Balanced homodyne detection in second-harmonic generation microscopy

We demonstrate the association of two-photon nonlinear microscopy with balanced homodyne detection for investigating second harmonic radiation properties at nanoscale dimensions. Variation of the relative phase between second-harmonic and fundamental beams is retrieved, as a function of the absolute orientation of the nonlinear emitters. Sensitivity down to approximately 3.2 photon/s in the spatio-temporal mode of the local oscillator is obtained. This value is high enough to efficiently detect the coherent second-harmonic emission from a single KTiOPO4 crystal of sub-wavelength size.Comment: 9 pages to appear in Applied Physics Letter

Surface-induced charge state conversion of nitrogen-vacancy defects in nanodiamonds

We present a study of the charge state conversion of single nitrogen-vacancy (NV) defects hosted in nanodiamonds (NDs). We first show that the proportion of negatively-charged NV$^{-}$ defects, with respect to its neutral counterpart NV$^{0}$, decreases with the size of the ND. We then propose a simple model based on a layer of electron traps located at the ND surface which is in good agreement with the recorded statistics. By using thermal oxidation to remove the shell of amorphous carbon around the NDs, we demonstrate a significant increase of the proportion of NV$^{-}$ defects in 10-nm NDs. These results are invaluable for further understanding, control and use of the unique properties of negatively-charged NV defects in diamondComment: 6 pages, 4 figure

Modulating the Framework Negative Charge Density in the System [BDT−TTP•+]/[Re6S5Cl91-]/[Re6(S/Se)6Cl82-]/[Re6S7Cl73-]

A series of 2D metals, β-(BDT-TTP)6[Re6Se6Cl8]·(CHCl2−CHCl2)2, 2; β-(ST-TTP)6[Re6S6Cl8]·(CH2Cl−CHCl2)2, 3; β-(BDT-TTP)7[Re6S6Cl8]0.5[Re6S7Cl7]0.5·(CH2Cl2), 4; β-(BDT-TTP)7[Re6Se6Cl8]0.5[Re6S7Cl7]0.5·(CH2Cl2), 5; β-(BDT-TTP)8[Re6S7Cl7]·(CH2Cl2)4, 6 (BDT-TTP and ST-TTP are 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene and 2-(1,3-diselenol-2-ylidene)-5(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, respectively) is reported to have one single β-slab layered topology despite successive increases of the cluster anion negative charge. The charge density within the templating composite inorganic−neutral molecule slab is shown to remain above a threshold of ca. one negative charge per square nanometer, that is, for cluster anions with two negative charges and higher. Conversely, discrete stacks are shown to be stabilized instead in the semiconducting salts (BDT-TTP)2[Re6S5Cl9], 1 where the cluster anion bears one negative charge only. The electronic structure of salts 2−6 is shown to be very stable and kept almost intact across the series. The templating strategy is shown to fulfill its anticipated potential for deliberate installment of incommensurate band fillings in molecular metals. The deliberate admixture of the 6:1 and 8:1 structures yields novel phases with a 7:1 stoichiometry with the anticipated crystal and electronic structures. The action at the organic−inorganic interface triggered by changing the anion charge yet keeping its shape and volume identical, which ultimately governs the shape of the unit cell, is of paramount importance in defining the Fermi surface of these metallic salts. The present BDT-TTP salts thus provide a series of materials with strongly related but subtly different Fermi surfaces worthy of many physical studies. Shubnikov−de Haas measurements are expected to be particularly interesting since they are especially sensitive to the details of the Fermi surface

Synthesis of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives functionalised with two, four or eight hydroxyl groups

Short synthetic routes to a range of BEDT-TTF derivatives functionalised with two, four or eight hydroxyl groups are reported, of interest because of their potential for introducing hydrogen bonding between donor and anion into their radical cation salts. The cycloaddition of 1,3-dithiole-2,4,5-trithione with alkenes to construct 5,6-dihydro-1,3-dithiolo[4,5-b]1,4-dithiin-2-thiones is a key step, with homo- or hetero-coupling procedures and O-deprotection completing the syntheses. The first synthesis of a single diastereomer of tetrakis(hydroxymethyl)BEDT-TTF, the cis, trans product, was achieved by careful choice of O-protecting groups to facilitate separation of homo- and hetero-coupled products. Cyclisation of the trithione with enantiopure 1R,2R,5R,6R-bis(O,O-isopropylidene)hex-3-ene-1,2,5,6-tetrol (from D-mannitol) gave two separable diastereomeric thiones, which can be transformed to enantiomeric BEDT-TTF derivatives with four or eight hydroxyl groups

