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The long-standing debate about the morphology of colloidal methylammonium lead bromide perovskites nanocrystals, manufactured by our nontemplate synthetic strategy reported in 2014, is now resolved; specifically, the highest green emissive single nanoplatelets (of up to 93%) with long-term chemical and photochemical stability have been obtained after suitable purification steps., We thank MICINN (CTQ2017-82711-P, PID2020-115710GB-100/AEI/10.13039/501100011033), MINECO (MMU Unit of Excellence “Maria de Maeztu” CEX2019-000919-M) and Generalitat Valenciana (PROMETEO/2019/080 and IDIFEDER/2018/064), all of them partially co-financed with FEDER funds. I. R-P. acknowledges the support from Spanish Ministry of Science, Innovation and Universities (FPU17/05564). L. P. acknowledges the support from MINECO through Ramón y Cajal grant (RYC2018-026103-I) and the Spanish State Research Agency (Grant No. PID2020-117371RA-I00), from the Xunta de Galicia (ED431F2021/05). The HRSTEM measurements were performed in the Laboratorio de Microscopias Avanzadas (LMA) at the Universidad de Zaragoza (Spain). R. A. acknowledges funding from the Spanish MICINN (project grant PID2019-104739GB-100/AEI/10.13039/501100011033), the Government of Aragon (project DGA E13- 20R) and European Union H2020 program “ESTEEM3” (823717).

Photophysical characterization of upconversion nanoparticles (UCNPs) and nanohybrids (UCNHs) is more challenging than that of down-conversion nanomaterials. Moreover, it is still difficult to gain knowledge about the homogeneity of the sample and colocalization of emissive chromophores and nanoparticles in nanohybrids. Near infrared laser scanning microscopy (NIR-LSM) is a well-known and useful imaging technique, which enables excitation in the NIR region and has been extensively applied to optical fluorescence imaging of organic fluorophores and nanomaterials, such as quantum dots, which exhibit a short-lived emission. NIR-LSM has recently been used to determine the empirical emission lifetime of UCNPs, thus extending its application range to nanomaterials with a long lifetime emission. Here, we review our previous findings and include new measurements and samples to fully address the potential of this technique. NIR-LSM has proved to be extraordinarily useful not only for photophysical characterization of UCNHs consisting of UCNPs capped with a fluorophore to easily visualize the occurrence of the resonance energy transfer process between the UCNH constituents and their homogeneity, but also to assess the colocalization of the fluorophore and the UCNP in the UCNH; all this information can be acquired on the micro-/nano-meter scale by just taking one image.

We demonstrate here the suitability of CsPbBr3nanoparticles as photosensitizers for a demanding photoredox catalytic homo- and cross-coupling of alkyl bromides at room temperature by merely using visible light and an electron donor, thanks to the cooperative action between the nanoparticle surface and organic capping. Fil: Rosa-Pardo, Ignacio. Instituto de Ciencia Molecular; España. Universidad de Valencia; España Fil: Casadevall, Carla. Barcelona Institute Of Science And Technology. Institut Català D'investigació Química.; España Fil: Schmidt, Luciana Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: Castro Claros, José Miguel. Barcelona Institute Of Science And Technology. Institut Català D'investigació Química.; España Fil: Galian Baca, Raquel Eugenia. Instituto de Ciencia Molecular; España. Universidad de Valencia; España Fil: Lloret-Fillol, Julio. Barcelona Institute Of Science And Technology. Institut Català D'investigació Química.; España Fil: Pérez-Prieto, Julia. Instituto de Ciencia Molecular; España. Universidad de Valencia; España

A novel biocompatible nanohybrid consisting of gold nanoclusters (AuNCs) capped with FAD cofactor molecules exhibits distinctive and unique features compared to those of free FAD. The spherical shape of the AuNC provides a large surface to volume ratio, thereby enabling a huge amount of FAD on the AuNC surface while, in basic media and under nitrogen atmosphere, the considerable curvature of its surface enables light-triggered delivery of lumichrome, which is an effective photosensitizer and fluorescent probe.

