The integration of multifunctionality and efficiency in display technologies has been a longstanding goal. In a recent study published in the journal Nature Electronics, researchers from Sweden and China introduced a novel approach utilizing photo-responsive perovskite light-emitting diodes (PeLEDs) to create a multifunctional display.
a, Schematic process of surface imaging through optical scanning using the multifunctional perovskite display. b,c, Scanned images of a heart shape (b) and enlarged fingerprint drawing (c) (insets show the photographs of the original shapes), where the imaging area is 1.3 × 1.6 cm2. d, The voltage-charging time curve of a supercapacitor when charged with our photo-responsive PeLED working at photovoltaic mode. Inset shows the image of the illuminated devices. e, Voltage attenuation curve of the charged supercapacitor when powering the same PeLEDs. During this process, the voltage of the supercapacitor decreases from ~1.7 to 1.2 V. Inset shows the images of the emissive PeLEDs working at different voltages. Image Credit: https://www.nature.com/articles/s41928-024-01151-x
Current display technologies typically necessitate individual sensors for various functionalities. Additionally, traditionally used displays such as liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays lack photo-responsiveness and struggle to display pixels efficiently. To combat these challenges, this study proposes the use of photo-responsive LEDs based on metal halide perovskite materials as pixels in a multifunctional display.
This innovative approach aims to combine all functionalities within the display pixels themselves, eliminating the need for separate sensors. Leveraging the high photoresponsivity and efficiency of peLEDs, the study envisions a new breakthrough in display technology where displays can offer enhanced capabilities in a slim and lightweight form factor.
Background
The evolution of display technologies has witnessed a shift towards enhancing the capabilities of screens beyond conventional information display. The demand for seamless integration of touch control, ambient light sensing, and fingerprint recognition functionalities within display devices has raised the need for innovative solutions that streamline these features without the need for separate sensors. This drive towards multifunctionality has seen growing research efforts towards exploring advanced materials and device architectures that can enable the direct incorporation of diverse functionalities within individual display pixels.
PeLEDs have emerged as a promising candidate for realizing such multifunctional displays, owing to their high photoresponsivity and efficiency. PeLED-based display technology could eliminate the need for separate sensors such as touch screen, light sensing, image sensing, and photovoltaic functionalities and pave the way for next-generation display technology.
The Current Study
The study highlights the fabrication process of the multifunctional display based on photo-responsive PeLEDs. The fabrication process involved several key steps to create the functional display. Initially, the researchers prepared different layers, including poly(triaryl amine) and CsPb(Br1-xClx)3 perovskite layers, which are essential components of the PeLEDs. These layers were carefully deposited using specific techniques to ensure uniformity and efficiency in light emission.
Subsequently, additional layers such as TPBi, LiF, and Al were deposited under controlled chamber pressures to complete the device structure. The precise deposition of these layers is crucial for optimizing the performance of the PeLEDs, and close attention was also paid to the pixel sizes and display configurations to achieve the desired display characteristics.
Moreover, specific configurations and design considerations were tested for integrating touch control, ambient light sensing, and image sensing functionalities into the PeLED-based display. By carefully engineering the pixel layout and device architecture, the researchers were able to demonstrate the multifunctionality of the display without the need for additional sensors.
Overall, the fabrication process and design considerations were instrumental in creating the multifunctional display based on photo-responsive PeLEDs. The detailed methodology provides insights into the technical aspects of the device fabrication and sets the foundation for the successful implementation of the innovative display technology.
Results and Discussion
The study demonstrates the successful implementation of novel display technology with touch control, ambient light sensing, image sensing, and photovoltaic functionalities integrated into the PeLED pixels. Through a proof-of-concept approach, the researchers show that the display can accurately respond to touch inputs, enabling information input through different touch positions on the screen.
Additionally, the display functions as a self-illuminated image sensor, capturing and reproducing surface images of objects through pixel-by-pixel scanning. The high brightness of the LEDs in display mode and the high photosensitivity in detector mode allow for monitoring photoplethysmography (PPG) signals, showcasing the potential for medical and health monitoring applications.
Furthermore, the study highlights the innovative use of the display for on-screen multi-point fingerprint recognition. By enlarging fingerprint drawings and capturing them using the display, the researchers demonstrate the feasibility of utilizing the display for fingerprint sensing across the entire screen area. This advancement opens new possibilities for enhanced security and access control in electronic devices.
Conclusion
In conclusion, the multifunctional display based on photo-responsive PeLEDs represents a groundbreaking development in display technology. By combining touch control, ambient light sensing, image sensing, and energy conversion capabilities into a single device, the display offers a versatile solution for various electronic applications.
The study's findings pave the way for the development of ultra-thin and lightweight displays with enhanced functionalities, promising potential innovation in display technology. Overall, the study results underscore the potential of photo-responsive perovskite LEDs in revolutionizing display technologies and opening up new possibilities for multifunctional electronic devices.
Journal Reference:
Bao, C., Yuan, Z., Niu, W., Yang, J., et al. A multifunctional display based on photo-responsive perovskite light-emitting diodes. Nature Electronics (2024). https://doi.org/10.1038/s41928-024-01151-x, https://www.nature.com/articles/s41928-024-01151-x