Green Innovation: an empirical analysis of technology, skills and policy

[ES] Los resultados previsibles de la transición hacia economías con bajas emisiones de carbono son múltiples y afectan de diferentes maneras a los responsables del diseño y la gestión de las políticas públicas, las regiones del mundo, las empresas y los consumidores. Se ha reconocido que en el centro de esta transición están las innovaciones medioambientales que se desarrollan para mejorar la sostenibilidad a largo plazo del crecimiento económico. Los principales pilares de esta tesis son dos. En primer lugar, los desafíos ambientales son diversos, al igual que las respuestas que se necesitan para afrontarlos. La consecuencia principal de esto es que el enfoque actual en la tecnología verde como un bloque homogéneo de entidades indiferenciadas es engañoso. En segundo lugar, el trabajo humano es lo que en última instancia lleva a cabo la adaptación de los sistemas de producción y distribución. En consecuencia, analizar la transición hacia sociedades sostenibles desde un punto de vista medioambiental exige una comprensión profunda de cómo se diseñan, implementan y cambian las actividades laborales para acomodarse a nuevos imperativos políticos y / o nuevas oportunidades tecnológicas. Las evidencias empíricas sobre uno o ambos pilares son escasas o fragmentadas. La presente tesis trata de llenar estas lagunas desarrollando una base de datos global sobre ``patentes verdes'', una medida del ciclo de vida de las tecnologías y las consiguientes investigaciones para analizar la relación entre la producción de tecnologías verdes, las características del territorio y la base de competencias de la mano de obra en el tiempo y el espacio. El primer paso es la identificación de patentes verdes en PATSTAT 2016a utilizando la clasificación ENV-TECH (OECD, 2016) y geolocalizando sus inventores. El resultado es una base de datos que cubre la innovación mundial desde el siglo XIX hasta 2015, aunque el periodo estudiado es menor: 1970-2010. Este conjunto de datos permite una primera aproximación a la evolución de las tecnologías verdes en el tiempo y el espacio, donde podemos apreciar diferencias en la evolución de los países y entre las tecnologías desde el punto de vista de la complejidad, quizás relacionadas con la presencia de un cuerpo heterogéneo de tecnologías emergentes y maduras. Para entrar más a fondo en esta hipótesis, desarrollamos una metodología para medir las etapas del ciclo de vida de las tecnologías, y la utilizamos para entender los patrones de producción de tecnologías verdes a nivel de países. Encontramos que las capacidades son más importantes que la riqueza para diversificarse en innovación verde, y que las tecnologías maduras están positivamente asociadas con la especialización en estas tecnologías. Continuamos la exploración de la relación entre las capacidades locales, el ciclo de vida y la producción de patentes en los estados federales de Estados Unidos dónde descubrimos que la innovación verde esta más asociada con la recombinación de conocimientos distantes, en particular al principio del ciclo de vida. Finalmente, investigamos los efectos de las compras públicas sobre la innovación verde al nivel de las ``commuting zones'' (áreas urbanas funcionales) de Estados Unidos, tomando en cuenta de nuevo las capacidades locales, pero esta vez utilizando las competencias del mercado laboral en lugar de la variedad de la recombinación del conocimiento. Descubrimos que la compra pública verde tiene un efecto positivo y significativo, en particular en territorios con una parte importante de competencias abstractas en la población activa.[CA] Els resultats previsibles de la transició cap a economies baixes en emissions de carboni són múltiples i afecten de diferents maneres als responsables del disseny i la gestió de les polítiques públiques, les regions del món, les empreses i els consumidors. S'ha reconegut que en el centre d'aquesta transició estan les innovacions mediambientals que es desenvolupen per a millorar la sostenibilitat a llarg termini del creixement econòmic. Els principals pilars d'aquesta tesi són dos. En primer lloc, els desafiaments ambientals són diversos, igual que les respostes que es necessiten per a afrontar-los. La conseqüència principal d'això és que l'enfocament actual en la tecnologia verda com un bloc homogeni d'entitats indiferenciades és enganyós. En segon lloc, el treball humà és el que en última instància porta a terme l'adaptació dels sistemes de producció i distribució. En conseqüència, analitzar la transició cap a societats sostenibles des d'un punt de vista mediambiental exigeix una comprensió profunda de com es dissenyen, implementen i canvien les activitats laborals per a acomodar-se a nous imperatius polítics i / o noves oportunitats tecnològiques. Les evidències empíriques sobre un o ambdós pilars són escasses o fragmentades. La present tesi tracta d'omplir aquests buits desenvolupant una base de dades global sobre ``patents verdes'', una mesura del cicle de vida de les tecnologies i les consegüents investigacions per a analitzar la relació entre la producció de tecnologies verdes, les característiques