Prof. René A.J. Janssen Profile

Prof. René A.J. Janssen

Professor at Technische Univ Eindhoven

SPIE Involvement:

Author

Publications (17)

Proceedings Article | 3 October 2022 Open Access

Thin-film solution-processed multijunction solar cells

René Janssen

Proceedings Volume PC12209, PC1220901 (2022) https://doi.org/10.1117/12.2639415

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Proceedings Article | 7 March 2022 Poster

Photoluminescence of thin film semiconductors affected by extrinsic effects

Tom van der Pol, Matthew Dyson, Kunal Datta, Stefan Meskers, René Janssen

Proceedings Volume PC11996, PC119960I (2022) https://doi.org/10.1117/12.2604832

KEYWORDS: Thin films, Luminescence, Semiconductors, Systems modeling, Data modeling, Solar cells, Reverse modeling, Refractive index, Perovskite, Organic semiconductors

Proceedings Article | 20 August 2020 Poster

Extending the range of useful polymers in non-fullerene acceptor based solar cells using a ternary solvent system

Tom van der Pol, Martijn Wienk, René Janssen

Proceedings Volume 11474, 114741B (2020) https://doi.org/10.1117/12.2566071

KEYWORDS: Polymers, Solar cells, External quantum efficiency, Organic photovoltaics, Fullerenes, Fabrication, Analytical research, Absorption, Luminescence, Thin films

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Proceedings Article | 18 September 2018 Open Access

Multi-junction polymer solar cells: Status and challenges (Conference Presentation)

René A. Janssen

Proceedings Volume 10737, 1073706 (2018) https://doi.org/10.1117/12.2321322

KEYWORDS: Solar cells, Polymers, External quantum efficiency, Organic photovoltaics, Photoactive materials, Multijunction solar cells, Quantum efficiency

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Proceedings Article | 23 May 2018 Presentation

Tandem near-infrared organic photodiodes (OPDs) for future application in artificial retinal implants (Conference Presentation)

Giulio Simone, Dario Di Carlo, Stefan Meskers, René Janssen, Gerwin Gelinck

Proceedings Volume 10687, 106870K (2018) https://doi.org/10.1117/12.2307566

KEYWORDS: Electrodes, Photodetectors, Capacitance, Near infrared, Tin, Signal attenuation, Neurons, Eye, Neuroimaging, Brain

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Age-related retinal diseases lead to blindness due to progressive loss of image-capturing photoreceptor neural cells, which are responsible for the conversion of light entering the eye into electrical signals that are sent to the brain. Retinitis pigmentosa and age-related macular degeneration are two leading causes of severe visual losses in adult individuals, affecting over 1 million people worldwide. In these diseases, rod and cone photoreceptor cells are progressively lost while neural cells in the retinal network remain functional. Electronic retinal prostheses have great potential to restore sight by electrical stimulation of the surviving neurons. In this project, we aim at developing an artificial retinal implant based on organic photodetectors (OPDs). Neural stimulation is provided by an OPD pixel array processed on ultrathin plastic foil. Upon illumination with near-infrared (NIR) light, photo-generated electrical charge in each OPD pixel is delivered to the biological tissue via stimulating electrodes. Flexibility and softness of organic materials allow to interface intimately with neurons so that electrical signals generated by the implant are translated into bio-signals. Firstly, we investigated the photovoltaic performance of NIR-sensitive OPDs based on polymer:fullerene bulk heterojunction. We used PDPP3T:PCBM photoactive layer to detect NIR light up to 930 nm. We showed that by going from a single to a tandem OPD the open-circuit voltage can be doubled and the charge threshold for neural stimulation can be reached at lower light intensities. This results in a more efficient cellular stimulation while maintaining high implant resolution. Furthermore, we analysed the stimulating electrode behavior in a biological-like environment. We characterized the double-layer capacitance of gold, platinum and titanium nitrite (TiN) electrodes by pulsed-voltage measurements in phosphate buffered saline solution (PBS). We observed that TiN exhibits the highest charge capacitance due to the high surface roughness, which enables to maximize the charge injection into the electrolyte. Using a combination of experimental work and modeling we studied the process of charge injection into the biological tissue. We simulated the injected charge during 1 ms NIR light pulse under different illumination conditions. We compared the performance of retinal implants based on single or tandem OPD pixels coupled to 20 µm stimulating electrodes. As we expected, tandem OPD pixels always maximize charge injection into the electrolyte due to their higher photo-voltage. Moreover, the high double-layer capacitance of TiN electrodes metal electrodes results in sufficient charge injection levels for neural stimulation, which is generally achieved between 1 and 4 nC. In conclusion, we predicted that neural activity can be triggered using organic photovoltaic pixels in combination with high charge capacitance electrode materials. These findings are paving way to the development of a high-resolution retinal prostheses based on organic soft materials.

Proceedings Article | 5 October 2015 Presentation

Kinetic Monte Carlo simulation of the efficiency roll-off, emission color, and degradation of organic light-emitting diodes (Presentation Recording)

Reinder Coehoorn, Harm van Eersel, Peter Bobbert, Rene A. Janssen

Proceedings Volume 9566, 956610 (2015) https://doi.org/10.1117/12.2187416

KEYWORDS: Monte Carlo methods, Organic light emitting diodes, Spatial resolution, Molecules, Video, Current controlled current source

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SPIE Journal Paper | 10 December 2014

Charge transfer state energy in ternary bulk-heterojunction polymer–fullerene solar cells

Sandra Kouijzer, Weiwei Li, Martijn Wienk, René A. Janssen

JPE, Vol. 5, Issue 01, 057203, (December 2014) https://doi.org/10.1117/12.10.1117/1.JPE.5.057203

KEYWORDS: External quantum efficiency, Polymers, Fullerenes, Solar cells, Solar energy, Absorption, Data modeling, Heterojunctions, Binary data, Transmission electron microscopy

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Proceedings Article | 28 August 2009 Paper

Design and synthesis of side-chain functionalized regioregular poly(3-hexylthiophene)-based copolymers and application in polymer:fullerene bulk heterojunction solar cells

B. Campo, W. Oosterbaan, J. Gilot, T. Cleij, L. Lutsen, R. A. Janssen, D. Vanderzande

Proceedings Volume 7416, 74161G (2009) https://doi.org/10.1117/12.825881

KEYWORDS: Polymers, Absorption, Solar cells, Polymer thin films, Heterojunctions, Bromine, Crystals, Quartz, Fullerenes, Interfaces

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Proceedings Article | 26 April 2006 Paper

Organic multi-junction solar cells processed from solution with sensitivity from ultraviolet to the near infrared

Afshin Hadipour, Bert de Boer, Jurjen Wildeman, Floris Kooistra, Jan Hummelen, Mathieu G. R. Turbiez, Martijn Wienk, Rene A. J. Janssen, Paul W. M. Blom

Proceedings Volume 6192, 61920D (2006) https://doi.org/10.1117/12.664850

KEYWORDS: Absorption, Polymers, Electrodes, Solar cells, Organic photovoltaics, Excitons, Heterojunctions, Optical resonators, Solar energy, Photons

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