Publications by Andrea Cannizzo

Tailoring p-Type Behavior in ZnO Quantum Dots through Enhanced Sol–Gel Synthesis: Mechanistic Insights into Zinc Vacancies

Jacques-Edouard Moser, Andrea Cannizzo, Etienne Christophe Socie, Camila Bacellar Cases Da Silveira, Victoria Kabanova

The synthesis and control of properties of p-type ZnO is crucial for a variety of optoelectronic and spintronic applications; however, it remains challenging due to the control of intrinsic midgap (defect) states. In this study, we demonstrate a synthetic ...

2024

Ultrafast carrier dynamics and insights in defect mechanism of p-type colloidal ZnO QDs

Jacques-Edouard Moser, Andrea Cannizzo, Etienne Christophe Socie, Camila Bacellar Cases Da Silveira, Victoria Kabanova

In this study, we place a strong emphasis on understanding the ultrafast dynamics of carrier recombination pathways in p-type ZnO, especially in the midgap region. Synthesizing and controlling the properties of p-type ZnO remains a pivotal yet challenging ...

SPIE2024

Taking a snapshot of the triplet excited state of an OLED organometallic luminophore using X-rays

Andrea Cannizzo, Martin Beck, Giulia Fulvia Mancini, Camila Bacellar Cases Da Silveira, Samuel Menzi, Victoria Kabanova

OLED technology beyond small or expensive devices requires light-emitters, luminophores, based on earth-abundant elements. Understanding and experimental verification of charge transfer in luminophores are needed for this development. An organometallic mul ...

Nature Publishing Group2020

Ultrafast Broadband Fluorescence Up-conversion Study of the Electronic Relaxation of Metalloporphyrins

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo

We present a systematic study of the ultrafast fluorescence with broadband detection and similar to 110 fs resolution of 5,10,15,20-tetraphenylporphin (TPP) and 2,3,7,8,12,13,17,18-oc-taethylporphin (OEP), with open 3d-shell metals. We also revisit the cas ...

AMER CHEMICAL SOC2019

Charge migration and charge transfer in molecular systems

Jacques-Edouard Moser, Majed Chergui, Joël Teuscher, Ursula Röthlisberger, Christopher Alexander Arrell, Andrea Cannizzo, Pablo Lopez Tarifa, Natalie Renuka Banerji, Elisa Liberatore

The transfer of charge at the molecular level plays a fundamental role in many areas of chemistry, physics, biology and materials science. Today, more than 60 years after the seminal work of R. A. Marcus, charge transfer is still a very active field of res ...

2017

Dual Luminescence, Interligand Decay, and Nonradiative Electronic Relaxation of Cyclometalated Iridium Complexes in Solution

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo, Mahsa Silatani, Enrico Pomarico

Femtosecond broadband photoluminescence studies are presented for Ir(ppy)(3) (Ir1), Ir(ppy)(2)(pic) (Ir2), Ir(ppy)(2)(bpy)(PF6) (Ir3), Ir(ppz)(3) (Ir4), and Ir(ppz)(2)dipy (Ir5) (where ppy = 2-phenylpyridine, pic = picolinate, bpy = 2,2'-bipyridine, ppz = ...

American Chemical Society2016

Ultrafast electronic and vibrational relaxations in mixed-ligand dithione-dithiolato Ni, Pd, and Pt complexes

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Ahmad Odeh

Ultrafast excited-state dynamics of planar Pt, Pd, and Ni dithione-dithiolato complexes were investigated by transient absorption spectroscopy on the femtosecond-picosecond timescale. All studied complexes show a common photobehaviour, although individual ...

Royal Society of Chemistry2014

Ultrafast Relaxation Dynamics of Osmium-Polypyridine Complexes in Solution

Mohammad Khaja Nazeeruddin, Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo

We present steady-state absorption and emission spectroscopy and femtosecond broadband photoluminescence up-conversion spectroscopy studies of the electronic relaxation of Os(dmbp)(3) (Os1) and Os(bpy)(2)(dpp) (Os2) in ethanol, where dmbp is 4,4'-dimethyl- ...

American Chemical Society2013

Real-time observation of the charge transfer to solvent dynamics

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo

Intermolecular electron-transfer reactions have a crucial role in biology, solution chemistry and electrochemistry. The first step of such reactions is the expulsion of the electron to the solvent, whose mechanism is determined by the structure and dynamic ...

