0000000000180354
AUTHOR
Filippo De Angelis
Computational modeling of single-versus double-anchoring modes in di-branched organic sensitizers on TiO2 surfaces: structural and electronic properties
We present a first-principles DFT investigation of the adsorption geometry on the anatase (101) surface of a prototypical di-branched organic dye based on the extended tetrathiafulvalene moiety, incorporating two anchoring cyanoacrylic acid units. Reduced model systems with one and two anchoring groups have been initially studied to investigate the vibrational frequencies related to TiO2 dye adsorption. Our calculations confirm that the reduced systems can be used as reliable models to study the anchoring modes and that the conclusions extracted from the reduced systems can be extrapolated to the entire molecule. A series of molecular structures have been investigated to simulate the anchor…
White-light phosphorescence emission from a single molecule: application to OLED.
A simple mononuclear cyclometallated iridium(III) complex exhibits white photo- and electro- luminescence in the wavelength range from 440 to 800 nm, which originates from a single emitting excited state of mixed character. Bolink Henk, Henk.Bolink@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es
Light-Induced Formation of Pb3+Paramagnetic Species in Lead Halide Perovskites
Hybrid halide perovskites are soft materials processed at room temperature, revolutionary players in the photovoltaic field. Nowadays, investigation of the nature and role of defects is seen as one of the key challenges toward full comprehension of their behavior and achievement of high device stability under working conditions. We reveal the reversible generation, under illumination, of paramagnetic Pb3+ defects in CH3NH3PbI3, synthesized in ambient conditions, induced by the presence of Pb-O defects in the perovskite structure that may trap photogenerated holes, possibly mediated by the concomitant oxidation and migration of ions. According to the mechanism that we hypothesize, one charge…
An inconvenient influence of iridium(III) isomer on OLED efficiency.
The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact pe…