Ruddlesden-Popper lead halide perovskite (RP-LHP) nano-nanostructures can be regarded as self-assembled quantum wells or superlattices of 3D perovskites with an intrinsic quantum well thickness of a single or a few (n=2-4) lead halide layers; the quantum wells are separated by organic layers. They can be scaled down to a single quantum well dimension. Here, the preparation of highly (photo)chemical and colloidal stable hybrid LHP nanosheets (NSs) of ca. 7.4 μm lateral size and 2.5 nm quantum well height (thereby presenting a deep blue emission at ca. 440 nm), is reported for the first time. The NSs are close-lying and they even interconnect when deposited on a substrate. Their synthesis is based on the use of the p-toluenesulfonic acid/dodecylamine (pTS/DDA) ligand pair and their (photo)chemical stability and photoluminescence is enhanced by adding EuBr2 nanodots (EuNDs). Strikingly, they can be preserved as a solid and stored for at least one year. The blue emissive colloid can be recovered from the solid as needed by simply dispersing the powder in toluene and then using it to prepare solid films, making them very promising candidates for manufacturing devices., The work was supported by the Spanish MICINN (CTQ2017-82711-P, PID2020-115710GB-100/AEI/10.13039/501100011033, FPU17/ 05564 (IRP), partially co-financed with FEDER funds, PID2019-111742GA-100, PID2019-104739GB-100/AEI/10.13039/501100011033, and the “Maria de Maeztu” Programme for Units of Excellence in R&D (CEX2019-000919-M)) and the European Union (ERC-2018-StG 804110-2D-PnitoChem to G.A., “ESTEEM3” (823717) and Graphene Flagship (881603) to R.A.). The authors also thank the financial support by Generalitat Valenciana (PROMETEO/2019/080 and IDIFEDER/2018/064 to J.P.P., Santiago Grisolía (RCT), CIDEGENT/2018/001 and IDIFEDER/2018/061 co-financed by FEDER to G.A.), the Government of Aragon (project DGA E13-20R) and the Deutsche Forschungsgemeinschaft (DFG, FLAG-ERA AB694/2-1 to G.A.). EDS-STEM analyses have been performed at the Laboratorio de Microscopias Avanzadas, Universidad de Zaragoza, Spain. V.O. is an ALN fellow.

Nanoparticles for medical use should be non-cytotoxic and free of bacterial contamination. Upconversion nanoparticles (UCNPs) coated with cucurbit[7]uril (CB[7]) made by combining UCNPs free of oleic acid, here termed bare UCNPs (UCn), and CB[7], i.e., UC@CB[7] nanohybrids, could be used as photoactive inorganic-organic hybrid scaffolds for biological applications. UCNPs, in general, are not considered to be highly toxic materials, but the release of fluorides and lanthanides upon their dissolution may cause cytotoxicity. To identify potential adverse effects of the nanoparticles, dehydrogenase activity of endothelial cells, exposed to various concentrations of the UCNPs, was determined. Data were verified by measuring lactate dehydrogenase release as the indicator of loss of plasma membrane integrity, which indicates necrotic cell death. This assay, in combination with calcein AM/Ethidium homodimer-1 staining, identified induction of apoptosis as main mode of cell death for both particles. The data showed that the UCNPs are not cytotoxic to endothelial cells, and the samples did not contain endotoxin contamination. Higher cytotoxicity, however, was seen in HeLa and RAW 264.7 cells. This may be explained by differences in lysosome content and particle uptake rate. Internalization of UCn and UC@CB[7] nanohybrids by cells was demonstrated by NIR laser scanning microscopy.