Nature Publishing Group2013

Ultraviolet transient absorption, transient grating and photon echo studies of aqueous tryptophan

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo, Ahmad Ajdar Zadeh Oskouei, Cristina Consani

We compare UV transient grating (TG) experiments of aqueous tryptophan with transient absorption (TA) and fluorescence up-conversion measurements. The TG and TA signals show a bi-exponential rise with sub-ps and ps time constants, which are consistent with ...

Elsevier2013

Polychromatic femtosecond fluorescence studies of metal-polypyridine complexes in solution

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo, Ahmed Maher Fahmy El-Zohry

Femtosecond-resolved broadband fluorescence studies are reported for M(bpy)(3) (M = Fe, Ru), RuN3 and RuN719 complexes in solution. We investigated the pump wavelength dependence of the fluorescence of aqueous Fe(bpy)(3) and the solvent and li ...

2012

Energy transfer and relaxation mechanisms in Cytochrome c

Majed Chergui, Olivier Christian Bräm, Frank van Mourik, Andrea Cannizzo, Cristina Consani

Using broadband UV-vis femtosecond transient absorption and fluorescence up-conversion, we investigate the interaction between the haem moiety of ferric and ferrous Horse heart Cytochrome c and its single Tryptophan (Trp) residue and the energy dissipation ...

Elsevier2012

Ultrafast fluorescence studies of dye sensitized solar cells

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo

Time-resolved fluorescence spectra from the RuN719 dye exhibit very short lifetimes (

2012

A femtosecond fluorescence study of vibrational relaxation and cooling dynamics of UV dyes

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo, Thomas James Penfold

We present a femtosecond broad-band fluorescence up-conversion study of the vibrational relaxation dynamics of two UV chromophores, 2,5-diphenyloxazole (PPO) and para-terphenyl (pTP), pumped with a large excess of vibrational energy (>2000 cm(-1)). The ban ...

2012

Femtosecond pump/supercontinuum-probe setup with 20 kHz repetition rate

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Cristina Consani, Gerald Auböck, Roberto Monni

We developed a fast multichannel detection system for pump-probe spectroscopy, capable of detecting single shot super-continuum spectra at the repetition rate (10-50 kHz) of an amplified femtosecond laser system. By tandem pumping the amplifier with three ...

Amer Inst Physics2012

Ultrafast Excited-State Dynamics of Rhenium(I) Photosensitizers [Re(Cl)(CO)(3)(N,N)] and [Re(imidazole)(CO)(3)(N,N)](+): Diimine Effects

Majed Chergui, Olivier Christian Bräm, Amal El Nahhas, Andrea Cannizzo, Cristina Consani

Femto- to picosecond excited-state dynamics of the complexes Re(L)(CO)(3)(N,N) (N,N = bpy, phen, 4,7-dimethyl-phen (dmp); L = Cl, n = 0; L = imidazole, n = 1+) were investigated using fluorescence up-conversion, transient absorption in the 650-285 nm ...

2011

Femtosecond carrier dynamics in bulk graphite and graphene paper

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Gerald Auböck, Fabrizio Carbone

Femtosecond white-light continuum probe transient absorption and reflectivity measurements of bulk graphite and graphene paper are reported. In graphite, the relaxation of photoinduced electron–hole pairs happens through in-plane electron–electron and elec ...

Elsevier2011

Origin of electronic absorption spectra of MLCT-excited and one-electron reduced 2,2 '-bipyridine and 1,10-phenanthroline complexes

Majed Chergui, Amal El Nahhas, Andrea Cannizzo, Cristina Consani

UV-Vis absorption spectra of one-electron reduction products and (MLCT)-M-3 excited states of [(ReCl)-Cl-I(CO)(3)-(N, N)] (N, N = 2,2'-bipyridine, bpy; 1,10-phenanthroline, phen) have been measured by low-temperature spectroelectrochemistry and UV-Vis tran ...

Elsevier2011

Femtosecond UV Studies of the Electronic Relaxation Processes in Cytochrome c

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo, Cristina Consani

We report on an experimental study with UV and visible ultrafast time-gated emission and transient absorption of the early photodynamics of horse heart Cytochrome c in both ferric and ferrous redox states. A clear separation in time and energy of tryptopha ...

2011

Ultrafast (Bio)physical and (Bio)chemical Dynamics

Majed Chergui, Olivier Christian Bräm, Frank van Mourik, Amal El Nahhas, Andrea Cannizzo, Ahmad Ajdar Zadeh Oskouei, Renske Marjan van der Veen, Cristina Consani, Gerald Auböck

We give an overview of our recent work on ultrafast dynamics of chemical (organic dyes, metal-complexes, colloidal quantum dots), and biological (retinal and haem proteins) systems in the liquid phase, studied with a variety of ultrafast optical techniques ...

2011