Breakthrough Device Harvests and Emits Light

A newly developed organic semiconductor device can both generate electricity from light and emit bright visible light, as reported by researchers from Science Tokyo. By carefully designing a material where energy losses are suppressed, the team achieved efficient power conversion and electroluminescence simultaneously, demonstrating a multifunctional platform with potential applications in displays, sensors, and energy-harvesting technologies.

Towards Organic Devices That Can Both Harvest and Emit Light

At the foundation of modern electronics lies the semiconductor diode, serving as one of the main building blocks of integrated circuits, displays, camera sensors, and solar panels. However, existing diode-based devices only excel at one job while remaining fundamentally unable to perform the others; smartphone screens can display vibrant images but cannot capture sunlight, whereas a solar panel can generate electricity but will never act as a display. This raises an intriguing question: If these technologies share the same physical foundation, could a single device perform these roles at once?

In a recent study, a research team led by Associate Professor Seiichiro Izawa from the Materials and Structures Laboratory, Institute of Integrated Research, Institute of Science Tokyo (Science Tokyo), Japan, along with Professor Yutaka Majima and doctoral student Qing-Jun Shui from Science Tokyo; Associate Professor Naoya Aizawa from the Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Japan; and Professor Ken-ichi Nakayama and doctoral student Jinyao Xu from the Graduate School of Engineering, The University of Osaka, Japan, have developed a device that can both harvest light and emit it, opening the door to power-generating displays and more compact electronics. Their work was published online in the journal Advanced Materials on April 20, 2026.

The team tackled a persistent challenge in the field of organic semiconductors. When light excites these materials, it generates mobile charges-namely electrons and their positively charged counterparts known as 'holes.' Ideally, when these charges recombine, they should either produce electricity or emit light. Instead, much of the energy is lost as heat through a process called non-radiative recombination.

To mitigate this issue, the research team focused on controlling how energy flows at the interface between two organic materials. They carefully selected and combined multi-resonance thermally activated delayed fluorescence (MR-TADF) materials, in which electron density alternates across adjacent atoms. This unique arrangement creates an ideal energy-level architecture that prevents captured energy from transferring to non-emissive states.

The researchers used two MR-TADF molecules widely used in OLED technology, called v-DABNA and QAO, in a simple layered structure. Their device achieved 1.36% power-conversion efficiency and 2.0% light-emission efficiency simultaneously, marking the first time an organic device has exceeded 1% in both categories. It emitted bright red light with a luminance of 1,000 cd/m2, matching the brightness of commercial smartphone displays. Importantly, the device operated at just 3.2 volts, making it compatible with standard lithium-ion batteries, and achieved an open-circuit voltage remarkably close to the theoretical limit.

Based on these impressive results, the fabricated device approaches the performance of well-established inorganic semiconductors like gallium arsenide. "This demonstration of simultaneous high-efficiency light emission, energy harvesting, and photodetection within a single device establishes a new design framework for organic optoelectronics and represents a significant step toward truly multifunctional, compact, and sustainable device platforms," remarks Izawa.

Beyond these performance metrics, organic semiconductors offer unique advantages over inorganic alternatives like perovskites. "Organic devices can be fabricated as lightweight, mechanically flexible, and even semitransparent films, making them highly attractive for applications such as window-integrated photovoltaics, wearable and skin-mounted electronics, and conformable display sensor systems, all of which require form factors that are difficult to realize using rigid materials," explains Izawa.

Overall, the team expects this work to contribute to the development of power-generating displays and improved efficiency in solar cells and other light-energy harvesting technologies.

Authors:

Qing-Jun Shui¹, Naoya Aizawa^2,3, Jinyao Xu², Atsuko Nihonyanagi⁴, Daigo Miyajima^4,5, Ken-ichi Nakayama², Yutaka Majima¹, and Seiichiro Izawa^1*

*Corresponding author

Title:

Highly-Emissive Organic Photovoltaics Approaching Theoretical Limit Voltage and Enabling Multifunctional Energy-Harvesting Displays

Journal:

Advanced Materials

DOI:

10.1002/adma.72995

Affiliations:

¹Materials and Structures Laboratory, Institute of Science Tokyo, Japan

²Division of Applied Chemistry, The University of Osaka, Japan

³Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Japan

⁴RIKEN Center for Emergent Matter Science (CEMS), Japan

⁵School of Science and Engineering, The Chinese University of Hong Kong, P. R. China