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research. Ministerio de Ciencia e Innovación | Ref. RYC2018-026103-I Agencia Estatal de Investigación | Ref. CTQ2017-82711-P Ministerio de Economía y Competitividad | Ref. MDM-2015-0538 Agencia Estatal de Investigación | Ref. PID2019-107314RB-I00

We demonstrate here the suitability of CsPbBr

This chapter discusses the key characteristics of the class of materials, liquid crystal phases, and a selection of emissive nanomaterials. Shape anisotropy of liquid crystal molecules and the aggregates results in birefringence due to the existence of two indices of refraction according to the directions of propagation and polarization of the light and according to the molecular orientation. Depending on the nature of the liquid crystal molecules, rod-like liquid crystals possess either a permanent or an induced dipole. In the presence of an applied electric field, the charged parts undergo opposing forces, proportional to their charge and to the field, which cause a molecular rotation until the dipole is aligned parallel to the field. Liquid crystal nanoscience has evolved into two major research thrusts. In one, liquid crystals are used either as templates for the syntheses of nanomaterials or they are used as organizing anisotropic fluids to assemble and manipulate nanoscale materials.

This chapter covers the photochemistry of oxygen containing groups reported in the 2018 to the mid-2020 period. It is mostly organized according to reaction types (Norrish type I, photo-Fries, etc.), but some sections focus on the particular functionality of several groups, such as photocaging, or the ability to carry out several chemical reactions in a single reaction vessel (photochemical reaction orthogonality). Applications of the photoreactions to the synthesis of relevant products, as well as to technology, are included. Mechanistic information available via steady-state and time-resolved studies, as well as the information derived from theoretical calculations, are briefly commented on. Consistent with the target of chapters from previous years, only photoreactions where oxygen-containing compounds are light-absorbing species, are addressed.

Upconversion nanoparticles (UCNPs) and dyes are combined to make nanohybrid systems, which take advantage of the synergic relationship between lanthanide (Ln)-based UCNPs and dyes. Ln-UCNPs are inorganic nanophosphors which absorb NIR light and emit narrow emission bands in the UV-NIR region with long luminescence lifetimes. These unique properties, when coordinated properly with dyes of the appropriate photophysical features, produce nanosystems with new photophysical properties. In this context, the UCNP-dye nanohybrids are very promising for potential sensing (ions and biomolecules) and theragnosis (imaging and therapy, e.g. photodynamic therapy).

Theranostic upconversion nanoparticles (UCNPs) are ideal candidates for personalized medicine. We present a smart, easy-to-prepare nanohybrid (NH) suitable for NIR-theragnosis and imaging tracking without triggering therapy simultaneously. The photophysical features of each component have been carefully selected in order to maximize the capabilities for theragnosis, in particular, the upconversion emission and the photosensitizer absorption. In addition, NH presents a fluorescent marker with one-photon absorption in the green and two-photon absorption cross-section at NIR wavelengths where the UCNP does not absorb, thus enabling innocuous tracking. Thus, the NH consists of NaYF4:Yb, Er, Tm (UCYbErTm) emitting in the UV, vis, and NIR; a broadband-absorbing natural porphyrin (PP) in the UV-to-NIR range but from 580 to 675 nm; and a 1,8-naphthalimide (NI) with two absorption bands (UV, VIS), and dual emission. In vitro assays demonstrate that UCYbErTm@PP/NI NH is noncytotoxic and extremely effective for NIR-...

The preparation of densely-packed films from hybrid lead halide perovskite nanocrystals is not trivial, as during assembly into the solid state both the charge transport and photoluminescence can be substantially altered. The objective of the present study was to retain the pre-engineered confined morphologies of hybrid lead halide perovskite nanocrystals in densely-packed solid films by using short organic ligands. Therefore, the roles of the organic ligands would be to provide stable colloids and a good passivation of the nanoparticle surface, as well as to enable the efficient assembly of the nanoparticles in the solid state. We report here an effective and reproducible process to deposit lead halide perovskite nanoparticle films from colloidal CH3NH3PbBr3 nanoparticles short organic ligands. Remarkably, we demonstrate that nanoparticle solid films with thicknesses of hundreds of nanometres can retain high photoluminescence, with a quantum yield of 80%, and still sustain charge transport.

