Prof. Aivars Vembris Profile

Prof. Aivars Vembris

Senior researcher at Institute of Solid State Physics, Univ. of Latvia

SPIE Involvement:

Author

Area of Expertise:

Thin organic films , Electroluminescence in organic compounds , Photoluminescence properties of organic meterials , Organic photovoltaic , Charge carrier trap states in organic films , Charge carrier mobility

Publications (28)

Proceedings Article | 30 May 2022 Poster

Poster

Carbene-metal complexes as through-space TADF emitters

Kitija Štucere, Armands Ruduss, Kaspars Traskovskis, Aivars Vembris

Proceedings Volume PC12149, PC121491F (2022) https://doi.org/10.1117/12.2621975

KEYWORDS: Temperature metrology, Quantum efficiency, Metals, Thin films, Luminescence, Copper, Chemical species, System on a chip, Scattering, Phosphorescence

Read Abstract +

Materials for organic light-emitting diodes could be divided into several generations were last 3rd generation organic compounds exhibiting TADF which exhibit up to 100% singlet and triplet state conversation to light without the presence of heavy metal. Organometallic complexes consisting of Cu metal atom is a conceptually different class of low-cost TADF emitters. While this element does not exhibit fast room-temperature phosphorescence, it still can promote a rapid TADF, despite the considerable ΔEST gaps met in such compounds (< 0.05 eV). In this work, we present a novel approach towards TADF emitters where charge transfer through-space and metal-assisted take place. Cu complexes bearing carbazolide and carbene ligands were synthesized. Imidazole-based N-heterocyclic carbenes (NHCs) were used, with electron-accepting sulphonyl groups introduced at 4-position of the N-bound 2,6-diisopropylphenyl (Dipp) substituents. Photoluminescence bands, decays and quantum yields of complexes in various solutions, as well as PMMA-doped films with emitter concentration 5 wt%, were taken. Emission properties of thin films in the temperature diapason from 10 to 300 K were measured to estimate the charge transfer mechanism. For PL bands at room temperature excitation wavelength was either 300 or 375 nm. For temperature-induced CT emission band shifts in vacuum 345 nm excitation wavelength was used, delay 50 ns and width 10 μs. To get PL decays at room temperature a laser with a wavelength of 375 nm was used and decay was measured at the peak wavelength. For temperature-induced decays in vacuum used excitation was 345 nm, time range 50 µs. To get quantum yields at room temperature, emission and scattering ranges of the sample were measured separately with 375 nm excitation. Photoluminescence quantum yield from 0.2 to 0.3 was obtained in solutions but in thin films, it increased up to 0.9 due to the decreased torsional degree of freedom. Emission decays could be described by three exponential functions in all temperature intervals. One featuring a prompt and two delayed emission components. For both delayed emissions, the fastest and slowest emission rate decrease is observed throughout the cooling range, designating a thermally activated nature of the emissive process. The corresponding ΔEST values were estimated from Arrhenius plots and are in the range of 0.0062−0.0075 eV. By combining through-space CT architecture, giving compounds the characteristic low ΔEST values, with the presence of a heavy metal atom, which provides small, but still present SOC.

Proceedings Article | 30 May 2022 Poster

Poster

Laser gain medium of DCM derivatives in active matrix

Patricija Paulsone, Aivars Vembris, Elmars Zarins

Proceedings Volume PC12149, PC1214914 (2022) https://doi.org/10.1117/12.2621171

KEYWORDS: Luminescence, Thin films, Absorption, Quartz, Quantum efficiency, Light sources, Glasses, Energy transfer, Xenon, Spectroscopy

Proceedings Article | 30 May 2022 Presentation

Presentation

Investigations of spontaneous and stimulated emission properties of original glass-forming pyranyliden derivatives in thin films with and without silver nanoparticles

Aivars Vembris, Patricija Pailsone, Raivis Silis, Jelena Mikelsone, Elmars Zarins, Valdis Kokars

Proceedings Volume PC12149, PC121490X (2022) https://doi.org/10.1117/12.2622037

KEYWORDS: Nanoparticles, Thin films, Silver, Luminescence, Nd:YAG lasers, Absorption, Spectroscopy, Solid state lasers, Quantum efficiency, Metals

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Proceedings Article | 30 May 2022 Poster

Poster

Optical and electroluminescence studies of original iridium metal complexes with aromatic staking effect

Margarita Anna Zommere, Kirills Dmitrijevs, Žanis Sisojevs, Kaspars Traskovskis, Valdis Kokars, Aivars Vembris

