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Photoluminescence of combinatorically sputtered Al₂O₃–Y₂O₃ thin films with a Cr³⁺ and Nd³⁺ co-doping concentration gradient

Derksen, M. (author), Bizinoto Ferreira Bosco, G. (author), Muller, Timo (author), van der Kolk, E. (author)

The characterization of a wide range of luminescent thin films can be a long and tedious endeavor. With reactive combinatorial sputtering of multiple metal targets, it possible to fabricate thin films with a gradient in composition simply by not rotating the substrate. In this work, combinatorically sputtered thin films of Cr³⁺ and...

journal article 2024

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Evaluating the Tm2+ 4f125d1 → 4f13 and 4f13 → 4f13 Luminescence and Quenching Dynamics in Orthorhombic BaCl2

Plokker, M.P. (author), Vlaar, S.A. (author), Bakx, A.H.J. (author), van der Kolk, E. (author), Dorenbos, P. (author), Hintzen, H.T.J.M. (author)

The luminescence properties of Tm2+-doped BaCl2 with an orthorhombic structure have been studied as a function of temperature and compared to other Tm2+-doped chlorides. In addition to the 2F5/2 → 2F7/2 (4f13 → 4f13) line emission, two 4f125d1 → 4f13 band emissions are observed at 20 K that can be ascribed to the spin-allowed (3H6,5d1)S=1/2 →...

journal article 2023

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High-Strength Amorphous Silicon Carbide for Nanomechanics

Xu, M. (author), Shin, D. (author), Sberna, P.M. (author), van der Kolk, R.J.H. (author), Cupertino, A. (author), Bessa, M.A. (author), Norte, R.A. (author)

For decades, mechanical resonators with high sensitivity have been realized using thin-film materials under high tensile loads. Although there are remarkable strides in achieving low-dissipation mechanical sensors by utilizing high tensile stress, the performance of even the best strategy is limited by the tensile fracture strength of the...

journal article 2023

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High-Quality Amorphous Silicon Carbide for Hybrid Photonic Integration Deposited at a Low Temperature

Lopez Rodriguez, B. (author), van der Kolk, R.J.H. (author), Aggarwal, Samarth (author), Sharma, N. (author), Li, Z.Z.L. (author), van der Plaats, D.W. (author), Scholte, T.C. (author), Chang, J. (author), Groeblacher, S. (author), Pereira, S.F. (author), Bhaskaran, Harish (author), Esmaeil Zadeh, I.Z. (author)

Integrated photonic platforms have proliferated in recent years, each demonstrating its unique strengths and shortcomings. Given the processing incompatibilities of different platforms, a formidable challenge in the field of integrated photonics still remains for combining the strengths of different optical materials in one hybrid integrated...

journal article 2023

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Metal-insulator multilayer precursors for enhanced Sm²⁺ absorption and Tm²⁺ luminescence in SiAlO thin films prepared by magnetron sputtering

Bizinoto Ferreira Bosco, G. (author), van den Biesen, J. K. (author), Boers, C. D. (author), Simone, G. (author), Kao, C.C. (author), Tichelaar, F.D. (author), Boshuizen, B. (author), van der Kolk, E. (author)

Silicon-aluminum-oxigen (SiAlO) coatings doped with Sm²⁺ and prepared by reactive magnetron co-sputtering of Si, Al, and Sm targets, are attractive for luminescence solar concentrator applications but suffer from the low absorption between 300 and 600 nm. This article reports that the main cause of low absorption is a high...

journal article 2022

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Efficient computation of states and sensitivities for compound structural optimisation problems using a Linear Dependency Aware Solver (LDAS)

Koppen, S. (author), van der Kolk, M. (author), van den Boom, S.J. (author), Langelaar, Matthijs (author)

Real-world structural optimisation problems involve multiple loading conditions and design constraints, with responses typically depending on states of discretised governing equations. Generally, one uses gradient-based nested analysis and design approaches to solve these problems. Herein, solving both physical and adjoint problems dominates...

journal article 2022

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Low-aspect ratio appendages for wind-assisted ships

van der Kolk, N.J. (author), Akkerman, I. (author), Keuning, J.A. (author), Huijsmans, R.H.M. (author)

Wind propulsion for commercial ships has been identified as a key component in the energy transition for the maritime industry. The sailing hybrid ship will operate with leeway (drift) angles to produce a lateral force known as sideforce, for steady operation under sail. In this paper, experimental results for the sailing performance of ships...

journal article 2021

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Experimental and numerical analysis of Tm²⁺ excited-states dynamics and luminescence in CaX₂ (X = Cl, Br, I)

Plokker, M.P. (author), van der Knijff, I.C. (author), de Wit, A.V. (author), Voet, B. (author), Woudstra, T. (author), Khanin, V. (author), Dorenbos, P. (author), van der Kolk, E. (author)

The prospect of using Tm²⁺-doped halides for luminescence solar concentrators (LSCs) requires a thorough understanding of the temperature dependent Tm²⁺ excited states dynamics that determines the internal quantum efficiency (QE) and thereby the efficiency of the LSC. In this study we investigated the dynamics in CaX<sub...

journal article 2021

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Photoluminescence and excited states dynamics of Tm²⁺-doped CsCa(Cl/Br)₃ and CsCa(Br/I)₃ perovskites

Plokker, M.P. (author), Biner, D. A. (author), Dusoswa, N. (author), Dorenbos, P. (author), Krämer, K. W. (author), van der Kolk, E. (author)

