Edoardo Stanzani, Stefano Sem, Simon Züfle, Beat Ruhstaller, Sandra Jenatsch,

Organic Electronics, Volume 139, 2025, 107204, ISSN 1566-1199,

https://doi.org/10.1016/j.orgel.2025.107204.

This research by the Fluxim research team investigates the degradation mechanisms of thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs). By combining experimental measurements with device simulations, the study identifies the formation of hole and electron traps at the HTL/EML interface as the primary cause of efficiency reduction. The researchers pinpoint hole traps within the hole transport layer (HTL) as the main contributor to the OLED's decreased performance. Their findings provide crucial insights into improving the operational stability of TADF OLEDs, a technology currently limited by its insufficient lifetime. The study uses a variety of techniques to analyse the degradation, including capacitance-voltage measurements and current-voltage characterisation. The ultimate aim is to improve the lifespan of OLED devices for use in commercial displays.

Othman, M., Jeangros, Q., Jacobs, D. A., Futscher, M. H., Zeiske, S., Armin, A., Jaffrès, A., Kuba, A. G., Chernyshov, D., Jenatsch, S., Züfle, S., Ruhstaller, B., Tabean, S., Wirtz, T., Eswara, S., Zhao, J., Savenije, T. J., Ballif, C., Wolff, C. M., & Hessler-Wyser, A. (2024). Energy & Environmental Science. The Royal Society of Chemistry.

DOI: https://doi.org/10.1039/D4EE00901K

This study investigates the effects of cationic alloying in cesium-formamidinium perovskite films on optoelectronic properties and solar cell performance. It finds that precise Cs+ tuning minimizes structural faults and enhances photoconductivity, with encapsulated devices maintaining 85% of initial efficiency after 1400 hours under continuous illumination, providing insights into defect tolerance and stability mechanisms in perovskite materials.

Fluxim's Research Tools

In the study, Fluxim's Paios system was used for conductivity measurements, and Litos for accelerated aging tests under thermal and photonic stress, evaluating the stability of perovskite solar cells.

Rohit D. Chavan, Bartłomiej Bończak, Joanna Kruszyńska, Apurba Mahapatra, Muhammad Ans, Jan Nawrocki, Kostiantyn Nikiforow, Pankaj Yadav, Jan Paczesny, Faranak Sadegh, Muhittin Unal, Seckin Akin, and Daniel Prochowicz

Chemistry of Materials 2023 35 (19), 8309-8320

DOI: 10.1021/acs.chemmater.3c01995

This study introduces a novel azahomofullerene (AHF-4) as an interlayer in perovskite solar cells (PSCs), enhancing charge transfer and film quality while reducing recombination. AHF-4 outperforms the standard fullerene derivative PCBM, achieving higher efficiency (21.43%) and better stability under light and heat, promising advancements in PSC performance and durability.

How Litos Lite and Litos were used

The photovoltaic performance was evaluated using a Fluxim Litos Lite setup, equipped with a Wavelabs Sinus LS2 solar simulator with AM 1.5 spectrum for excitation.

Aging tests were also performed using a Fluxim Litos setup, and 1 Sun equivalent illumination with no UV component, holding the substrates at 45 ± 5 °C in a N2 atmosphere and using an MPP tracking algorithm.

Andrés-Felipe Castro-Méndez, Jamie P. Wooding, Selma Fairach, Carlo A. R. Perini, Emily K. McGuinness, Jacob N. Vagott, Ruipeng Li, Sanggyun Kim, Vivek Brahmatewari, Nicholas Dentice, Mark D. Losego, and Juan-Pablo Correa-Baena

ACS Energy Lett. 2023, 8, 1, 844–852

Publication Date: January 3, 2023

https://doi.org/10.1021/acsenergylett.2c02272

This study investigates the use of vapor phase infiltration (VPI) to improve the stability of organic charge transport layers, such as hole-selective spiro-OMeTAD in perovskite solar cells (PSCs) and other organic electronic devices.

By using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and grazing incident wide-angle X-ray scattering (GIWAXS), the study identifies that infiltration of TiOx via VPI hinders the crystallization of the spiro-OMeTAD layer. The infiltrated PSCs retained over 80% of their original efficiency after an operando stability test of 200 hours at 75°C, double the efficiency retained by devices without infiltration. This study suggests VPI can be used to stabilize organic charge transport layers and prolong device lifetimes.

Device stability measurements were carried out by tracking the maximum power point (MPP) of the devices while keeping constant the temperature of the films (by Peltier pads) at 75 °C using the stability measurement platform Litos from Fluxim.

Carlo Andrea Riccardo Perini, Esteban Rojas-Gatjens, Magdalena Ravello, Andrés-Felipe Castro-Mendez, Juanita Hidalgo, Yu An, Sanggyun Kim, Barry Lai, Ruipeng Li, Carlos Silva-Acuña, and Juan-Pablo Correa-Baena

Adv. Mater. 2022, 34, 2204726

https://doi.org/10.1002/adma.202204726

This study investigates the impact of bulky-cation-modified interfaces on the stability of halide perovskite solar cells, which has not been extensively explored. The research demonstrates the thermal instability of these interface layers used in state-of-the-art solar cells and reveals changes in the chemical composition and structure of the films under thermal stress, which affects charge-carrier dynamics and device operation. The type of cation used for surface treatment also affects the extent of these changes, with long carbon chains providing more stable interfaces. The study emphasizes the importance of prolonged annealing of the treated interfaces to enable reliable reporting of performance and inform the selection of different bulky cations.

Device Characterization: The photovoltaic performance was evaluated using a Fluxim Litos Lite setup, equipped with a Wavelabs Sinus-70 AAA solar simulator with AM1.5 spectrum for excitation.

Aging tests were performed using a Fluxim Litos setup, using 1 Sun equivalent illumination with no UV-component, holding the substrates at 55 °C in a N2 atmosphere and using an MPP tracking algorithm. Every 12 h, a J–V scan in reverse and forward direction was automatically acquired.

Perini, Carlo and Rojas-Gatjens, Esteban and Ravello, Magdalena and Castro Mendez, Andres Felipe and Hidalgo, Juanita and An, Yu and Li, Ruipeng and Silva-Acuña, Carlos and Correa-Baena, Juan-Pablo

doi.org/10.2139/ssrn.3921344

10 Sep 2021

The impact on device stability of the bulky cation-modified interfaces in halide perovskite solar cells is not well-understood. In this paper the research team demonstrate the thermal instability of the bulky cation interface layers used in some of the highest performing solar cells to date.

The photovoltaic performance was evaluated using a Fluxim Litos Lite setup, equipped with a Wavelabs Sinus-70 AAA solar simulator with AM1.5 spectrum for excitation. The current voltage (J-V) characteristics were acquired with forward and reverse scans at a scan rate of 50 mV s-1. The stabilized power output was acquired using a maximum power point tracking algorithm for 60 s. Devices were not preconditioned before measurement. Masking was used during the measurement, defining a pixel area of 0.0625 cm2. Nitrogen was flown in the measurement chamber during characterization. No temperature control was applied. Aging tests were performed using a Fluxim Litos setup, using 1 Sun equivalent illumination with no UV-component, holding the substrates at 55 °C in a N2 atmosphere and using a maximum power point tracking algorithm. Every 12 h a J-V scan in reverse and forward direction was automatically acquired.