Publication date: 14th September 2021
Due to their potential for high-efficiency optoelectronic devices, the behavior of organic semiconductors has garnered increasing interest in recent years. Understanding the transport of excitons by diffusion of singlets and triplets is essential for developing efficient optoelectronic devices. Measuring the characteristically non-emissive triplets, however, continues to challenge the field. In this work, we have developed a unique method to trace the position of the triplet exciton in the emissive layer of organic light emitting diode (OLEDs) by analyzing angle-resolved delayed electroluminescence emission patterns as a function of time. This study could provide exciton transport kinetics in the transverse direction from the substrate plane. Furthermore, direct visualization of the delayed photoluminescence imaging technique could provide lateral transport kinetics of triplet excitons. We have studied the effect of polymer chain packing on triplet diffusion in the polyfluorene based polymeric system, which is known to give efficient OLED efficiency for display devices. Further, this polyfluorene system exhibits an efficient triplet-triplet fusion process, which provides singlet excitons as delayed fluorescence and becomes a tool to study triplet exciton kinetics. Results suggest that, in the thicker polymeric semiconductor films, diffusivity approaches close to ultrahigh 10-3 cm2s-1, which is similar to the values that are reported for acene-based molecular crystalline thin films. Our results also provide important insight into efficient electroluminescence in unusually thick (1.2 mm) polyfluorene-based emissive layers of OLEDs.
We thank Cambridge Display Technology (CDT) Ltd. for supplying the F8BT. We also acknowledge the support of the NCPRE in allowing the use of the device fabrication facility. G.B. acknowledges funding support of DST for the research fellowship. R.H.F. and D.K. acknowledge the funding support from the RCUK- funded SUNRISE project. We also would like to acknowledge Christopher R. McNeil for the discussion on SAXS data.
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.