Fresh Faces, Breakthroughs, and Big Milestones
As summer unfolds, we’re delighted to bring you some exciting updates from the Fluxim team: new people, a new webinar, a milestone in FEM simulation of OLEDs and PVs, and new research highlights that push the boundaries of optoelectronic device development.
Welcome Matthias and Daniel!
We are thrilled to welcome Dr. Matthias Diethelm back to Fluxim! Matthias rejoins us following his postdoctoral work at Empa and the University of Oxford, where he contributed extensively to the development of CIGS and perovskite solar cells. With a PhD from EPFL and a strong publication record in ion-based optoelectronics, OLEDs, and solar cells, Matthias brings deep expertise and creative energy. We're very happy to have him back!
We also extend a warm welcome to Daniel Parsons, who joins as a new PhD student. Daniel previously worked at the UK’s National Physical Laboratory, focusing on the characterisation of innovative semiconductors for photovoltaics. At Fluxim, he’s now investigating degradation and optimization of indoor PV devices as part of the MENTOR project, in collaboration with UPC. Welcome aboard, Daniel!
New Research Highlights
Our tools continue to support groundbreaking academic and industrial work. Here are three recent highlights from our customers:
Surfing the Color Map with Carbazole-Appended Cyclometalated N-Heterocyclic Carbene Pt Complexes and Their Application in Green Organic Light-Emitting Devices
J. Roy, et al., Adv. Optical Mater., 2500051, (2025). https://doi.org/10.1002/adom.202500051
This research article published in March 2025 focuses on the synthesis and application of novel platinum (II) complexes, specifically carbazole-appended cyclometalated N-heterocyclic carbenes, as emitters in organic light-emitting devices (OLEDs). The research details the stage-wise creation of new complexes (1A/B, 2A/B, 3A/B) and characterises their electrochemical and photophysical properties, including their bright phosphorescent emission in the blue to blue-green spectrum. A significant finding is the influence of doping concentration on emission colour, particularly for complex 1A, which shifts from blue to yellowish-green due to aggregate formation. The paper concludes by presenting the high performance of OLEDs using these complexes, with notable efficiency achieved through ultrathin, non-doped emissive layers.
How Fluxim’s R&D Tools supported this work
Phelos was used to measure the angle- and polarization-dependent light emission of the OLED devices.
Paios was used for transient electroluminescence decay measurements.
Setfos was used for optical device simulations, including cavity effects.
These tools played a key role in understanding and optimizing the photophysical and electroluminescent behavior of the platinum complexes in OLEDs.
Enhancing Indoor Photovoltaic Efficiency to 37.6% Through Triple Passivation Reassembly and n-Type to p-Type Modulation in Wide Bandgap Perovskites
S. Huang, et al., Adv. Funct. Mater. 2502152, (2025). https://doi.org/10.1002/adfm.202502152
Congratulations to our colleagues at UCL/Imperial College London/London South Bank University/EPFL for their remarkable results.
This work tackles the challenge of improving wide bandgap perovskite solar cells (WB-PSCs) for indoor energy harvesting. The team developed a Triple Passivation Treatment (TPT) to reduce defects and improve long-term stability under low light conditions. Their method enhances charge extraction and slows down degradation, helping the devices maintain performance over time.
The result? A notable efficiency of 37.6% under indoor lighting, along with improved operational stability — a major step forward for indoor photovoltaics.
Fluxim’s Paios at Work
To support these findings, the team used our Paios platform for advanced device characterization. Measurements included C-V, EIS, TPC, TPV, IMPS, and IMVS — all conducted in ambient conditions.
Congratulations to first author Siming Huang et al. for these great results.
White light-emitting electrochemical cells based on metal-free TADF emitters
Tang, S., Tsuchiya, Y., Wang, J. et al. Nat Commun 16, 653 (2025). https://doi.org/10.1038/s41467-025-55954-3
Our customers from Umeå University and Kyushu University have achieved a significant milestone by demonstrating the first white light-emitting electrochemical cell (LEC) based solely on metal-free TADF emitters.
This is a crucial development because conventional white LECs often rely on non-sustainable metals or are limited in efficiency by only converting singlet excitons. By using Thermally Activated Delayed Fluorescence (TADF) emitters, which can harvest both singlet and triplet excitons for light emission while being metal-free, these limitations are addressed.
How they did it
The team developed a single-layer active material comprising:
• Two color-complementary metal-free TADF guest emitters: blue-emitting 4CZ-BN and orange-emitting TPA-DCPP6.
• A metal-free blend host (TCTA and 26DCzPPy) that enables efficient energy transfer to the emitters.
• A metal-free ionic liquid electrolyte (THABF4) providing mobile ions for electrochemical doping.