Proceedings Volume PC12149, PC121491E (2022) https://doi.org/10.1117/12.2621809

KEYWORDS: Organic light emitting diodes, Iridium, Metals, Luminescence, Electroluminescence, Thin films, Quantum efficiency, Glasses, Tin, Spectroscopy

Proceedings Article | 24 May 2022 Presentation + Paper

Presentation + Paper

Enhancement of photoluminescence properties in silver nanoparticles based organic luminophores

A. Vembris, J. Mikelsone

Proceedings Volume 12131, 121310A (2022) https://doi.org/10.1117/12.2620630

KEYWORDS: Nanoparticles, Luminescence, Absorption, Silver, Surface plasmons, Transmission electron microscopy

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Proceedings Article | 24 May 2022 Poster + Paper

Poster + Paper

Amplification of organic semiconductor luminescence in thin films with silver nanoparticles

Raivis Silis, Jelena Mikelsone, Aivars Vembris

Proceedings Volume 12131, 121310V (2022) https://doi.org/10.1117/12.2621545

KEYWORDS: Nanoparticles, Silver, Thin films, Quantum efficiency, Polymethylmethacrylate, Luminescence, Surface plasmons, Absorption, Yield improvement, Ultrasonics

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Proceedings Article | 24 May 2022 Poster + Paper

Poster + Paper

Symmetrical versus asymmetrical molecular configuration in metal-assisted-through-space charge transfer TADF

Aivars Vembris, Kitija Stucere, Kaspars Traskovskis, Armands Ruduss, Zanis Sisojevs

Proceedings Volume 12149, 1214908 (2022) https://doi.org/10.1117/12.2620983

KEYWORDS: Luminescence, Organic light emitting diodes

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Proceedings Article | 24 May 2022 Poster + Paper

Poster + Paper

TADF active carbene-metal-amide complexes exhibiting through-space charge transfer: an impact of metal atom

Kaspars Traskovskis, Annija Jece, Armands Ruduss, Kitija Stucere, Aivars Vembris

Proceedings Volume 12149, 1214909 (2022) https://doi.org/10.1117/12.2621156

KEYWORDS: Chemical species, Luminescence, Gold, Phosphorescence, Copper, Molecules

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Proceedings Article | 1 April 2020 Presentation + Paper

Presentation + Paper

Glassy 2-(1-benzyl-2-styryl-6-methylpyridin-4(1H)-ylidene) fragment containing 1H-indene-1,3(2H)-dione and pyrimidine-2,4,6(1H,3H,5H)-trione derivatives with light-emitting and amplified spontaneous emission properties

Elmars Zarins, Kristine Lazdovica, Karlis Balodis, Aivars Vembris, Valdis Kokars, Julija Pervenecka, Elina Misina

Proceedings Volume 11357, 113571K (2020) https://doi.org/10.1117/12.2553687

KEYWORDS: Absorption, Luminescence, Glasses, Molecules, Thin films, Optical properties, Solid state physics, Spectroscopy, Organic light emitting diodes

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SPIE Journal Paper | 5 December 2018 Open Access

Open Access

Glass-forming nonsymmetric DWK-dyes with 5,5,5-triphenylpentyl and piparazine moieties for light-amplification studies

Elmars Zarins, Toms Puciriuss, Julija Pervenecka, Aivars Vembris, Valdis Kokars

JPE, Vol. 8, Issue 04, 046001, (December 2018) https://doi.org/10.1117/12.10.1117/1.JPE.8.046001

KEYWORDS: Glasses, Absorption, Luminescence, Molecules, Dysprosium, Thin films, Solid state physics, Quantum efficiency, Crystals, Quenching (fluorescence)

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Proceedings Article | 14 September 2018 Paper

Paper

Solution processable piperazine and triphenyl moiety containing non-symmetric bis-styryl-DWK type molecular glasses with light-emitting and amplified spontaneous emission properties

Toms Puciriuss, Julija Pervenencka, Aivars Vembris, Valdis Kokars, Elmars Zarins

Proceedings Volume 10736, 1073620 (2018) https://doi.org/10.1117/12.2319850

KEYWORDS: Glasses, Luminescence, Thin films, Absorption, Quantum efficiency, Solid state physics, Spectroscopy, Molecules, Molecular lasers

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Proceedings Article | 22 May 2018 Paper

Paper

Energy level determination of purine containing blue light emitting organic compounds

Raitis Grzibovskis, Aivars Vembris, Armands Sebris, Zigfrids Kapilinskis, Maris Turks

