▼Click each molecule for an explanation!
One exciton can split into two through the process of fission. Doubling the number of excitons could double the output current of solar cells and improve efficiency. New materials and a deeper understanding of the process are needed to fully utilize fission.
One exciton can trigger other excitons to emit light with the exact same properties. This process is the basis for creating organic lasers that could make lasers widely available. Many challenges still remain to meet the stringent requirements for lasing.
A molecule can gain extra energy in the form of an exciton when a positive (electron) and negative (hole) charge meet. The exciton can release this energy by emitting light. This emission can be used for displays, lighting, sensors, and more.
Excitons can also be created by absorbing energy from light. By then separating the positive and negative charges in the exciton, electricity can be generated. Organic materials are a path to flexible, lightweight, and low-cost solar cells.
Through appropriate molecular design, light with a rotating electric field, called circularly polarized, can be emitted. This kind of emission can be useful for new types of displays, optical storage systems, sensors, and more.
By suppressing the processes that destroy excitons, energy can be stored in excitons for longer periods of time before being released. These processes of storage and delayed release are under investigation for new applications.
We are hard at work studying relationships between molecular structure and physical properties, creating new materials, and developing new device structures to exploit excitons and establish the next generation of electronics based on organic materials.
An exciton is an energetic state in semiconductors that can be thought of as a bound negative (electron) and positive (hole) charge. Excitons directly affect the electrical and optical properties and behavior of devices and films that use organic materials as semiconductors. The engineering and controlling of processes related to excitons is key to fully unlocking the potential of organic semiconductors and optoelectronics. With the possibility for flexible, lightweight, and low-cost devices and uses ranging from displays and lasers to power generation and transistors, the next generation of organic electronics will play a growing role in everyday life.
Organic optoelectronics, organic semiconductor device
properties, organic photo-
physics and photochemistry
devices, OLEDs, OTFTs
Molecular Design and Synthesis Group Leader
Device-Oriented Breakthrough Group Leader
Organic lasers, OLEDs, organic-inorganic hybrid devices
Unique Physical Processes Group Leader
physics, device physics
To further the fundamental understanding of excitons and fully harness them, the ADACHI Molecular Exciton Engineering Project was founded under the Exploratory Research for Advanced Technology (ERATO) program of the Japan Science and Technology Agency (JST) in 2013 and will run until March 2019. This project is exploring novel molecular excitonic processes in organic thin films and pioneering their related basic photophysics, device physics, and materials science. We aim to engineer and control undeveloped excitonic processes and design novel materials and optoelectronic devices with new functionalities. Through this, we will create both high-performance devices and new, innovative devices that will unlock additional applications, with one major goal of achieving organic semiconductor lasers. These advances are expected to contribute to organic electronics helping to shape the future of society.
The facilities at OPERA house a wide variety of equipment for the creation and characterization of new materials, films, and devices including fully-equipped synthesis labs for over 30 people, NMR, TG-DTA, multiple vacuum train sublimation systems, over nine vacuum deposition systems connected to gloveboxes, an e-beam lithography system, optical labs, an XRD system, UV-Vis-NIR spectrophotometer, photoluminescence spectrometer, PLQY measurement system, streak camera, and OLED, OPV, and OTFT measurement systems.
The ADACHI Molecular Exciton Engineering Project is based at the Center for Organic Photonics and Electronics Research (OPERA) at Kyushu University, Ito Campus, in Fukuoka, Japan. The center was established in 2010 to create new advances in organic electronics and will continue that goal through this project. Collaborative investigators include research groups from other departments at Kyushu University and groups at other universities including Kyoto University and Waseda University.
The endless possibilities for the molecular design of organic com- pounds makes the realization of a wide variety of new functions and applications achievable. The potential for developments in optoelectronics is particularly high. Through our ERATO project, we aim to clarify undeveloped excitonic processes, primarily in organic thin-films, and create new devices such as organic semiconductor lasers. By exploiting such processes in this project, we believe new molecules that overturn traditional thinking will be produced. To accomplish this, we will strive to forge a fresh research environment conducive to multidisciplinary research and truly creative thinking by establishing a team of international researchers on the leading edge and forming collaborations with researchers from a broad range of backgrounds.
Explaining how chemical structures affect material properties and creating appropriate molecules is paramount to understanding the nature of excitons and completely utilizing them. This group aims to clarify the relationships between structure and function and to develop new molecules for light emis- sion, singlet fission, exciton storage, and oriented growth by attacking molecular design from both quantum chemical and empirical fronts and feeding the properties of obtained molecules back into the design process.
Excitonic processes can be controlled not only by material choice but also by developing new device structures. This group will explore new types of OLEDs, solar cells, transistors, thermoelectric generators, and other devices with solid-state films, liquid-state semiconductors, and single crystals to effectively control and harness excitonic processes. Our ultimate goal is to realize solid-state organic lasers and environmentally-friendly bio-electronics devices.
The unique physical processes of excitons and ways to control them are still not fully understood. This group’s focuses include exploring the physics of exciton dynamics, studying in detail how deposition processes can affect molecular orientation and thereby exciton dynamics, and exploiting energy transfer processes to develop new devices.