive X-ray spectrometer in von Hamos geometry. Static XES data collected using a multi-crystal scanning Johann-type spectrometer are also presented. A few examples of experimental results on ultrafast time-resolved X-ray emission spectroscopy and wide-angle X-ray scattering at sub-MHz pulse repetition rates are given.
... No imaginary frequencies showed that both the first excited states are stable configurations. The following calculations based on their optimized geometries of the ground and excited states were performed with TPSS, 25 Cam-B3LYP, 26 ωB97XD, 27 and PBE functionals 28 to assess the absorption and emission properties. Further, the luminous mechanism has been explored with the quantum dynamical model. ...
A highly selective probe for copper(II) detection based on the dansyl group was theoretically studied by means of (time-dependent) density functional theory. The calculated results indicated that the oscillator strength of the fluorescent process for the probe molecule is considerably large, but the counterpart of its copper(II) complex is nearly zero; therefore, the predicted radiative rate kr of the probe is several orders of magnitude larger than that of its complex; however, the predicted internal conversion rate kic of both the probe and its complex is of the same order of magnitude. In addition, the simulated intersystem crossing rate kisc of the complex is much greater than that of the probe due to the effect of heavy atom from the copper atom in the complex. Based on the above information, the calculated fluorescence quantum yield of the probe is 0.16% and that of the complex becomes 10-6%, which implies that the first excited state of the probe is bright state and that of the complex is dark state. For the complex, the hole-electron pair analysis indicates that the process of S0 → S1 belongs to metal-to-ligand charge transfer; its density-of-state diagram visually illustrates that the highest occupied molecular orbital (HOMO) contains the ingredient of the s orbital from the copper atom, which decreases the frontier orbital energy level and the overlap integral of HOMO and LUMO.
... The goal is to be able to follow structural changes taking place in a sample as a function of time after a given reaction-triggering event (Fig. 7, [63]). Phenomena that are routinely investigated at ID09 are chemical [64,65] or biological reactions [66,67] involving light-sensitive molecules dissolved in solution, light-induced phase transitions in solid-state samples [21,68], or laserinduced structural changes in colloidal systems [69]. These phenomena can be tracked as a function of time with 100 ps resolution up to seconds (or more). ...
The Complex System and Biomedical Sciences (CBS) group at the European Synchrotron Radiation Facility (ESRF) in Grenoble is dedicated to the study of a broad family of materials and systems, including soft and hard condensed matter, nanomaterials, and biological materials. The main experimental methods are in the domain of scattering techniques, i.e., X-ray diffraction, reflectivity, scattering, photon correlation spectroscopy, and time-resolved X-ray scattering/diffraction. After the recent and successful upgrade of the storage ring, the ESRF Extremely Brilliant Source (EBS) has become the first high-energy synchrotron in the world of the 4th generation, which offers unprecedented beam parameters for its user community, bringing new experimental opportunities for the exploration of the nanoscale structure, kinetics, and dynamics of a myriad of systems. In this contribution, we present the impact of the recent upgrade on the selected beamlines in the CBS group and a summary of recent scientific activities after the facility reopening.
... Currently the following three endstations are in user operations: • Alvra: Hard X-ray endstation with a focus on photo-chemistry and -biology. Specific strength of the endstation for chemical applications include ultrafast absorption and emission spectroscopy in the tender to hard x-ray regime for molecular systems and nanoparticles in solution [26,27]. For photobiology, a lipidic cubic phase (LCP) injector combined with a 16 megapixel Jungfrau pixel detector enables time-resolved serial femtosecond crystallography with time resolution of tens of femtoseconds and pump-probe delays ranging from the femtosecond to the millisecond scale [10]. ...
At the Paul Scherrer Institute, two electron accelerator-based photon sources are in operation, namely a synchrotron source, the swiss light source (SLS), and an X-ray free-electron laser, SwissFEL. SLS has been operational since 2001 and SwissFEL since 2017. In this time, unique and world-leading scientific programs and methods have developed from the SLS and the SwissFEL in fields as diverse as macromolecular biology, chemical and physical sciences, imaging, and the electronic structure and behaviour of novel and complex materials. To continue the success, a major upgrade of SLS, the SLS2.0 project, is ongoing and at SwissFEL further endstations are under construction.
... En los últimos años se ha incrementado el desarrollo de materiales para óptica no lineal (Taboukhat et al., 2020) y para la fabricación de dispositivos como OLEDs (por sus siglas en inglés, Organic Light Emitting Diodes) y celdas solares (Liu et al., 2020;Smolentsev et al., 2020). Entre otras características que deben cumplir los materiales con potencial uso en optoelectrónica, destaca el rol de los orbitales frontera, que determinan la viabilidad de ser incluidos en la arquitectura de un dispositivo optoelectrónico (Zhou, 2018). ...
Se reporta la determinación de los orbitales frontera (HOMO y LUMO) de un par de compuestos organometálicos (PdCl2L y PdBr2L). Este tipo de compuestos han cobrado gran interés por sus prometedores propiedades y aplicación en optoelectrónica, ya que combinan las ventajas de los materiales orgánicos e inorgánicos, su potencial uso está determinado en gran parte por los valores de sus orbitales frontera. Entre los métodos utilizados para conocer esta información, se considera a la voltamperometría cíclica, la cual permite determinar de forma indirecta dichos niveles de energía mediante la determinación los potenciales del comienzo de los procesos de oxidación y reducción de las moléculas en estudio. Los complejos PdCl2L y PdBr2L fueron caracterizados por el método mencionado, con los datos obtenidos se procedió al cálculo de los orbitales frontera y el bandgap. De acuerdo con los resultados, los valores se encuentran dentro del rango reportado para semiconductores, indicando que los complejos son viables para ser empleados en la fabricación de dispositivos optoelectrónicos.