In this study, we systematically vary the Cl/Br and Br/I ratios in CsCaX₃:Tm²⁺ (X = Cl, Br, I) and hereby gradually shift the positions of the Tm²⁺ 4f¹²5d¹-levels as relative to the two 4f¹³ levels. At low temperatures up to five distinct Tm²⁺ 4f¹²5d<sup>1...

journal article 2021

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The potential of transparent sputtered NaI:Tm²⁺, CaBr₂:Tm²⁺, and CaI₂:Tm²⁺ thin films as luminescent solar concentrators

Merkx, E.P.J. (author), Plokker, M.P. (author), van der Kolk, E. (author)

The parameters governing the performance of a luminescent solar concentrator (LSC) are determined for sputtered thin-films of NaI:Tm²⁺, CaBr₂:Tm²⁺, and CaI₂:Tm²⁺. These parameters are determined by using six gradient thin film material libraries, combinatorially sputtered from metallic...

journal article 2021

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Optical and structural characterization of Tm₂O₃, TmN, and TmO_xN_y thin films grown by direct-current reactive magnetron sputtering

Meeuwissen, A.A. (author), Bizinoto Ferreira Bosco, G. (author), van der Kolk, E. (author)

This paper reports the fabrication and characterization of several thulium oxide and nitride thin films grown by reactive magnetron direct-current sputtering. Hysteresis curves of the Tm emission spectra of the sputtering plasma versus the flow of N₂ or O₂ around the Tm-metal target were monitored. Emission spectra of...

journal article 2021

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Sailing Efficiency and Course Keeping Ability of Wind Assisted Ships

van der Kolk, N.J. (author)

doctoral thesis 2020

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Improved Prediction of the Energy Demand of Fuel Cell Driven Expedition Cruise Ships

Boertz, C. (author), Hekkenberg, R.G. (author), van der Kolk, Richard (author)

Fuel cell systems require a better early-stage prediction of the energy consumption of a ship because they are more expensive, more voluminous and less able to deal with rapid load changes than conventional diesel-powered systems. This paper discusses a model for such an improved prediction of the total energy demand of an expedition cruise...

conference paper 2020

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Towards Tm²⁺ in sialon thin films grown by sputtering using the gradient deposition

Bizinoto Ferreira Bosco, G. (author), van der Kolk, E. (author)

The valence stability parameter (E_Ff), defined as the difference between the charge transfer energy to the host intrinsic Fermi energy, was used as criterion to analyze the capability of different host materials within the SiAlON class to stabilize divalent thulium. Available data on charge transfer energies and optical bandgap...

conference paper 2020

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Concentration and temperature dependent luminescence properties of the SrI₂-TmI₂ system

Plokker, M.P. (author), Hoogsteen, W. (author), Abellon, R.D. (author), Krämer, K. W. (author), van der Kolk, E. (author)

The concentration dependent luminescence of the SrI₂-TmI₂ system was investigated. For Tm²⁺ concentrations up to 5 mol %, the quantum efficiency (QE) of the ²F_5/2→²F_7/2 emission exhibits a constant value above 50%. The QE drops for higher Tm²⁺...

journal article 2020

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Functionalizing window coatings with luminescence centers by combinatorial sputtering of scatter-free amorphous SiAlON: Eu²⁺ thin film composition libraries

Merkx, E.P.J. (author), van Overbeek, S. (author), van der Kolk, E. (author)

SiAlON window coatings are applied on an industrial scale to achieve e.g. scratch-resistance and anti-reflection. Doping these SiAlONs with rare-earths adds luminescent functionality, which could be applied in photovoltaics. By using a combinatorial reactive sputtering approach, an amorphous thin film composition library with a Si:Al ratio...

journal article 2019

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Case study: Wind-assisted ship propulsion performance prediction, routing, and economic modelling

van der Kolk, N.J. (author), Bordogna, G. (author), Mason, J.C. (author), Desprairies, P. (author), Vrijdag, A. (author)

In this paper, a vessel model for the performance of wind-assisted ships is combined with a routing tool to assess the fuel savings available from the installation of both one and two Flettner rotors when travelling along a Great Circle Route path. This is combined with an economic analysis to assess commercial viability for these hybrid...

conference paper 2019

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4f→5d and anomalous emission in Yb²⁺ doped NaI, SrI₂ and LaI₃ powders prepared by rapid melting and quenching in vacuum

Hendriks, M.H.P. (author), van der Kolk, E. (author)

The temperature dependent luminescence properties of Yb2+ doped in NaI, SrI2 and LaI3 powders, prepared by a fast synthesis method involving the rapid melting and quenching in vacuum are reported. The 4f→5d excitation and emission spectra obtained for SrI2:Yb2+ were found to be in accordance with earlier work validating the synthesis methods. In...

journal article 2019

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Modelling and optimization of UV absorbing photovoltaic windows using a thin film AlN:Eu³⁺ luminescence library

Merkx, E.P.J. (author), Lensvelt, T.G. (author), van der Kolk, E. (author)

Building-integrated photovoltaics are drawing much attention to make the built environment self-sufficient in terms of electricity. Luminescent solar concentrators (LSCs) can provide this electricity generation when used as photovoltaic windows. Paramount to an efficient LSC are non-overlapping absorption and emission spectra, to avoid self...

journal article 2019

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Temperature dependent relaxation dynamics of luminescent NaX:Tm²⁺ (X=Cl, Br, I)

Plokker, M.P. (author), van der Kolk, E. (author)

In recent years, Thulium in its 2 + oxidation state has been identified as candidate dopant in halide hosts for luminescent solar concentrators. Yet, some of its luminescent properties with regard to these applications remain unexplored. In this study we report on the temperature dependent photo-luminescent behaviour of NaCl:Tm²⁺,...

journal article 2019