SPIE Optics and Photonics 2025: Plenary Session Evaluation of Organic Materials for Optoelectronics

The use of organic materials in photonics has given rise to many device innovations for applications in sensing, semiconductors, lasers, and more. The Organic Photonics + Electronics plenary session at SPIE Optics + Photonics 2025, taking place through 7 August in San Diego, California, sampled some current research efforts in this subfield, and looked at developments on the horizon.

Ruth Shinar delivers her plenary talk

Triplet-to-singlet upconversion

The first speaker,Chihaya Adachi—a professor at Kyushu University and one of the world’s leading researchers on OLEDs—discussed recent advances in organic photonics, focusing on triplet-to-singlet upconversion mechanisms, and the need for improvements in blue emitters for commercial uses. He discussed thermoluminescent dosimeter (TLD) optimization for higher performance and longer device lifetimes, as well as the potential for these materials in, for example, organic solar cells.

Adachi’s presentation also introduced the concept of organic thermoelectric devices using a p-n junction to generate holes and electrons. The device architecture, he said, includes a charge generation layer and a transport layer. Experiments under dark conditions show small “quite promising,” measurable thermoelectric behavior, indicating potential applications for things like power-generation textiles and smart contact lenses.

Organic photodetectors and OLEDs

Outgoing symposium chair, Zakya H. Kafafi of Lehigh University, introduced the next speaker, Ruth Shinar of Iowa State University of Science and Technology. Kafafi noted, “I am Egyptian by birth and American by choice,” whereas Shinar and her spouse are originally from Israel. “So, these are two of my friends and colleagues I have worked with for many, many years,” she said, “and it’s an example of science without borders.”

Shinar’s presentation included an overview of organic photodetectors (OPD) and OLEDs in devices like sensors, spectrometers-on-a-chip, and devices that could also incorporate microfluidic channels. She noted their current use and potential future in optical sensing devices, including devices that are compact, field deployable, and wearable, and suited for applications that range from environmental monitoring to medical diagnostics.

“The big question, of course, is why OLEDs?” Shinar said. The answer: “The devices can be made on almost every substrate you can think of,” including plastics that are bendable and stretchable.”

Inkjet printing of opto-electronic devices

The third speaker for the organic photonics and electronics plenary was Emil J.W. List-Kratochvil of Humboldt University, who spoke about the evolution of his work with ink-jet printing technology and its ongoing promise for optoelectronic devices, including light-emitting devices and solar cells.

As an additive technology, he said, ink-jet printers allow for rapid prototyping and hybrid integration of components, though he cautioned against trying to print everything on a device so as to avoid printing components whose requirements would be too time consuming. “We have shown that heterogenous, homogenous integration is the way to go.”

List-Kratochvil discussed the various inks developed for printing opto-electronic devices, including metal halides and perovskites. Today’s challenges, he said, include printing layers of different inks which require precise timing of deposition and drying so that new layers do not disrupt those already set down on the substrate.

Current and future directions for research, he said, include combining printing with automated testing, integrating printed solar cells, and scaling print size. Finally, he mentioned printing of RGB devices, noting challenges in achieving high-performance in blue-emitting perovskites.

Source: optics.org