Parallel-Stacked Flexible Organic Light-Emitting Diodes for Wearable Photodynamic Therapeutics and Color-Tunable Optoelectronics

Abstract

Deformable organic light-emitting diode (OLED) based optoelectronic devices hold promise for various wearable applications including biomedical systems and displays, but current OLED technologies require high voltage and lack the power needed for wearable photodynamic therapy (PDT) applications and wearable displays. This paper presents a parallel-stacked OLED (PAOLED) with high power, more than 100 mW/cm 2 , at low voltage (<8 V). The current dispersion ratio can be tuned by optimizing the structure of the individual OLEDs stacked to create the PAOLED, allowing control of the PAOLED's wavelength shapes, current efficiency, and power. In this study, a fabricated PAOLED operated reliably for 100 h at a high power of 35 mW/cm 2 . Confirming its potential application to PDT, the measured singlet oxygen generation ratio of the PAOLED was found to be 3.8 times higher than the reference OLED. The high-power PAOLED achieved a 24% reduction in melanoma cancer cell viability after a short (0.5 h) irradiation. In addition, a white light PAOLED with color tuning was realized through OLED color combination, and a high brightness of over 30 000 cd/m 2 was realized, below 8.5 V. In conclusion, the PAOLED was demonstrated to be suitable for a variety of low-voltage, high-power wearable optoelectronic applications.

22‐4: Invited Paper: OLEDs for Wearables: From Form Factor Engineering to Healthcare Applications

“…Newborn babies often go through blue-light therapy for prevention of jaundice, for example. Phototherapies may be classified into the following: (i) photobiomodulation (PBM), which is to use lowintensity light to modulate cellular function; (ii) photothermal treatment, which is to use light to induce thermal ablation of cells to be treated; and (iii) photodynamic therapy (PDT), which employs light to activate photosensitizer to produce reactive oxygen species (ROS) to attack malignant cells [6].…”

“…Recently, Jeon et al has explored the feasibility of OLEDs for PDT [6]. It was shown that high-intensity illumination is far more effective in creation of ROS.…”

P‐66: A Bilayer Encapsulation with High Chemical Stability in Harsh Environments for Environmentally Robust OLEDs

“…With the ongoing development of the Internet of Things (IoT), organic light emitting diodes (OLEDs) are being utilized in a wide range of platforms including wearable displays, automotive displays, and see-through displays due to their attractive properties such as high transparency, low power consumption, light weight, and outstanding deformability. (1)(2)(3)(4)(5)(6)(7) However, such applications expose OLEDs to various environmental factors such as high temperature/humidity or rainy weather. Despite this, the reliability of OLEDs has not been characterized yet under harsh conditions.…”

Emerging Biomedical Applications of Organic Light‐Emitting Diodes

“…d,e) Stacked red-emitting OLEDs with parallel connection of subunits reaching high power output and improved device lifetime. Reproduced with permission [144]. Copyright 2020, American Chemical Society.…”

“…This can attack nearby cells. Reproduced with permission [144]. Copyright 2020, American Chemical Society.…”