Up to now, most strategies to build efficient 800 nm-light responsive upconversion nanoparticles (UCNPs) have included onion-layered structures, in which Nd3+ is confined within the inorganic crystal structure of at least one layer. We report here an easy room-temperature modular preparation of core-shell UCNPs consisting of NaYF4:Yb,Er(Tm)/NaYF4 (UCCS) with Nd3+ anchored at the organic capping by using cucurbituril[7] (CB[7]) as an adhesive. Strikingly, excitation at 800 nm effectively triggers the upconversion emission of UCCS@CB[7]@Nd nanohybrids.

The mechanism responsible for the extremely long photoluminescence (PL) lifetimes observed in many lead halide perovskites is still under debate. While the presence of trap states is widely accepted, the process of electron detrapping back to the emissive state has been mostly ignored, especially from deep traps as these are typically associated with nonradiative recombination. Here, we study the photophysics of methylammonium lead bromide perovskite nanocrystals (PNCs) with a photoluminescence quantum yield close to unity. We show that the lifetime of the spontaneous radiative recombination in PNCs is as short as 2 ns, which is expected considering the direct bandgap character of perovskites. All longer (up to microseconds) PL decay components result from the rapid reversible processes of multiple trapping and detrapping of carriers with a slow release of the excitation energy through the spontaneous emission channel. As our modeling shows, the trap (dark) and excitonic states are coupled by the trapping...

Heterogeneous catalysts that can absorb light over the solar range are ideal for green photocatalysis. Recently, attention has been directed towards the generation of novel solar-light photocatalysts, in particular, metal-free polymers. Herein, it is demonstrated that a metal-free, nonconjugated, anthraquinone-based copolymer (poly[1,4-diamine-9,10-dioxoanthracene-alt-(benzene-1,4-dioic acid)] (COP)) with a strong absorption in the visible region is effective as a sunlight heterogeneous photocatalyst. As a proof of concept, it has been used to mineralize 2,5-dichlorophenol (2,5-DCP) in water under air and sunlight irradiation. The photocatalytic efficiency of COP compares well with that of TiO2 -P25 when the reaction is carried out in a solar photoreactor in acid medium. Steady-state and time-resolved (absorption and emission) studies performed on COP suspended in 6:4 DMF/H2 O have provided valuable information about the COP species generated under different pH conditions. Steady-state absorption and fluorescence data are consistent with the existence of a tautomeric equilibrium between the 9,10-keto and 1,10-iminoketo quinoid forms for the anthraquinone in the ground state. Moreover, in basic media, transient absorption measurements showed the presence of two bands ascribed to the tautomeric triplet excited states, whereas only one of the triplets was observed in acid medium. A mechanism for the photocatalyzed degradation of 2,5-DCP by COP is proposed on the basis of these observations.

To prepare water-dispersible, biocompatible, ratiometric pH nanosensors is challenging. We report here for the first time that the emission colour of NAD+-capped AuNCs responds to the mono-/bidentate anchoring of the phosphoric groups of the ligand. The AuNCs exhibit a high luminescence (21% quantum yield) and an outstanding performance as fluorescent ratiometric pH sensors over a broad pH range.

International audience; The Conference and Spring School on Properties, Design and Applications of Upconversion Nanomaterials (UPCON) provides a new forum for all experts and newcomers in the field of upconversion research. On the occasion of the second UPCON 2018 in Valencia (Spain), we are pleased to present a collection of 12 reviews and research articles that reflect recent advances in upconversion materials, their unique luminescent properties and many applications spanning from nanoscale thermometry to biomedicine.

