Publications related to Efficient orange light-emitting electrochemical cells

Ultraviolet Superradiance from Mega-Networks of Tryptophan in Biological Architectures

Majed Chergui, Katrin Elisabeth Oberhofer

Networks of tryptophan (Trp)& horbar;an aromatic amino acid with strong fluorescence response & horbar;are ubiquitous in biological systems, forming diverse architectures in transmembrane proteins, cytoskeletal filaments, subneuronal elements, photorecepto ...

Amer Chemical Soc2024

Investigation of room-temperature single-photon emitters in GaN-based materials and GaN/AlN quantum dots

Johann Nicolaï Stachurski

Over the past decade, quantum photonics platforms aiming at harnessing the fundamental properties of single particles, such as quantum superposition and quantum entanglement, have flourished. In this context, single-photon emitters capable of operating at ...

EPFL2024

The nanoscale impact of individual nonradiative point defects on InGaN/GaN quantum wells

Thomas Fjord Kjaersgaard Weatherley

Today's world depends on optoelectronic devices: light-emitting diodes illuminate our houses and backlight the displays on our gadgets, while laser diodes underpin fibre-optic communication. Such optoelectronic devices rely on crystalline semiconductor het ...

EPFL2023

Full Solution Process of a Near-Infrared Light-Emitting Electrochemical Cell Based on Novel Emissive Ruthenium Complexes of 1,10-Phenanthroline-Derived Ligands and a Eutectic Alloy as the Top Electrode

Mohammad Khaja Nazeeruddin

Near-infrared luminescent materials have recently received considerable attention for a large number of applications, including in solid-state lighting, as bioimaging agents, as photovoltaic cells, and in the telecommunication industry. By adding diverse e ...

AMER CHEMICAL SOC2023

Thiazole Boron Difluoride Dyes with Large Stokes Shift, Solid State Emission and Room-Temperature Phosphorescence

Jieping Zhu, Shuo Tong, Wei Wang

The small Stokes shift and weak emission in the solid state are two main shortcomings associated with the boron-dipyrromethene (BODIPY) family of dyes. This study presents the design, synthesis and luminescent properties of boron difluoro complexes of 2-ar ...

WILEY-V C H VERLAG GMBH2022

Donor-Acceptor-Donor "Hot Exciton" Triads for High Reverse Intersystem Crossing in OLEDs

Anne-Clémence Corminboeuf, Sergio Vela Llausi, Maria Fumanal Quintana, Yanan Zhu

Hot exciton materials have the potential to improve the quantum efficiency of organic light-emitting diodes (OLEDs) by promoting high reversed intersystem crossing (hRISC) between a high-lying triplet (T-n, n >= 2) and a radiative singlet (S-m). In recent ...

WILEY-V C H VERLAG GMBH2022

Single molecule fluorescence and phosphorescence studies using a scanning tunneling microscope

Abhishek Grewal

This thesis investigates novel single-molecule luminescence phenomena at their inherent, sub-molecular length scale. The microscopic understanding of luminescence processes will be crucial for the continued improvement of organic optoelectronic and semicon ...

EPFL2022

Block Copolymer Stabilized Liquid Nanodroplets Facilitate Efficient Triplet Fusion-Based Photon Upconversion in Solid Polymer Matrices

Felipe Andres Saenz Padilla

Sensitized triplet-triplet annihilation-based photon upconversion is a photo-physical process that affords anti-Stokes-shifted emission after annihilation of two metastable triplet excitons of an emitter dye and the formation of a fluorescent singlet state ...

AMER CHEMICAL SOC2021

Enhanced Room-Temperature Photoluminescence Quantum Yield in Morphology Controlled J-Aggregates

Frank Nüesch, Surendra Babu Anantharaman, Jakob Heier

Supramolecular assemblies from organic dyes forming J-aggregates are known to exhibit narrowband photoluminescence with full-width at half maximum of approximate to 9 nm (260 cm(-1)). Applications of these high color purity emitters, however, are hampered ...

