Free-Space distribution of entanglement and single photons over 144 km

Quantum Entanglement is the essence of quantum physics and inspires fundamental questions about the principles of nature. Moreover it is also the basis for emerging technologies of quantum information processing such as quantum cryptography, quantum teleportation and quantum computation. Bell's discovery, that correlations measured on entangled quantum systems are at variance with a local realistic picture led to a flurry of experiments confirming the quantum predictions. However, it is still experimentally undecided whether quantum entanglement can survive global distances, as predicted by quantum theory. Here we report the violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality measured by two observers separated by 144 km between the Canary Islands of La Palma and Tenerife via an optical free-space link using the Optical Ground Station (OGS) of the European Space Agency (ESA). Furthermore we used the entangled pairs to generate a quantum cryptographic key under experimental conditions and constraints characteristic for a Space-to-ground experiment. The distance in our experiment exceeds all previous free-space experiments by more than one order of magnitude and exploits the limit for ground-based free-space communication; significantly longer distances can only be reached using air- or space-based platforms. The range achieved thereby demonstrates the feasibility of quantum communication in space, involving satellites or the International Space Station (ISS).Comment: 10 pages including 2 figures and 1 table, Corrected typo

Effect of π-conjugation on electrochemical properties of poly(terthiophene)s 3′-substituted with fullerene C60

The series of copolymers based on terthiophene 3′-substituted with C60-pyrrolidine or styryl group, were electrochemically synthesized and characterized. The dense distribution of C60 side group caused the steric effects between them and the perturbation in the extent of π-electron delocalization of the poly(terthiophene) backbone. The ESR spectroscopy showed the presence of close-packed clusters especially in homopolymer: poly(terthiophene-C60). The oxidative electrochemical copolymerization of terthiophene units was performed to avoid this steric interactions and in results to extend the effective π-conjugation length in the polymer. The use of different ratio of the co-monomers contributed to the variable distribution of C60 unit and different effective π-conjugation of the resulting polymers. Those changes affected electrochemical and photocurrent-generating properties of these materials

Electrochemically synthesised xanthone-cored conjugated polymers as materials for electrochromic windows

In this work, we present the electrochemical polymerisation process of triarylamine-xanthone derivatives and behaviour of the formed polymers using various potentiodynamic techniques. The formed electropolymers have limited conjugation but show very promising electrochromic behaviour. Furthermore, by coupling the electrochemical analysis with each polymer's spectroscopic output, we were able to evaluate doping processes and the type of charge carriers formed. Through careful analysis, we were able to describe the electropolymerisation process and formed triarylamine-based polyxanthone derivatives. The polymers were found to exhibit good stability and good colouration efficiency to suggesting that they have potential application in electrochromic devices

Electrochemical and photoelectronic studies on C60-pyrrolidine- functionalised poly(terthiophene)

A novel donor-acceptor poly(terthiophene) derivative bearing a C60 pendant was electropolymerizated from N-methyl-2-(2-[4,4′\u27-didecyloxy-2,2′;5′,2′\u27]terthiophen-3′-yl-ethenyl)fullero[3,4]pyrrolidine (TTh-C60) solution. The electroreduction of TTh-C60 and poly(TTh-C60) showed the presence of complex peaks related to fulleropyrrolidine reduction. The dual nature of these redox couples may be related to increasing Coulombic repulsion or coupling between C60 substituents. Electrochemical, X-Ray photoelectron spectroscopy (XPS), Ultra-Violet photoelectron (UPS) and UV-Vis spectroscopy also confirm the nature of poly(TTh-C60). Electrochemical band gap of poly(TTh-C60) is 0.63 ± 0.20 eV in TBAP electrolyte and propylene carbonate (PC) solution. Furthermore, we obtained the value of optical energy band gap (Eopt = 0.59 ± 0.03 eV), the transport energy band gap (Egtrans = 1.17 ± 0.20 eV) and the exciton binding energy (Eb = 0.58 ± 0.20 eV) for poly(TTh-C60). The ionization energy values (IE) were determined using UPS spectroscopy (IE = 4.92 ± 0.10 eV) and electrochemical investigations of the poly(TTh-C60) polarized in TBAP/DCM (IE = 5.01 ± 0.10 eV) and TBAP/PC solution (IE = 4.95 ± 0.10 eV) demonstrating good coincidence of the value. The electrochemical method revealed, that the location of the Fermi level relative to the valence and conduction bands indicates p-type character of semiconducting poly(TTh-C60). On the other hand photoemission spectroscopy manifests n-type behavior of examined sample. In turn, the UV-Vis result showed that the charge transfer (CT) between poly(TTh) and C60 unit can suggest, that these chromophores are not entirely independent

Acridone-amine D-A-D thermally activated delayed fluorescence emitters with narrow resolved electroluminescence and their electrochromic properties

Acridones have found their role in luminescent materials for OLEDs. Most interestingly, showing potential as weak charge transfer thermally activated delayed fluorescence (TADF) emitters, providing narrow photoluminescence. In this work, we present a comprehensive study of donor-acceptor-donor (D-A-D) acridone-amine derivatives showing TADF and UV electrochromic properties. Structure-property relationships are studied using electrochemical and spectroelectrochemical methods as well as using photophysical characterization. Most successful emitters are used as luminescent materials in OLED, showing narrow (FWHM = 66-85 nm) electroluminescence in the green region with maximum EQE = 5.4%