Proceedings Volume 10687, 106871D (2018) https://doi.org/10.1117/12.2307422

KEYWORDS: Molecules, Ionization, Organic light emitting diodes, Spectroscopy, Thin films, Photoemission spectroscopy

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Proceedings Article | 22 May 2018 Paper

Paper

3,3'-Bicarbazole structural derivatives as charge transporting materials for use in OLED devices

Armands Ruduss, Kaspars Traskovskis, Elina Otikova, Aivars Vembris, Raitis Grzibovskis, Valdis Kokars, Marcis Lielbardis

Proceedings Volume 10687, 1068718 (2018) https://doi.org/10.1117/12.2306850

KEYWORDS: Glasses, Thin films, Absorption, Chromatography, Organic light emitting diodes, Solids, Luminescence, Silica, Molecules, OLED lighting, Fluorescence spectroscopy

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Proceedings Article | 21 May 2018 Paper

Paper

Solution-processable green phosphorescent iridium(III) complexes bearing 3,3,3-triphenylpropionic acid fragment for use in OLEDs

Aivars Vembris, Valdis Kokars, Kaspars Traskovskis

Proceedings Volume 10687, 1068715 (2018) https://doi.org/10.1117/12.2306806

KEYWORDS: Organic light emitting diodes, Molecules, Iridium, Solids, Molecular interactions, Absorption, Luminescence, Photonic integrated circuits, Quantum efficiency, Glasses

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Proceedings Article | 21 May 2018 Paper

Paper

Optical and amplified spontaneous emission of neat films containing 2-cyanoacetic derivatives

Aivars Vembris, Julija Pervenecka, Elmars Zarins, Valdis Kokars

Proceedings Volume 10687, 1068714 (2018) https://doi.org/10.1117/12.2306738

KEYWORDS: Molecules, Luminescence, Thin films, Absorption, Optical properties, Quantum efficiency, Glasses, Solid state lasers, Dye lasers, Molecular lasers

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Proceedings Article | 21 May 2018 Paper

Paper

Investigation of photoluminescence and amplified spontaneous emission properties of cyanoacetic acid derivative (KTB) in PVK amorphous thin films

Julija Pervenecka, Aivars Vembris, Elmars Zarins, Valdis Kokars

Proceedings Volume 10687, 1068717 (2018) https://doi.org/10.1117/12.2306835

KEYWORDS: Luminescence, Molecules, Thin films, Absorption, Polymers, Ocean optics, Quantum efficiency, Molecular interactions, Solid state physics, Laser damage threshold

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Proceedings Article | 27 April 2016 Paper

Paper

Amplified spontaneous emission of pyranyliden derivatives in PVK matrix

Valdis Kokars, Aivars Vembris, Elmars Zarinsh

Proceedings Volume 9895, 989509 (2016) https://doi.org/10.1117/12.2227841

KEYWORDS: Molecules, Molecular aggregates, Molecular lasers, Laser development, Dye lasers, Laser systems engineering, Glasses, Polymers, Doping, Luminescence, Laser glasses, Absorption, Quantum efficiency, Ocean optics, Solid state physics, Molecular interactions, Thin films

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Proceedings Article | 27 April 2016 Paper

Paper

Study of the P3HT/PCBM interface using photoemission yield spectroscopy

Raitis Grzibovskis, Aivars Vembris

Proceedings Volume 9895, 98950Q (2016) https://doi.org/10.1117/12.2227823

KEYWORDS: Energy, Interfaces, Ultraviolet radiation, Ionization, UV-Vis spectroscopy, Heterojunctions, Organic materials, Solar energy, Ionization, Organic materials, Thin films, Ultraviolet radiation, Ionization spectroscopy, Organic photovoltaics, Molecules, Spectroscopy

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Proceedings Article | 22 October 2014 Paper

Paper

Thermal and optical properties of 4H-pyran-4-ylidene fragment and bis-styryl and triphenyl groups containing derivatives

Elmars Zarins, Aivars Vembris, Valdis Kokars, Martins Rutkis

Proceedings Volume 9421, 942105 (2014) https://doi.org/10.1117/12.2083938

KEYWORDS: Absorption, Luminescence, Glasses, Optical properties, Thin films, Solid state physics, Solids, Molecules, Temperature metrology, Molecular lasers

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Proceedings Article | 1 May 2014 Paper

Paper

Amplified spontaneous emission of glass forming DCM derivatives in PMMA films

Aivars Vembris, Elmars Zarinsh, Valdis Kokars

Proceedings Volume 9137, 91371E (2014) https://doi.org/10.1117/12.2052508

KEYWORDS: Luminescence, Molecules, Polymers, Polymethylmethacrylate, Dielectrics, Quantum efficiency, Absorption, Ocean optics, Glasses, Solid state physics

