Comparative photophysical study of Pt(II) complex-nanoclay hybrid materials as dry powders and hydrogels

2020 ◽  
Vol 75 (11) ◽  
pp. 991-996
Author(s):  
Sathish Chatnahalli Gangadharappa ◽  
Cristian A. Strassert
Keyword(s):  
Excited State ◽  
Coordination Compounds ◽  
Molecular Level ◽  
Structural Features ◽  
Time Resolved ◽  
Dry Powders ◽  
Water Dispersibility ◽  
Photophysical Study ◽  
Time Resolved Photoluminescence

AbstractThe excited state properties of Pt(II) complexes are strongly influenced by their microenvironment and by intermolecular interactions. In this work, we investigated the photoluminescence of six Pt(II) complexes adsorbed onto a layered nanoclay, namely Laponite® (LAP). The excellent water dispersibility and gel-forming nature of the LAP was exploited to achieve a class of versatile materials. In particular, we report on the comparative photophysics of the dry powders and the hydrogels. Steady-state and time-resolved photoluminescence spectroscopy were used to assess the role of structural features at molecular level on the interaction between the nanodiscs, which in turn affects the intermolecular coupling of the coordination compounds in the excited state.

Tuning the excited-state deactivation pathways of dinuclear ruthenium(ii) 2,2′-bipyridine complexes through bridging ligand design

2020 ◽  
Vol 49 (24) ◽  
pp. 8096-8106 ◽  
Author(s):  
Simon Cerfontaine ◽  
Ludovic Troian-Gautier ◽  
Sara A. M. Wehlin ◽  
Frédérique Loiseau ◽  
Emilie Cauët ◽  
...  
Keyword(s):  
Excited State ◽  
Steady State ◽  
Variable Temperature ◽  
Ligand Design ◽  
Binuclear Complexes ◽  
Time Resolved ◽  
Bridging Ligand ◽  
Dinuclear Ruthenium ◽  
Photophysical Study ◽  
Time Resolved Photoluminescence

A detailed photophysical study of binuclear complexes was performed using steady-state and time-resolved photoluminescence measurements at variable temperature. The results were compared with the prototypical [Ru(bpy)3]2+.

Time-resolved photoluminescence and excited state structure of Bi3+ center in YAlO3

2014 ◽  
Vol 36 (10) ◽  
pp. 1705-1708 ◽  
Author(s):  
A. Krasnikov ◽  
L. Lipińska ◽  
E. Mihokova ◽  
M. Nikl ◽  
T. Shalapska ◽  
...  
Keyword(s):  
Excited State ◽  
State Structure ◽  
Time Resolved ◽  
Time Resolved Photoluminescence

scholarly journals Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3904
Author(s):  
Kaveendra Maduwantha ◽  
Shigeyuki Yamada ◽  
Kaveenga Rasika Koswattage ◽  
Tsutomu Konno ◽  
Takuya Hosokai
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Room Temperature ◽  
Photophysical Properties ◽  
Density Functional Theory Calculations ◽  
Time Resolved ◽  
Excited State Dynamics ◽  
Unique Material ◽  
Potential Applications ◽  
Time Resolved Photoluminescence

Room-temperature phosphorescent (RTP) materials have been attracting tremendous interest, owing to their unique material characteristics and potential applications for state-of-the-art optoelectronic devices. Recently, we reported the synthesis and fundamental photophysical properties of new RTP materials based on benzil, i.e., fluorinated monobenzil derivative and fluorinated and non-fluorinated bisbenzil derivative analogues [Yamada, S. et al., Beilstein J. Org. Chem. 2020, 16, 1154–1162.]. To deeply understand their RTP properties, we investigated the excited-state dynamics and photostability of the derivatives by means of time-resolved and steady-state photoluminescence spectroscopies. For these derivatives, clear RTP emissions with lifetimes on the microsecond timescale were identified. Among them, the monobenzil derivative was found to be the most efficient RTP material, showing both the longest lifetime and highest amplitude RTP emission. Time-resolved photoluminescence spectra, measured at 77 K, and density functional theory calculations revealed the existence of a second excited triplet state in the vicinity of the first excited singlet state for the monobenzil derivative, indicative of the presence of a fast intersystem crossing pathway. The correlation between the excited state dynamics, emission properties, and conformational flexibility of the three derivatives is discussed.