Mixing precursors of lead(ii) polymers with those of lead bromide-based nanoparticles (CH3NH3PbBr3 perovskites or PbBr2), at room temperature and in the presence of cyclohexanemethylammonium bromide, generated colloidal nanocomposites which, when deposited on a hydrophobic surface led to long, one-dimensional, ordered and well-defined architectures. ispartof: CHEMICAL COMMUNICATIONS vol:55 issue:20 pages:2968-2971 ispartof: location:England status: published

Correction for ‘NIR laser scanning microscopy for photophysical characterization of upconversion nanoparticles and nanohybrids’ by Juan Ferrera-González et al., Nanoscale, 2021, 13, 10067–10080, DOI: 10.1039/D1NR00389E.

CH3 NH3 PbBr3 perovskite nanoparticles (PAD ) are prepared with a photoluminescence quantum yield of ≈100% in air atmosphere by using the quasi-spherical shaped 2-adamantylammonium bromide (ADBr) as the only capping ligand. The photostability under wet conditions of this kind of nanoparticles is enhanced by using cucurbit[7]uril-adamantylammonium (AD@CB) host-guest complexes as the capping ligand.

Upconversion-perovskite nanohybrids are prepared by assembling CH3NH3PbBr3 perovskite nanoparticles (PK) with naked NaYF4:Yb3+,Tm3+ nanoparticles (UCn) via an innovative strategy consisting of using cucurbit[7]uril (CB[7]) to anchor the perovskite nanoparticles firmly and closely to the upconversion nanoparticles, thus leading to UCn@PKCB nanohybrids. A commercial multiphoton laser scanning confocal microscope is used to demonstrate the successful assembly. This technique proves to be useful to evaluate luminescence lifetime in the range of several tens of μs and allows visualization of the extraordinarily efficient nontrivial resonance energy transfer from the upconversion nanoparticle to the perovskite after near-infrared (NIR) excitation of the nanohybrid as well as the homogeneity of the UCn@PKCB sample. The considerable photostability of the perovskite in these nanohybrids is demonstrated by prolonged irradiation of the nanohybrid under UV light as well as under NIR light.

Sensitized emission of lead halide perovskite nanoparticles (LHPNPs) can be achieved by near‐infrared (NIR) excitation of nearby lanthanide‐doped upconversion nanoparticles (UCNPs) by using a low‐cost diode laser. Here, the first preparation of linear assemblies of core and core–shell NPs, as well as linear coassemblies of LHPNPs and UCNPs, within an open peapod‐like lead sulfate shell are reported. UCNPs with a NaYF4 matrix doped with ytterbium and thulium or erbium, and with an inert shell of NaYF4 in the case of core‐shell, and all‐inorganic CsPbX3 NPs (X = halide) are chosen for these studies. Interestingly, the lead sulfate shell enhances the luminescence of the core/core– shell UCNPs in the polymers by ≈20‐fold and it also plays a role in the efficiency of the sensitized emission of the LHPNPs under NIR excitation of the UCNP‐LHPNP copolymers, as well as in the chemical stability of the LHPNPs in contact with water. The (co)polymers are prepared as colloids and deposited as solid films on a glass substrate. The lifetime of the sensitized LHP emission and the efficiency of the process wholly depends on the irradiance and on the sample state. These copolymers are promising candidates for the manufacture of photonic devices.

Nanoparticles possess distinctive properties compared to those of their bulk counterparts. They can be prepared as colloids using molecules which play a key role in their preparation, colloidal stability, functionality, and/or optical features. These molecules can act as solvents, surfactants, reactants and ligands. Photoactive nanoparticles exhibit unique optical features due to the combined effect of their nanometric scale and the derived quantum confinement effect. The degree and type of response to size is related to their composition. They can form either colourless or colourful colloids, emit light either at longer wavelengths than those of the absorbed light (down-conversion luminescence) or at shorter wavelengths (up-conversion luminescence). In addition, the nanostructures can exhibit enhanced properties compared with their bulk counterparts, (for example, superior chemical sensing) due to their intrinsic large surface/volume ratio and their functionality can be further enhanced by ligand exchange or modification. Moreover, the processability of colloidal nanoparticles is crucial to many of their applications, such as for light-emitting devices and in optoelectronics, among other applications.