... The goal is to be able to follow structural changes taking place in a sample as a function of time after a given reaction-triggering event (Fig. 7, [58]). Phenomena that are routinely investigated at ID09 are chemical [59,60] or biological reactions [61,62] involving light-sensitive molecules dissolved in solution, light-induced phase transitions in solid-state samples [21,63], or laser-induced structural changes in colloidal systems [64]. These phenomena can be tracked as a function of time with 100 ps resolution up to seconds (or more). ...
The Complex System and Biomedical Sciences (CBS) group at the European Synchrotron Radiation Facility (ESRF) in Grenoble is dedicated to the study of a broad family of materials and systems, including soft and hard condensed matter, nanomaterials, and biological materials. The main experimental methods used for this purpose are X-ray diffraction, reflectivity, scattering, photon correlation spectroscopy, and time-resolved X-ray scattering/diffraction. After a recent and successful Extremely Brilliant Source (EBS) upgrade, the Grenoble synchrotron has become the first of the 4th generation high energy facilities, which offers unprecedented beam parameters for its user community, bringing new experimental opportunities for the exploration of the nanoscale structure, kinetics, and dynamics of a myriad of systems. In this contribution, we present the impact of the recent upgrade on the selected beamlines in the CBS group and a summary of recent scientific activities after the facility reopening.
... Luminescent cuprous complexes are some of the most promising new materials because of their strong solid-state emission and easy accessibility (Troyano et al., 2021;Smolentsev et al., 2020;Mondal et al., 2019;Czerwieniec et al., 2016). Metal complexes and their luminescence have been studied with respect to many aspects and notably some species have been found to show excellent application performance based on their luminescence, for uses such as lighting, display, messaging, etc. ...
Luminescent cuprous complexes are of great importance among coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title heteroleptic cuprous polymer solvate, catena-poly[[[(9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)-κ²P,P′](μ-pyridine-3-carbonitrile-κ²N¹:N³)copper(I)] hexafluorophosphate dichloromethane trisolvate], {[Cu(C6H4N2)(C39H32OP2)]PF6·3CH2Cl2}n, conventionally abbreviated as {[Cu(3-PyCN)(Xantphos)]PF6·3CH2Cl2}n, where Xantphos and 3-PyCN represent (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) and pyridine-3-carbonitrile, respectively, has been described. In this polymer solvate, the asymmetric unit consists of three dichloromethane solvent molecules, a hexafluorophosphate anion and a polymeric heteroleptic cuprous complex cation, in which the cuprous centre is in a CuP2N2 tetrahedral coordination and is coordinated by two P atoms from the Xantphos ligand and two N atoms from two 3-PyCN ligands (the pyridyl and cyano N atoms). It is through the connection of the μ2-bridging 3-PyCN ligand that these cuprous centres are linked into a one-dimensional helical chain structure. The chains are further assembled through C—H⋯π interactions to form a supramolecular metal–organic framework containing solvent-accessible channels. The UV–Vis absorption and photoluminescence properties of this heteroleptic cuprous polymer have been studied on as-synthesized samples. Its luminescence emission should mainly originate from the metal-to-ligand charge transfer excited state.
... Three pump-probe X-ray techniques, namely X-ray absorption spectroscopy near Cu K-edge, X-ray emission spectroscopy at the P Kα line and solution-state X-ray scattering were used to investigate the [Cu 4 (PCP) 3 ] + cluster upon photo-excitation in solution. [101] The experimental data allowed to address the above-mentioned questions for the triplet excited state. The results of the pump-probe X-ray absorption measurements are presented in Figure 7c. ...
... (c) Cu K-edge X-ray absorption spectrum for the ground state (red line) and pump-probe X-ray absorption spectrum (black line) corresponding to 1 μs time window after photoexcitation. Adapted under terms of the CC-BY license from Ref.[101]. Copyright 2020, The Authors, published by Springer Nature. ...
Organic light‐emitting diodes (OLEDs) are employed in innovative display technologies and have the potential to be used widely in large area lighting. Luminophores containing 4d or 5d metals are efficient in electro‐luminescent devices due to their phosphorescent properties but are scarce and expensive. Alternatives take advantage of temperature‐activated delayed fluorescence (TADF), e. g. in Cu(I) complexes. We show modern X‐ray spectroscopy methods exemplified on Ru, Ir and Cu‐based luminophores offering insight into the capabilities of such techniques to researchers from various fields. Knowledge of structural rearrangements in the excited state is crucial to understand non‐radiative energy losses and to develop efficient luminophores. Pump‐probe X‐ray absorption spectroscopy (XAS) gives information about the molecular structure in the excited state and the electronic structure. We show how this information can be complemented with X‐ray emission spectroscopy at X‐ray free‐electron lasers (XFEL) and discuss the potential of time‐resolved X‐ray excited optical luminescence (TR‐XEOL) to provide additional selectivity of XAS to luminescent sites.