2021

Nano-emitting Heterostructures Violate Optical Reciprocity and Enable Efficient Photoluminescence in Halide-Segregated Methylammonium-Free Wide Bandgap Perovskites

Christophe Ballif, Quentin Thomas Jeangros, Peter Joseph Fiala, Chien-Jen Yang, Pietro Caprioglio, Christian Michael Wolff

This work investigates halide segregation in methylammonium-free wide bandgap perovskites by photoluminescence quantum yield (PLQY) and advanced electron microscopy techniques. Our study reveals how the formation of nano-emitting low-energy domains embedde ...

AMER CHEMICAL SOC2021

A general framework for non-exponential delayed fluorescence and phosphorescence decay analysis, illustrated on Protoporphyrin IX

Georges Wagnières, Aurelien Stephen Arnaud Gregor, Emmanuel Louis Arthur Gerelli, Jaroslava Joniová

Delayed fluorescence (DF) is a long-lived luminescence process used in a variety of applications ranging from oxygen sensing in biological tissues to organic Light Emitting Diodes. In common cases, DF results from the deexcitation of the first excited trip ...

2020

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

Direct Observation of Shallow Trap States in Thermal Equilibrium with Band‐Edge Excitons in Strongly Confined CsPbBr 3 Perovskite Nanoplatelets

Jacques-Edouard Moser, Etienne Christophe Socie, Andrés Burgos Caminal, Brener Rodrigo De Carvalho Vale

Lead halide perovskites exhibit great potential for light-emitting devices. Enhanced photoluminescence (PL) is obtained in perovskite materials of reduced dimensionalities due to the large exciton binding energy. However, as the nanocrystal size is reduced ...

2021

Exciton Dynamics in 2D Organic Assemblies for Realization of Next-generation Optoelectronic Devices

Surendra Babu Anantharaman

Supramolecular assemblies of cyanine dye molecules formed by weak van der Waals forces have gained immense attention for their distinct optical properties (high extinction coefficient, narrow absorption and photoluminescence line-width and small Stokes shi ...

EPFL2019

Exciton Dynamics and Effects of Structural Order in Morphology-Controlled J-Aggregate Assemblies

Frank Nüesch, Surendra Babu Anantharaman, Jakob Heier

Narrow-band photoluminescence (PL) together with high quantum efficiency from organic molecules is essential for high-color-purity emitters. Supramolecular assemblies like J-aggregates are promising materials due to their narrow PL signal with full-width a ...

2019

Characterization and Modelling of the Emission Zone and Exciton Dynamics in Doped Organic Light-Emitting Diodes

Markus Regnat

Only recently organic light-emitting diode (OLED) technology has successfully managed the transition from research labs into the consumer market, taking a 60% share of the global mobile display market in 2018. The latest discovery of thermally activated de ...

EPFL2019

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

Photophysics of Deep Blue Acridane- and Benzonitrile-Based Emitter Employing Thermally Activated Delayed Fluorescence

Mohammad Khaja Nazeeruddin, Nikita Drigo, Aron Joel Huckaba

We designed and synthesized a new organic light-emitting diode (OLED) emitter, SBABz4, containing spiro-biacridine donor (D) in the core surrounded by two benzonitrile acceptors (A). The dual A-DxD-A structure is shown to provide pure-blue emission in rela ...

AMER CHEMICAL SOC2018

Nanoscale Lithography and Thermometry with Thermal Scanning Probes

Samuel Tobias Howell, Samuel Zimmermann

Thermal scanning probe lithography (t-SPL) is an advanced lithography technique in which a heated atomic force microscope tip locally modifies a sample material. Due to the nanometer-sized tip apex diameter, t-SPL enables patterning of sub-10 nm structures ...

EPFL2018

Phosphorescent Neutral Iridium (III) Complexes for Organic Light-Emitting Diodes

Mohammad Khaja Nazeeruddin, Aron Joel Huckaba

The development of transition metal complexes for application in light-emitting devices is currently attracting significant research interest. Among phosphorescent emitters, those involving iridium (III) complexes have proven to be exceedingly useful due t ...

Springer Verlag2017