Despite spectacular advances in conversion efficiency of perovskite solar cell many aspects its operating modes are still poorly understood. Capacitance constitutes a key parameter to explore which mechanisms control particular functioning and undesired effects as current hysteresis. Analyzing capacitive responses allows addressing not only the nature charge distribution device but also kinetics charging processes how they alter current. Two main polarization identified. Dielectric...

Capacitance response of perovskite-based solar cells (PSCs) can be exploited to infer underlying physical mechanisms, both in the materials bulk and at outer interfaces. Particularly interesting is applying depletion layer capacitance theory PSCs, following common procedures used with inorganic organic photovoltaic devices. Voltage-modulation width allows extracting relevant parameters as absorber defect density built-in potential by means Mott-Schottky (MS) analysis. However, uncritical use...

Hybrid lead halide perovskites have reached very large solar to electricity power conversion efficiencies, in some cases exceeding 20%. The most extensively used perovskite‐based cell configuration comprises CH 3 NH PbI (MAPbI ) combination with electron (TiO 2 and hole 2,2′,7,7′‐tetrakis( N , ‐di‐ p ‐methoxyphenylamine)‐9,9‐ spiro ‐bifluorene ( ‐OMeTAD) selective contacts. recognition that the performance is heavily affected by time scale of measurement preconditioning procedures has raised...

We investigate the ferroelectric properties of photovoltaic methylammonium lead halide CH3NH3PbI3 perovskite using piezoelectric force microscopy (PFM) and macroscopic polarization methods. The electric is clearly observed by amplitude phase hysteresis loops. However, loop decreases as frequency lowered, persisting for a short time only, in one second regime, indicating that does not exhibit permanent at room temperature. This result confirmed measurement based on standard capacitive method....

Abstract This microreview focuses on the preparation of homogeneous catalysts group 8–11 metals containing N‐heterocyclic carbene ligands. The current status design mono‐, bi‐ and tridentate NHC ligands is reviewed through description authors' own work. catalytic applications such complexes include hydrogen‐borrowing, C–C coupling, reduction double bonds C–H activation reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

The main objective of this review is to give a general overview the structure, electrochemistry (when available), and catalytic performance Ru complexes, which are capable oxidizing water molecular dioxygen, highlight their more relevant features. description catalysts mainly divided into complexes that contain Ru−O−Ru bridging group those do not. Finally few conclusions drawn from global all presented here, some guidelines for future catalyst design given.

The iridium complex [Cp*Ir(H2O)3](SO4) was used as an organometallic source for the electrodeposition of oxide onto Fe2O3. new iridium-containing electrode allowed us to study coupling between photocatalytic properties hematite and electrocatalytic iridium-based material. A cathodic shift photocurrent water oxidation upon observed, which increased with increasing surface concentration IrOx on highest tested amounts 300 mV at 200 μA·cm–2 current density. catalytic mechanism layer unveiled by...

We present the use of halide (PbCl₂) and non-halide lead precursors (Pb(OAc)₂(OAc = CH₃CH₂COO⁻), Pb(NO₃)₂, Pb(acac)₂(acac (CH₃COCHCOCH₃)⁻) PbCO₃) for preparation perovskite solar cells.

Power law voltage decay in perovskite solar cells shows cooperative relaxation phenomena.

Negative capacitance in the low-frequency domain and inverted hysteresis are familiar features perovskite solar cells, which origin is still under discussion. Here we use impedance spectroscopy to analyze these responses methylammonium lead bromide cells treated with lithium cations at electron-selective layer/perovskite interface iodide devices exposed different relative humidity conditions. Employing surface polarization model, obtain a time constant associated kinetics of interaction...

Abstract A series of new bridging, chelating and pincer N ‐heterocyclic carbenes Rh I III have been obtained under mild conditions. The compounds fully characterised their crystal structures determined. chelate‐pincer coordination the ligands means that stability these is significantly greater than other carbene complexes Rh. tested in catalytic reactions such as hydrogen transfer from alcohols to ketones, hydrosilylation terminal olefins alkynes; they show a high activity for both...

