Active-Matrix Organic Light-Emitting Diode Display On Human Skin

In a new report on Science Advances, Minwoo Choi and a team of scientists in Electronic Engineering and Materials Science in the Republic of Korea, developed a wearable, full-colour OLED display using a two-dimensional (2-D) material-based backplane transistor. Phys.Org reports: They engineered an 18-by-18 thin-film transistor array on a thin molybdenum disulfide (MoS2) film and transferred it to an aluminium oxide (Al2O3)/polyethylene terephthalate (PET) surface. Choi et al. then deposited red, green and blue OLED pixels on the device surface and observed excellent mechanical and electrical properties of the 2-D material. The surface could drive circuits to control the OLED pixels to form an ultrathin, wearable device. In this work, Choi et al. developed a large-area MoS2 TFT array to operate 324 pixels in a 2-inch RGB OLED, in which the full-color display demonstrated an active-matrix configuration. The RGB OLEDs were made of different optoelectronic characteristics, therefore the team designed the backplane TFTs to control each color pixel. The experimental setup was promising as a wearable display and functioned steadily on human skin without adverse effects. The team used heterogenous material designs to form optoelectronics in the present work. […] The low stiffness of the ultrathin device prevented the deterioration of optical and electrical properties during substantial mechanical deformation reflexes — after its transfer to a human hand. Based on the current-voltage characteristics (I-V), the current level did not change during skin shrinkage or skin stretching exercises and the on-state also did not fluctuate during active-matrix display operation. While the device stability is still in development, the team aim to conduct further engineering to improve the MoS2 film for practical applications as a wearable, full-color AMOLED display.