MoS2 quantum disks possess dual side light responsive, ultrathin, transparent, and flexible white LED’s.

Figure: White LED

A team of researchers from National Taiwan University, Taipei has demonstrated a dual-side, responsive white LED with ultrathin, transparent, and flexible characteristics based on Graphene Insulator Semiconductor (GIS) structure.

The team achieved this work with 2D nanoflakes such as Molybdenum disulfide (MoS2) quantum disks.

With the advances in the electronics industry, we can expect ultra-thin, flexible, and transparent devices in the upcoming years. And LED technology has a wide range of applications in the electronics industry. But the conventional cannot be utilized for flexible and transparent electronic devices.

And the recent development in white LEDs mostly rely on using toxic-based Cadmium-based quantum dots and lots of challenges are there such as lifetime, toxicity, and high cost.

To overcome the challenges, the research group at National Taiwan University has demonstrated white LEDs based on 2D flakes of molybdenum disulfide (MoS2) the material has high color quality, biocompatibility, and chemical stability.

The team fabricated and demonstrated the device based on a graphene insulator semiconductor structure which is very helpful in combining the superior properties of each constituent material in the device. The device was fabricated using monolayer graphene as a transparent electrode on top of a thin Al2O3 insulating layer deposited on a histidine-doped MoS2 quantum disks layer. Histidine (Env. Friendly dopant) helps to enhance the carriers and improve the carrier transport more rapidly in the electrical conductivity of MoS2 quantum disks.

The GIS device was deposited on patterned indium tin oxide (ITO) coated flexible or glass substrate. Then the device exhibits a white EL spectrum covering the whole visible light region under an external bias. Besides, employing a transparent electrode, dual side emission can be accomplished via GIS-white LED which is very helpful for a range of lighting device applications like full-color displays, indoor illumination, etc. The device fabricated by the team has an excellent performance in the photodetector mode with a fast response time. And, it has multiple functionalities like light emission, photodetection, transparency, flexibility and dual-side emissions. The team claimed that GIS-white LED has great potential in the next generation of optoelectronic devices.

Story Source: https://doi.org/10.1016/j.mtnano.2022.100173