Publications by Beat Ruhstaller

Alleviating nanostructural phase impurities enhances the optoelectronic properties, device performance and stability of cesium-formamidinium metal-halide perovskites

Christophe Ballif, Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Beat Ruhstaller, Mostafa Rabie Shlaly Bahr Othman, Daniel Anthony Jacobs, Christian Michael Wolff, Anaël Morgane Jaffrès, Austin George Kuba

The technique of alloying FA+ with Cs+ is often used to promote structural stabilization of the desirable alpha-FAPbI3 phase in halide perovskite devices. However, the precise mechanisms by which these alloying approaches improve the optoelectronic quality ...

Royal Soc Chemistry2024

Scrutinizing thermally stimulated current transients originating from trapped charges in organic semiconductors: A drift-diffusion study

Frank Nüesch, Beat Ruhstaller

Thermally stimulated current (TSC) is a widely used technique to assess trap states and extract their density, energy, and capture rate using analytical expressions. In many cases, the latter are derived from physical models pertaining to inorganic semicon ...

AIP Publishing2022

Routes for Efficiency Enhancement in Fluorescent TADF Exciplex Host OLEDs Gained from an Electro-Optical Device Model

Frank Nüesch, Beat Ruhstaller, Markus Regnat

Fluorescence-based organic light-emitting diodes (OLEDs) using thermally activated delayed fluorescence (TADF) have increasingly attracted attention in research and industry. One method to implement TADF is based on an emitter layer composed of an exciplex ...

WILEY2020

The Dynamic Emission Zone in Sandwich Polymer Light-Emitting Electrochemical Cells

Frank Nüesch, Balthasar Bluelle, Beat Ruhstaller, Roland Hany, Matthias Diethelm

In light-emitting electrochemical cells (LECs), the position of the emission zone (EZ) is not predefined via a multilayer architecture design, but governed by a complex motion of electrical and ionic charges. As a result of the evolution of doped charge tr ...

WILEY-V C H VERLAG GMBH2019

Influence of the bias-dependent emission zone on exciton quenching and OLED efficiency

Beat Ruhstaller, Markus Regnat

We present an electro-optical model of a three-layer phosphorescent OLED which accurately describes the measured current efficiency and transient electroluminescence decay for different biases. Central findings are a bias-dependent emission zone, which inf ...

2019

Analysis of the Bias-Dependent Split Emission Zone in Phosphorescent OLEDs

Beat Ruhstaller, Markus Regnat

From s-polarized, angle-dependent measurements of the electroluminescence spectra in a three-layer phosphorescent organic light-emitting diode, we calculate the exciton distribution inside the 35 nm thick emission layer. The shape of the exciton profile ch ...

2018

Design of perovskite/crystalline-silicon monolithic tandem solar cells

Christophe Ballif, Jérémie Werner, Beat Ruhstaller, Björn Niesen

2018

Organic Salt Semiconductor with High Photoconductivity and Long Carrier Lifetime

Frank Nüesch, Beat Ruhstaller, Roland Hany, Donatas Gesevicius

2018

Time-Dependent p-i-n Structure and Emission Zone in Sandwich-Type Light-Emitting Electrochemical Cells

Frank Nüesch, Beat Ruhstaller, Roland Hany, Matthias Diethelm

2018

Visible light-emitting host-guest electrochemical cells using cyanine dyes

Frank Nüesch, Beat Ruhstaller, Roland Hany, Lei Wang, Surendra Babu Anantharaman, Jakob Heier

Light-emitting electrochemical cells (LECs) can be fabricated as a single emissive organic/salt layer sandwiched between two electrodes, offering cost-effective next generation signage and lighting applications. Cyanine dyes are especially attractive to ex ...

Elsevier Science Bv2017

Doping Evolution and Junction Formation in Stacked Cyanine Dye Light-Emitting Electrochemical Cells

Matia Bulloni, Beat Ruhstaller, Roland Hany, Lei Wang

Cyanine dyes are fluorescent organic salts with intrinsic conductivity for ionic and electronic charges. Recently (J. Am. Chem. Soc. 2013, 135, 18008-18011), these features have been exploited in cyanine light-emitting electrochemical cells (LECs). Here, w ...

Amer Chemical Soc2016

Light trapping in solar cells: numerical modeling with measured surface textures

Christophe Ballif, Franz-Josef Haug, Mathieu Gérard Boccard, Thomas Andreas Lanz, Beat Ruhstaller

We present and experimentally validate a computational model for the light propagation in thin-film solar cells that integrates non-paraxial scalar diffraction theory with non-sequential ray-tracing. The model allows computing the spectral layer absorbance ...

Optical Society of America2015

Influence of Molybdenum Oxide Interface Solvent Sensitivity on Charge Trapping in Bilayer Cyanine Solar Cells

Frank Nüesch, Beat Ruhstaller, Roland Hany

Bilayer organic solar cells based on trimethine cyanine donor and C-60 acceptor materials have been fabricated by coating the trimethine dye from solution on molybdenum oxide (MoO3) anode buffer layer. The choice of deposition solvent drastically influence ...

Amer Chemical Soc2014

Electrothermal Finite-Element Modeling for Defect Characterization in Thin-Film Silicon Solar Modules

Christophe Ballif, Mathias Bonmarin, Michael Elias Stückelberger, Thomas Andreas Lanz, Beat Ruhstaller, Christian Frédéric Schlumpf

We present and validate a finite-element model for coupled charge and heat transport in monolithically interconnected thin-film solar modules. Using measured current-voltage (I-V) and lock-in thermography (LIT) measurements of amorphous silicon minimodules ...

Institute of Electrical and Electronics Engineers2013