[EN] A Web page has been designed by master students in order to engage them in collaborative and cooperative learning, thus improving their learning and comprehension of relevant concepts and topics. To that purpose, topics included in the subject Advanced Techniques in Chemistry which is part of the Master in Sustainable Chemistry of the University of Valencia have been included in the Webpage with the help of WIX software. This approach makes intensive use of the Web as a key technological resource for learning, where the information seen in the subject is summarized and given in an applicative and pertinent context that is easy to understand for all public interested in the topics discussed in there. This tool allows the development of a key digital competence in the Spanish educational system, articulating the development of the Website with the management of multimedia content. It also allows a sense of initiative and entrepreneurship, since it is of total freedom on the part of the students working in group, the uploaded content, always following the knowledge developed and acquired in the subject., [ES] Se ha diseñado una página web para involucrar a los estudiantes de máster en el aprendizaje colaborativo y cooperativo, mejorando así su aprendizaje y comprensión de los temas y conceptos relevantes. Para ello, los temas incluidos en la asignatura Técnicas Avanzadas en Química que forma parte del Máster en Química Sostenible de la Universidad de Valencia se han incluido en la página web con la ayuda del software WIX. Este enfoque hace un uso intensivo de la web como recurso tecnológico clave de aprendizaje, donde se resume la información vista en la asignatura y se le da un contexto aplicativo y pertinente fácil de entender para todo el público interesado en los temas allí tratados. Esta herramienta permite el desarrollo de una competencia digital clave en el sistema educativo español, articulando el desarrollo de la página web con el manejo de contenido multimedia. Además permite un sentido de iniciativa y emprendimiento, ya que hay libertad por parte de los estudiantes trabajando en grupo, para sellecionar el contenido de la página, siempre siguiendo el conocimiento desarrollado y adquirido en la asignatura y el asesoramiento de la profesora.

Up to now, most strategies to build efficient 800 nm-light responsive upconversion nanoparticles (UCNPs) have included onion-layered structures, in which Nd3+ is confined within the inorganic crystal structure of at least one layer. We report here an easy room-temperature modular preparation of core-shell UCNPs consisting of NaYF4:Yb,Er(Tm)/NaYF4 (UCCS) with Nd3+ anchored at the organic capping by using cucurbituril[7] (CB[7]) as an adhesive. Strikingly, excitation at 800 nm effectively triggers the upconversion emission of UCCS@CB[7]@Nd nanohybrids.

A novel preparation of lead halide, CH3NH3PbBr3, perovskite nanoparticle solid films from colloidal "naked" nanoparticles, that is, dispersible nanoparticles without any surfactant, is reported. The colloids are obtained by simply adding potassium ions, whose counterions are both more lipophilic and less coordinating than bromide ions, to the perovskite precursor solutions (CH3NH3Br/PbBr2 in dimethylformamide) following the reprecipitation strategy. The naked nanoparticles exhibit a low tendency to aggregate in solution, and they effectively self-assembled on a substrate by centrifugation of the colloid, leading to homogeneous nanoparticle solid films with arbitrary thickness. These results are expected to spur further the interest in lead halide perovskites due to the new opportunities offered by these films. Fil: Gonzalez-Carrero, Soranyel. Instituto de Ciencia Molecular; España. Universidad de Valencia; España Fil: Schmidt, Luciana Carina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: Rosa-Pardo, Ignacio. Instituto de Ciencia Molecular; España. Universidad de Valencia; España Fil: Martínez-Sarti, Laura. Instituto de Ciencia Molecular; España. Universidad de Valencia; España Fil: Sessolo, Michele. Instituto de Ciencia Molecular; España. Universidad de Valencia; España Fil: Galian, Raquel E.. Universidad de Valencia; España. Instituto de Ciencia Molecular; España Fil: Perez Prieto, Julia. Instituto de Ciencia Molecular; España. Universidad de Valencia; España

