Displays using electrochemical reactions offer exciting possibilities. These systems have electrodes and electrolytes. By putting the glowing and coloring molecules on the electrodes instead of the electrolyte, displays can be made more efficient and stable. Benefits include:
- Saving energy
- Changing colors
- Reducing costs
- Increasing flexibility
- Improving durability
Researchers from Chiba University, Japan, developed a low-power device using clay materials to combine light emission and color control. This device is sustainable and adaptable for displays, digital signage, and sensors.
The device embeds light-emitting europium(III) complexes and color-changing viologen derivatives in a layered clay matrix, allowing control of light and color at low voltage. This eco-friendly approach could revolutionize display technology and sensors.
The team, led by Professors Norihisa Kobayashi and Kazuki Nakamura, with Ms. Rong Cao and Mr. Naoto Kobayashi, created a dual-mode electrochemical device that emits light and changes color, making it highly adaptable and energy-efficient.
Prof. Kobayashi said, “Our approach introduces a game-changing concept in dual-mode display design by uniting luminescence and coloration within a single device. This advancement not only enhances performance but also expands the versatility of displays across diverse environments.”
The device uses a clay compound called smectite, which has great ion exchange and adsorption properties. This clay helps stabilize and enhance two key components: europium(III) complexes (which provide bright light) and heptyl viologen derivatives (which enable color changes). Together, these materials create a solution that controls light and color.
The team combined Eu(III), hexafluoroacetylacetone, and triphenylphosphine oxide to create a complex. They applied hybrid films of smectite, HV2+, and the Eu complex onto electrodes. When a voltage was applied, the HV2+ molecules produced a vivid cyan color, and the luminescence from the Eu complex was quenched. This showed precise control over both functions.
This innovation is both scientifically important and environmentally friendly. It reduces energy consumption and uses low-voltage operations, addressing sustainability concerns. Clay compounds offer an eco-friendly alternative to synthetic materials.
Experiments showed that the device works well under different conditions. The clay’s structure interacts with the embedded molecules, enhancing performance and allowing faster, more efficient reactions.
Prof. Nakamura explains the applications of these devices: “This technology bridges the gap between energy-efficient reflective displays and high-visibility emissive screens. Its adaptability to lighting conditions makes it an ideal solution for various applications, from digital signage to portable devices.”
Applying a -2.0 V bias voltage enabled efficient energy transfer between the light-emitting and color-changing states, causing clear optical changes. This performance is achieved through fluorescence resonance energy transfer and the inner filter effect, ensuring effective interaction between the components.
The potential applications for this device are vast. It could lead to innovative, energy-efficient displays that are highly visible in both bright and dark environments. For example, this technology could greatly benefit reflective tablets and digital signage, addressing challenges like poor visibility in sunlight and high power consumption in emissive screens.
The device could lead to innovative, energy-efficient displays visible in both bright and dark environments. The team plans to enhance the device with more materials, increasing versatility and opening new commercial applications. Their ultimate goal is to design display technologies that are not only more sustainable but also more versatile.
Journal Reference:
- Rong Cao, Naoto Kobayashi, Kazuki Nakamur and Norihisa Kobayashi. Electrochemically controllable emission and coloration using a modified electrode with a layered clay compound containing viologen derivative and europium(iii) complex†. Journal of Materials Chemistry C. DOI: 10.1039/D4TC04026K
Source: Tech Explorist
