Blue Transparent OLEDs with High Stability and Transmittance for Modulating Sleep Disorders

Optoelectronics devices utilizing organic light-emitting diodes (OLEDs) are emerging as new platforms for healthcare applications. In particular, wearable optoelectronics such as visual stimulus systems offer a distinctive advantage to intervene in and improve sleep disorders. In this study, two improvements are proposed for transparent OLEDs (TrOLEDs) that will be critical for visual applications. First, zinc sulfide with high surface energy and a high refractive index is explored as a seed and capping layer. An ultra-thin silver cathode of 8 nm is demonstrated to be feasible in TrOLEDs, and luminous transmittance of 91% is achieved. Second, in general, achieving the operational stability of TrOLEDs with high transmittance is challenging due to the vulnerability of thin electrodes. By introducing a doping process to the electron transport layer, a lifetime comparable to that of control OLEDs with thick cathodes (>90%) is secured. Last, a preclinical model using blue light is proposed to modulate sleep patterns. Melanopsin is stimulated at the highest level of sleep desire, reducing non-rapid eye movement sleep duration in mice by up to 14%. Based on these results, the proposed TrOLEDs are promising candidates for modulating sleep disorders such as insomnia and narcolepsy-cataplexy with the convenience of wearable form factors.

Automated summary

Optoelectronics devices utilizing OLEDs are promising platforms for healthcare applications, particularly wearable visual stimulus systems for sleep disorder intervention. This study proposes two improvements for TrOLEDs, including a high refractive index zinc sulfide layer and an ultra-thin silver cathode, achieving a luminous transmittance of 91%. By introducing a doping process to the electron transport layer, TrOLEDs with high transmittance can achieve a lifetime comparable to control OLEDs. A preclinical model using blue light is suggested to modulate sleep patterns, showing a reduction in non-rapid-eye-movement sleep duration in mice. These TrOLEDs offer convenience and potential for modulating sleep disorders such as insomnia and narcolepsy-cataplexy.