del territori i la base de competències de la mà d'obra en el temps i l'espai. El primer pas és la identificació de patents verdes en PATSTAT 2016a utilitzant la classificació ENV-TECH (OECD, 2016) i la geolocalització dels seus inventors. El resultat és una base de dades que cobreix la innovació mundial des del segle XIX fins a 2015, encara que el període estudiat és menor: 1970-2010. Aquest conjunt de dades permet una primera aproximació a l'evolució de les tecnologies verdes en el temps i l'espai, on podem apreciar diferències en l'evolució dels països i entre les tecnologies des del punt de vista de la complexitat, probablement relacionades amb la presència d'un cos heterogeni de tecnologies emergents i madures. Per a entrar més a fons en aquesta hipòtesi, desenvolupem una metodologia per a mesurar les etapes del cicle de vida de les tecnologies, i la utilitzem per a entendre els patrons de producció de tecnologies verdes a nivell de països. Trobem que les capacitats són més importants que la riquesa per a diversificar-se en innovació verda, i que les tecnologies madures estan positivament associades amb l'especialització en aquestes tecnologies. També explorem la relació entre les capacitats locals, el cicle de vida i la producció de patents en els estats federals dels Estats Units on descobrim que la innovació verda està més associada amb la recombinació de coneixements distants, en particular al principi del cicle de vida. Finalment, investiguem els efectes de les compres públiques sobre la innovació verda al nivell de les ``commuting zones'' (àrees urbanes funcionals) dels Estats Units, prenent en compte de nou les capacitats locals, però aquesta vegada utilitzant les competències del mercat laboral en lloc de la varietat de la recombinació del coneixement. Descobrim que la compra pública verda té un efecte positiu i significatiu, en particular en territoris amb una part important de competències abstractes en la població laboral.[EN] The foreseeable outcomes of the transition towards low-carbon economies are multiple and affect in different ways policy-makers, world regions, firms and consumers. It has long been acknowledged that at the core of this transition stand environmental innovations which are developed to enhance the long-term sustainability of economic growth. The main pillars of this study are two. First, environmental challenges are different, and so are the responses that are needed to tackle them. The main consequence of this is that the current focus on green technology as a homogeneous block of undifferentiated entities is misleading. Second, the adaptation of production and distribution systems is ultimately carried through by human labour and analysing the transition to environmentally sustainable societies requires a thorough understanding of how work activities are designed, implemented and changed to accommodate new policy imperatives and/or new technological opportunities. Empirical evidence on either of these two pillars is scant or fragmented. The present thesis seeks to fill these gaps through the development of a database on green innovations, of a measure of the life cycle of green technologies, and of the corresponding explorations to scrutinize the relation between green technology production, the territories' characteristics and skills' base of labour market over time and space. The dataset is created identifying green patent in PATSTAT 2016a database using ENV-TECH classification (OECD, 2016) and geolocalizing their inventors. The result is a database covering green innovation worldwide from the 19$^{th}$ century to 2015, even if the period studied is smaller: 1970-2010. This dataset permits a first overview of green technologies evolution over time and space, where we can see differences in terms of country evolution and among technologies in terms of complexity, maybe related with the presence of an heteregeneous body of emerging and mature technologies. To explore further this hypothesis, we develop a methodology to measure technology life cycle stages, and we apply it to understand the patterns of evolution of green technology production at country level. We find that capabilities are more important than wealth to diversify in green innovation, and mature green technologies are positively associated with specialization. We continue the exploration of the relation between local capabilities, life cycle and patent activity in US federal states where we discover that green innovation is more associated than innovation in general with the recombination of distant knowledge, especially in early phases of the life cycle. Finally, we investigate at US commuting zones level the effects of public procurement on green innovation, taking into account local capabilities again, but using labour market skills instead of knowledge recombination variety. We find that green public procurement has a positive and significant effect, in particular in territories with an important share of abstract skills in labour population.Perruchas, F. (2019). Green Innovation: an empirical analysis of technology, skills and policy [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/119965TESI