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Proceedings Article | 1 May 2014 Paper

Paper

Photoelectrical properties of indandione fragment containing azobenzene compounds

Kaspars Pudzs, Dagnija Blumberga, Janis Latvels, Aivars Vembris, Raitis Grzibovskis

Proceedings Volume 9137, 91371G (2014) https://doi.org/10.1117/12.2052604

KEYWORDS: Molecules, Thin films, Ionization, Absorption, Solar energy, Quantum efficiency, Electrodes, Molecular electronics, Solar cells, Silicon

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Proceedings Article | 1 May 2012 Paper

Paper

Synthesis, optical, and thermal properties of glassy trityl group containing luminescent derivatives of 2-tert-butyl-6-methyl-4H-pyran-4-one

Valdis Kampars, Inta Muzikante, Karina Siltane, Kristine Lazdovica, Aivars Vembris, Elmars Zarins, Elina Misina, Valdis Kokars, Martins Rutkis

Proceedings Volume 8435, 84351Q (2012) https://doi.org/10.1117/12.921996

KEYWORDS: Glasses, Absorption, Solids, Molecules, Solid state physics, Optical properties, Thin films, Polymers, Organic light emitting diodes, Nonlinear optics

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Proceedings Article | 1 May 2012 Paper

Paper

Light-emitting thin films of glassy forming organic compounds containing 2-tert-butyl-6-methyl-4H-pyran-4-ylidene

Kaspars Pudzs, Aivars Vembris, Inta Muzikante

Proceedings Volume 8435, 843527 (2012) https://doi.org/10.1117/12.922694

KEYWORDS: Molecules, Electroluminescence, Absorption, Thin films, Luminescence, Polymers, Molecular interactions, Excitons, Organic light emitting diodes, Glasses

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SPIE Journal Paper | 1 January 2011 Open Access

Open Access

Pyranylidene indene-1,3-dione derivatives as an amorphous red electroluminescence material

Aivars Vembris, Martins Porozovs, Inta Muzikante, Valdis Kokars, Elmars Zarins

JPE, Vol. 1, Issue 1, 011001, (January 2011) https://doi.org/10.1117/12.10.1117/1.3524819

KEYWORDS: Electroluminescence, Organic light emitting diodes, Molecules, Absorption, Electrodes, Solids, Thin films, Aluminum, Luminescence, Light sources

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Proceedings Article | 25 April 2008 Paper

Paper

Influence of corona poling procedures on linear and non-linear optical properties of polymer materials containing indandione derivatives as a cromophores

Aivars Vembris, Elina Laizane, Martins Rutkis

Proceedings Volume 6999, 699924 (2008) https://doi.org/10.1117/12.781334

KEYWORDS: Crystals, Nonlinear optics, Molecules, Chromophores, Polymers, Second-harmonic generation, Optical properties, Crystallography, Electro optic polymers, Optics manufacturing

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Proceedings Article | 12 June 2006 Paper

Paper

All-optical poling of DMABI molecules in a polymer matrix

Jean-Michel Nunzi, Sylvie Dabos-Seignon, Andrey Tokmakov, Martins Rutkis, Inta Muzikante, Aivars Vembris, Aleksandra Apostoluk

Proceedings Volume 5946, 59460P (2006) https://doi.org/10.1117/12.639195

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Proceedings Article | 20 April 2006 Paper

Paper

Novel second-order nonlinear optical polymer materials containing indandione derivativatives as a chromophore

Andrejs Tokmakovs, Martins Rutkis, Valdis Kampars, Aivars Vembris, Andrejs Jurgis, Egils Fonavs, Vismants Zauls

Proceedings Volume 6192, 61922Q (2006) https://doi.org/10.1117/12.661937

KEYWORDS: Chromophores, Nonlinear optics, Polymers, Molecules, Second-harmonic generation, Absorbance, Absorption, Glasses, Chemical species, Polymer thin films

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Proceedings Article | 8 August 2003 Paper

Paper

Optically induced degradation of some betaine dyes

Andrey Tokmakov, Ojars Neilands, Aivas Vembris, Andrejs Jurgis, Inta Muzikante

Proceedings Volume 5122, (2003) https://doi.org/10.1117/12.515774

KEYWORDS: Molecules, Polymers, Polymer thin films, Absorption, Absorbance, Oxygen, Polymethylmethacrylate, Quartz, Thin films, Gold

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Showing 5 of 28 publications

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