A new family of cobalt complexes with the general formula [CoII(OTf)2(Y,XPyMetacn)] (1R,Y,XPyMetacn ¼ 1-[(4-X-3,5-Y-2-pyridyl)methyl]-4,7-dimethyl-1,4,7-triazacyclononane, (X ¼ CN (1CN), CO2Et (1CO2Et), Cl (1Cl), H(1H), NMe2 (1NMe2)) where (Y ¼ H, and X ¼ OMe when Y ¼ Me (1DMM)) is reported. We found that the electronic tuning of the Y,XPyMetacn ligand not only has an impact on the electronic and structural properties of the metal center, but also allows for a systematic water-reduction-catalytic control. In particular, the increase of the electron-withdrawing character of the pyridine moiety promotes a 20-fold enhancement of the catalytic outcome. By UV-Vis spectroscopy, luminescence quenching studies and Transient Absorption Spectroscopy (TAS), we have studied the direct reaction of the photogenerated [IrIII(ppy)2(bpyc )] (PSIr) species to form the elusive CoI intermediates. In particular, our attention is focused on the effect of the ligand architecture in this elemental step of the catalytic mechanism. Finally, kinetic isotopic experiments together with DFT calculations provide complementary information about the rate-determining step of the catalytic cycle We would like to thank the European Commission for the ERCCG-2014-648304 (J.Ll.-F) project. The financial support from ICIQ Foundation and CELLEX Foundation through the CELLEXICIQ high throughput experimentation platform and the Starting Career Program is gratefully acknowledged. We also thank CERCA Programme (Generalitat de Catalunya); The MINECO is acknowledged for a FPU fellowship to A.C (AP2012- 6436) and ICIQ-IPMP program (F.F.) and Severo Ochoa Excellence Accreditation 2014–2018 (SEV-2013-0319). J.M.L. is grateful for financial support from the Spanish MINECO CTQ2014-52525-P and the Catalan DIUE 2014SGR931. J.P-P. gratefully acknowledge CTQ2014-60174-P (partially co-financed with FEDER funds), Maria de Maeztu (MDM-2015-0538), RyC contract to MGB) and Fundación Ramón Areces for financial support

Organolead halide perovskites have emerged as exciting optoelectronic materials but a complete understanding of their photophysical properties is still lacking. Here, a morphological series of methylammonium lead bromide (MAPbBr 3 ) perovskites are studied by transient optical spectroscopies over eight orders of magnitude in timescale to investigate the effect of nanostructuring and surface states on the charge carrier dynamics. The sample preparation route and corresponding morphology changes influence the position of the optical features, recombination dynamics, excitation fluence dependence, and dramatically impact surface trap passivation. Growth of the perovskite layer in the presence of capping ligands or within mesoporous alumina increases the photoluminescence efficiency by multiple orders of magnitude, indicating that interfacing with metal oxides can lead to the passivation of surface nonradiative recombination centers. Nanoparticles (NPs) dispersed in solution show mixed behavior since they consist of NPs on nanoplatelets, while isolated NPs could be grown within mesoporous alumina with the addition of capping ligands. Investigation on the microsecond timescale suggests that an exponential distribution of states below the band edges results in long-lived charges. The investigations of the relationship between sample architecture and charge carrier dynamics will help in the appropriate choice of perovskite morphology for use in optoelectronic devices.

A generalization of the molar-ratio method is applied to the determination of the stoichiometry and apparent binding constant of metal nanoparticle-organic capping complexes (MmLx) using voltammetric data for the oxygen reduction reaction (ORR) in air-saturated aqueous phosphate buffer solutions. The method is applied to the formation of binary nanohybrids consisting of gold nanoparticles (AuNPs) capped with a rigid spacer, cucurbit[7]uril (CB), termed AuNP@CB, as well as to the formation of their ternary complexes (MmLxBz) with methylene blue (MB), termed AuNP@CB@MB. The obtained stoichiometries correspond to binding of four Au surface atoms for each CB unit.