Multistimuli Response Micro- and Nanolayers of a Coordination Polymer Based on Cu2I2 Chains Linked by 2-Aminopyrazine

This is the peer reviewed version of the following article: Conesa‐Egea, J., Gallardo‐Martínez, J., Delgado, S., Martínez, J. I., Gonzalez‐Platas, J., Fernández‐Moreira, V., ... & Amo‐Ochoa, P. Multistimuli Response Micro‐and Nanolayers of a Coordination Polymer Based on Cu2I2 Chains Linked by 2‐Aminopyrazine. Small 13.33 (2017): 1700965 , which has been published in final form at https://doi.org/10.1002/smll.201700965. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionA nonporous laminar coordination polymer of formula [Cu2I2(2-aminopyrazine)]n is prepared by direct reaction between CuI and 2-aminopyrazine, two industrially available building blocks. The fine tuning of the reaction conditions allows obtaining [Cu2I2(2-aminopyrazine)]n in micrometric and nanometric sizes with same structure and composition. Interestingly, both materials show similar reversible thermo- and pressure-luminescent response as well as reversible electrical response to volatile organic solvents such as acetic acid. X-ray diffraction studies under different conditions, temperatures and pressures, in combination with theoretical calculations allow rationalizing the physical properties of this compound and its changes under physical stimuli. Thus, the emission dramatically increases when lowering the temperature, while an enhancement of the pressure produces a decrease in the emission intensity. These observations emerge as a direct consequence of the high structural flexibility of the Cu2I2 chains which undergo a contraction in Cu-Cu distances as far as temperature decreases or pressure increases. However, the strong structural changes observed under high pressure lead to an unexpected effect that produces a less effective Cu-Cu orbital overlapping that justifies the decrease in the intensity emission. This work shows the high potential of materials based on Cu2I2 chains for new applicationsThe authors thank financial support from the Spanish Ministerio de Economía y Competitividad (MAT2013-46502-C2-2P, MAT2016-77608-C3-1-P, MAT2016-75883-C2-2-P, MAT2010-20843-C02-01, MAT2016-75586-C4-4-P, CTQ2016-75816-C2-1P), also thank the scientific computing center (CCC) of the Autonoma University of Madrid for their time. J.I.M. acknowledges the financial support by the Ramón y Cajal Program of MINECO (Grant RYC-2015-17730) and the EU via the ERC-Synergy Program (Grant ERC-2013-SYG-610256 NANOCOSMOS

The regional green potential of the European innovation system

The brief provides an overview of green technological development across European regions employing the Economic Fitness Complexity approach to establish a green technology space. The study explores the associations between comparative advantage in specific technological domains and a region’s capacity to develop green technologies, i.e. its Green Fitness. Furthermore, it addresses the interaction between the green and non-green knowledge bases, with a particular focus on whether regional know-how in the non-green technological realm can be exploited in the green domain and vice versa. To this aim, a metric of regional Green Potential is proposed. The analysis suggests that regions specialised in green domains, irrespective of their complexity, have a higher propensity to develop technologies connected with green technologies. Green technologies are linked mostly to technologies related to the production or transformation of materials; with engines and pumps; and with construction methods. The regions with the highest Green Potential are not necessarily those with the highest Green Fitness. The results suggest that there is a potential for green and non-green technological advances to generate positive spillovers in terms of capabilities to produce innovations across the spectrum of technological complexity.JRC.B.7 - Knowledge for Finance, Innovation and Growt

Green innovation and income inequality: A complex system analysis.

The objective of this paper is to analyse the relationship between income inequality and environmental innovation. To this end, we use the Economic Fitness and Complexity algorithm to compute an index of green inventive capacity in a panel of 57 countries over the period 1970-2010. The empirical analysis reveals that, on average, inequality is detrimental to countries' capacity to develop complex green technologies. Using non-parametric methods we further articulate this general finding and uncover interesting non-linearities in the relationship between innovation and inequality. [Abstract copyright: © 2022 The Author(s).

Green innovation and income inequality: A complex system analysis.

The objective of this paper is to analyse the relationship between income inequality and environmental innovation. To this end, we use the Economic Fitness and Complexity algorithm to compute an index of green inventive capacity in a panel of 57 countries over the period 1970-2010. The empirical analysis reveals that, on average, inequality is detrimental to countries' capacity to develop complex green technologies. Using non-parametric methods we further articulate this general finding and uncover interesting non-linearities in the relationship between innovation and inequality. [Abstract copyright: © 2022 The Author(s).