Origin of strong red emission in Er3+-based upconversion materials: role of intermediate states and cross relaxation

2019 ◽  
Vol 21 (43) ◽  
pp. 24026-24033 ◽  
Author(s):  
Chiho Lee ◽  
Heeyeon Park ◽  
Woong Kim ◽  
Sungnam Park
Keyword(s):  
Upconversion Luminescence ◽  
Photoluminescence Spectroscopy ◽  
Cross Relaxation ◽  
Time Resolved ◽  
Red Emission ◽  
Intermediate States ◽  
Time Resolved Photoluminescence

Comprehensive NIR-to-visible upconversion luminescence mechanism in Er3+-based materials is elucidated by wavelength-dependent, power-dependent, and time-resolved photoluminescence spectroscopy.

scholarly journals Ultrafast valence to non-valence excited state dynamics in a common anionic chromophore

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
James N. Bull ◽  
Cate S. Anstöter ◽  
Jan R. R. Verlet
Keyword(s):  
Excited State ◽  
Internal Conversion ◽  
Rydberg States ◽  
Bound State ◽  
Photoactive Yellow Protein ◽  
Coumaric Acid ◽  
Photoelectron Imaging ◽  
Time Resolved ◽  
Valence States

AbstractNon-valence states in neutral molecules (Rydberg states) have well-established roles and importance in photochemistry, however, considerably less is known about the role of non-valence states in photo-induced processes in anions. Here, femtosecond time-resolved photoelectron imaging is used to show that photoexcitation of the S1(ππ*) state of the methyl ester of deprotonated para-coumaric acid – a model chromophore for photoactive yellow protein (PYP) – leads to a bifurcation of the excited state wavepacket. One part remains on the S1(ππ*) state forming a twisted intermediate, whilst a second part leads to the formation of a non-valence (dipole-bound) state. Both populations eventually decay independently by vibrational autodetachment. Valence-to-non-valence internal conversion has hitherto not been observed in the intramolecular photophysics of an isolated anion, raising questions into how common such processes might be, given that many anionic chromophores have bright valence states near the detachment threshold.

Nonlinear Optical and Transport Properties of Fullerene Crystals

1994 ◽  
Vol 359 ◽  
Author(s):  
Hugh J. Byrne ◽  
Lidia Akselrod ◽  
Andreas T. Werner ◽  
Wolfgang K. Maser ◽  
Mathias Kaiser ◽  
...  
Keyword(s):  
Phase Transition ◽  
Excited State ◽  
Nonlinear Dependence ◽  
High Excited State ◽  
Time Resolved ◽  
Highly Nonlinear ◽  
Observed Behaviour ◽  
State Densities ◽  
Photochemical Modification ◽  
Time Resolved Photoluminescence

ABSTRACTPicosecond time resolved photoluminescence and photoconductivity measurements are performed to investigate the influence of high intensity illumination on the properties of Fullerene crystals. A highly nonlinear dependence of both the photoluminescence characteristics and the photoconductive response of the fullerenes is seen and temperature dependent measurements indicate that the nonlinear processes are associated with an insulatormetal-like phase transition in the material, and thus that the electronic properties of the excited state are dramatically altered at high excited state densities. The observed behaviour is compared and contrasted to the changes in the optical properties upon photochemical modification of the pristine material via Raman spectroscopy. Application of a simple phenomenological model to calculate the contribution of intermolecular exchange and correlation energies in the excited state supports the proposal that the observed phenomena originate from a Mott-like phase transition. A further manifestation of this behaviour is the emergence of a broadband electroluminescent emission above a critical injection current density.

scholarly journals Excited-State Dynamics of Room-Temperature Phosphorescent Organic Materials Based on Monobenzil and Bisbenzil Frameworks

2020 ◽  
Author(s):  
Kaveendra Maduwantha ◽  
Shigeyuki Yamada ◽  
Kaveenga Rasika Koswattage ◽  
Tsutomu Konno ◽  
Takuya Hosokai
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Room Temperature ◽  
Photophysical Properties ◽  
Density Functional Theory Calculations ◽  
Time Resolved ◽  
Excited State Dynamics ◽  
Unique Material ◽  
Potential Applications ◽  
Time Resolved Photoluminescence

Room-temperature phosphorescent (RTP) materials have been attracted tremendous interest owing to their unique material characteristics and potential applications for state-of-the-art optoelectronic devices. Recently, we have reported a synthesis and fundamental photophysical properties of new RTP materials based on benzil, i.e., fluorinated monobenzil derivative and fluorinated and non-fluorinated bisbenzil derivative analogues [Yamada, S. et al, Beilstein J. Org. Chem. 2020, 16, 1154–1162.]. To further understand their RTP properties, here we investigated the excited-state dynamics and photostability of the derivatives by means of time-resolved and steady-state photoluminescence spectroscopies. For these derivatives, clear RTP emissions with lifetimes on the microsecond timescale were identified. Among them, the monobenzil derivative was found to be the most efficient RTP material, showing both the longest lifetime and highest amplitude RTP emission. Time-resolved photoluminescence spectra measured at 77 K and density functional theory calculations revealed the existence of a second excited triplet state in the vicinity of the first excited singlet state for the monobenzil derivative, indicative of the presence of a fast intersystem crossing pathway. A discussion of the correlation between the excited state dynamics, emission properties, and conformational flexibility of the three derivatives is presented.

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