Through careful tuning of the relative concentrations of these components (optimized to a mass ratio of 50:50:50:0.8:10 for TCTA:26DCzPPy:4CZ-BN:TPA-DCPP:THABF4), they were able to control energy transfer processes and the formation of the electrochemical doping structure.
A key aspect was positioning the emissive p-n junction near the center of the active layer to suppress quenching effects.
The Results
The developed white TADF-LEC delivers:
• High-quality white light emission that is angle-invariant.
• A high Color Rendering Index (CRI) of 88–90.
• A bright luminance of 350 cd/m2 at an External Quantum Efficiency (EQE) of 2.11% and current efficacy of 4.55 cd/A. Peak luminance could exceed 1500 cd/m2.
• Color coordinates close to ideal white (e.g., CIE: 0.36, 0.38) and a Correlated Color Temperature (CCT) in the 4400–5000K range.
• An operational lifetime of 40 hours above 100 cd/m2.
• Remarkable spectral stability, with the broadband EL spectrum remaining essentially invariant during long-term operation.
This work demonstrates that competitive white LEC performance can be achieved using sustainable, metal-free emitter materials, paving the way for cost- and energy-efficient ambient-air printing of flexible white LECs.
The researchers used Setfos to analyze and simulate the angle-dependent EL spectrum, which helped determine the position of the emissive p-n junction within the active material.
Congratulations to the teams for these impressive results and for your trust in Setfos.
You can find more recent publications on our Research Overview page.
Webinar: Boosting Indoor photovoltaic Efficiency
For our 14th webinar, we are pleased to welcome Prof. Dr Mojtaba Abdi-Jalebi from University College London.
Mojtaba will present the following talk:
Boosting Indoor Photovoltaic Efficiency in Wide Bandgap Perovskite Solar Cells Through Triple Passivation Reassembly
Webinar | Tuesday, July 1st, 2025 | 10:00am – 11:00am CEST
The webinar will be hosted by Dr. Daniele Braga from Fluxim and is open to all researchers from academia and industry with an interest in solar cell research.
Register now to secure your place and stay at the forefront of OLED innovation.
We look forward to seeing you there!
Celebrating 10 Years of Laoss
Following on from our 20 years of Setfos celebration last year, we have another simulation milestone to celebrate: 10 years of Laoss - Fluxim’s industry-trusted software for electrothermal and optical simulation of large-area OLEDs and solar cells. Laoss’ inception and evolution have been primarily down to a small team of dedicated researchers and software engineers: Roman Heistand, Dr. Sandra Jenatsch, Dr. Balthasar Blülle, Dr. Urs Aeberhard and Dr. Matthias Diethelm. Thanks for your involvement and continued commitment to Laoss.
Used by leading R&D teams in academia and industry, Laoss enables the simulation of OLED arrays, PV modules, and large-area devices with unmatched flexibility and accuracy. From electrode layout optimization to ray-tracing light extraction and electrothermal modeling, Laoss helps researchers design, test, and scale their devices with confidence.
Why Laoss?
Optimize grid layouts and reduce ohmic losses
Model heating and current distribution with 2D FEM
Simulate 3D optical structures with ray tracing
Integrate with Setfos for vertical and lateral analysis
Import experimental data (e.g. from Paios, Phelos) to validate your models
Proven in research
Laoss has powered peer-reviewed publications from top institutions like CSEM, TU Eindhoven, and OLEDWorks. Whether you're working on curved OLED lighting or printable solar modules, Laoss supports your innovation from lab to prototype.
Try Laoss Free for 1 Month
Curious to see what Laoss can do for your research? We're offering a free 1-month evaluation license—no strings attached.
Here’s to the next decade of advanced simulation with Laoss.
Supporting the Indoor PV Community at IPVC-2
Fluxim is happy to sponsor the 2nd Indoor Photovoltaics Conference (IPVC-2), taking place 9–11 July 2025 at Villa Mondragone in Monte Porzio Catone (Rome). This unique event gathers leading voices in indoor PV research to explore materials, characterization, modeling, and commercialization for low-light energy harvesting.
📍 Location: Villa Mondragone, near Rome
📅 Dates: 9–11 July 2025
Fluxim´s Research Contributions to IPVC-2
Ph.D student Daniel Parsons will be presenting a poster at IPVC-2:
Simulation and characterisation of recombination mechanisms in indoor organic photovoltaics
Dr. Antonio Cabas Vidani will also be presenting a contributing talk at the conference. As product manager for Litos and Litos Lite he will be happy to discuss with you how these instruments can help with your research. He´ll be especially happy to tell you about the latest version of Litos Lite which is due for release in early July.
Learn more: fluxim.com/events
Thank you for staying connected with us—enjoy the summer and keep innovating!
The Fluxim Team