Search results for "Triiodide"

Injection and ultrafast regeneration in dye-sensitized solar cells

2014

Injection of an electron from the excited dye molecule to the semiconductor is the initial charge separation step in dye-sensitized solar cells (DSC's). Though the dynamics of the forward injection process has been widely studied, the results reported so far are controversial, especially for complete DSC's. In this work, the electron injection in titanium dioxide (TiO2) films sensitized with ruthenium bipyridyl dyes N3 and N719 was studied both in neat solvent and in a typical iodide/triiodide (I-/I3 -) DSC electrolyte. Transient absorption (TA) spectroscopy was used to monitor both the formation of the oxidized dye and the arrival of injected electrons to the conduction band of TiO2. Emiss…

Gel Electrophoresis Coupled to Inductively Coupled Plasma−Mass Spectrometry Using Species-Specific Isotope Dilution for Iodide and Iodate Determinati…

2007

In this paper, we present an online coupling of gel electrophoresis (GE) and inductively coupled plasma-mass spectrometry (ICP-MS) for the determination of iodine species (iodide and iodate) in liquid (seawater) and aerosol samples. For the first time, this approach is applied to the analysis of small molecules, and initial systematic investigations revealed that the migration behavior as well as the detection sensitivity strongly depends on the matrix (e.g., high concentrations of chloride). These effects could consequently affect the accuracy of analytical results, so that they need to be considered for the analysis of real samples. The technique used for quantification is species-specifi…

Flow injection biamperometric determination of chloramphenicol and related nitro compounds by on-line chemical photodegradation

2000

Abstract An unsegmented continuous-flow assembly for the determination of chloramphenicol is proposed. The determination is based on the on-line photodegradation of the drug in an NH4+/NH3 buffer at pH 10.4 by using a photoreactor consisting of a 697 cm long × 0.8 mm ID piece of PTFE tubing coiled around an 8 W low-pressure mercury lamp. Photodegraded chloramphenicol is detected by photolytic cleavage of nitrite from the parent compound as well as by organic oxidizing photofragments, and their subsequent reaction with iodide ion, which is monitored biamperometrically. Triiodide thus formed is detected in excess iodide solution by polarizing two platinum electrodes at 100 mV. The calibration…

Crystal structure of 1,10-phenanthrolindiium bis(triiodide) monohydrate, C12H12I6N2O

2014

Room-Temperature Cubic Phase Crystallization and High Stability of Vacuum-Deposited Methylammonium Lead Triiodide Thin Films for High-Efficiency Sola…

2019

Methylammonium lead triiodide (MAPI) has emerged as a high-performance photovoltaic material. Common understanding is that at room temperature it adopts a tetragonal phase and it only converts to the perfect cubic phase around 50-60 ºC. Most MAPI films are prepared using a solution-based coating process, yet they can also be obtained by vapor phase deposition methods. Vapor phase processed MAPI films have significantly different characteristics compared to their solvent processed analogous, such as a relatively small crystal grain sizes and short excited state lifetimes. Yet solar cells based on vapor phase processed MAPI films exhibit high power conversion efficiencies. Surprisingly, after…

Low Temperature, Vacuum-Processed Bismuth Triiodide Solar Cells with Organic Small-Molecule Hole Transport Bilayer

2021

Herein, the preparation of fully vacuum-processed bismuth triiodide solar cells with low annealing temperature is reported. Planar n-i-p devices are prepared using a thin compact SnO2 layer as the electron extraction layer and an electron blocking/hole extraction bilayer consisting of an intrinsic and doped organic hole-transport molecule. Using this configuration, herein, higher fill-factors and overall power conversion efficiencies than with conventional solution-processed hole transport materials are achieved.

Investigation of recovery mechanisms in dye sensitized solar cells

2016

Abstract We study the spontaneous recovery phenomenon displayed by solar cells sensitized with a ruthenium complex-based dye N719, which manifests with the increase over the time (from several minutes up to some days) of the short circuit current density J sc and the open circuit voltage V oc , during cell illumination. Under dark conditions the current decreases over time after the application of forward bias voltages. We investigate the effects of temperature and electrolyte composition by means of current–voltage measurements and electrochemical impedance spectroscopy, both under dark and illumination conditions. The main result is that the recovery of the performances depends on the cha…

Anion–π Interactions in Salts with Polyhalide Anions: Trapping of I 4 2−

2010

The directionality of interaction of electron-deficient π systems with spherical anions (e.g,. halides) can be controlled by secondary effects like NH or CH hydrogen bonding. In this study a series of pentafluorophenyl-substituted salts with polyhalide anions is investigated. The compounds are obtained by aerobic oxidation of the corresponding halide upon crystallization. Solid-state structures reveal that in bromide 2, directing NH-anion interactions position the bromide ion in an η(1)-type fashion over but not in the center of the aromatic ring. The same directing forces are effective in corresponding tribromide salt 3. In the crystal, the bromide ion is paneled by four electron-deficient…

Tetramethyl-Bis(ethylenedithio)-Tetrathiafulvalene (TM-BEDT-TTF) Revisited: Crystal Structures, Chiroptical Properties, Theoretical Calculations, and…

2013

The (S,S,S,S) and (R,R,R,R) enantiomers of tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) show equatorial conformation for the four methyl groups in the solid state, according to the single-crystal X-ray analyses. Theoretical calculations at the Density Functional Theory (DFT) and time-dependent (TD) DFT levels indicate higher gas phase stability for the axial conformer than the equatorial one by 1.25kcal center dot mole-1 and allow the assignment of the UV-vis and circular dichroism transitions. A complete series of radical cation salts of 1:1 stoichiometry with the triiodide anion I3- was obtained by electrocrystallization of both enantiopure and racemic forms of the don…

CCDC 1403476: Experimental Crystal Structure Determination

2015

Related Article: Maciej Bujak, Walter Frank|2014|Z.Kristallogr.-New Cryst.Struct.|229|379|doi:10.1515/ncrs-2014-0199