Three different reaction procedures for the coordination of N-n-butyl-N'-(2-pyridylmethyl)imidazolium salt have produced new N-heterocyclic complexes Rh and Ir. The direct imidazolium with [IrCl(cod)](2) provides a NHC-Ir(III)-H complex, while transmetalation from silver-NHC complex deprotonation NEt(3) give NHC M(I) M(III) when reacting [MCl(cod)](2) or [MCl(coe)(2)](2) (M = Rh, Ir). crystal structures biscarbene Rh(III) Ir(III) are described. catalytic properties compounds obtained been...

Double trouble: A series of complexes rhodium and iridium has been obtained with a triazolediylidene ligand, which behaves as an extraordinarily versatile Janus-type ligand to form dinuclear complexes. The showed improved catalytic properties over their mononuclear counterparts. picture shows diiridium complex 1,2,4-trimethyltriazole-3,5-diylidene (Ir gray, C white, N blue, O red, Cl green).

Abstract Interest in the electrochemical reduction of organic compounds as an alternative to hydrogen electrosynthesis is driven, among other reasons, by fact that products obtained this process may have more economic value than H 2 . Furthermore, technique, coupled with renewable sources electricity, open door for large volume green chemical synthesis. In present article, and hydrogenation nitrobenzene aniline at neutral pH focused upon, using copper electrodes without palladium decoration....

A ferrocenyl–imidazolium salt can be employed as a precursor to stable [IrIII(H)(biscarbene)] complex (see X-ray crystal structure) under very mild conditions. The study shows that the role of base in activation imidazolium may not just simple deprotonation precursor.

A new bis(imidazolylidene) tripodal ligand has been obtained by a simple method. The coordination of this to Rh provides the first Rh(III) complex with bis(carbene) in coordination, and its catalytic properties toward hydrogen transfer have examined.

The preparation of a new bis(dichloroimidazolylidene) ligand has provided chelate-N-heterocyclic complexes Rh(I) and Ir(I), which have been fully characterized. crystal structures three the are described. study electronic properties ligands was made on basis ν(CO) stretching frequencies carbonyl derivatives, showing that chloroimidazolylidene is significantly less σ-donating than related nonchlorinated analogue. This modification important implications for catalytic compounds obtained, as...

Two tripodal trisimidazolium ligand precursors have been tested in the synthesis of new N-heterocyclic carbene rhodium and iridium complexes. [Tris(3-methylbenzimidazolium-1-yl)]methane sulfate gave products with coordination decomposed precursor. [1,1,1-Tris(3-butylimidazolium-1-yl)methyl]ethane trichloride (TIMEH(3)(Bu)) coordinated to metal a chelate bridged-chelate form, depending on reaction conditions. The crystal structures two are described. compounds resulting from TIME(Bu) were...

The carbene-ligand precursors methylenebis(N-alkylimidazolium) iodide (alkyl = methyl, neo-pentyl) and ethylenebis(N-methylimidazolium) chloride have been used in the preparation of several new Ru(II)-p-cymene complexes where ligand behaves as mono- bidentate. molecular structures two biscarbene-complexes are reported. From data reported, we can conclude that steric reasons (mainly bisimidazolium linkers, methylene/ethylene) main factors determining both reactivity synthetic difficulties products

A new iridium complex, IrCp*Cl(PyPyz)[TFSI], has been synthesized and used as additive for the hole transporter material, spiro-OMeTAD, in perovskite solar cells. The cells prepared with this Ir present higher efficiency than reference cells, similar to Co additive. We have determined that presence of metal complexes additives decreases recombination rate, it observed by impedance spectroscopy. Very interestingly, while after 3 months 22% 70% cell additive, respectively, devices containing...

Structure, morphology and concentration of defects in hybrid perovskites depend on the type substrate used for film growth.

Small cation size along with removal of trace iron from the electrolyte solution enables practical use earth-abundant nickel oxide electrodes for selective oxidation organic molecules over water in aqueous solutions.

A new pyridine-4,5-dichloroimidazol-2-ylidene complex of Ir(I) has been obtained, and its catalytic activity toward hydrosilylation phenylacetylene 4-aminophenylacetylene studied. The addition HSiMe2Ph to the latter species afforded corresponding IrIII-NHC hydrosilylated species, whose molecular structure was determined. This nonchlorinated analogue have used as catalyst a series reactions designed for elucidating processes. mechanism studied by means electrospray ionization mass...