This study utilized cellulose-based external light extraction films to enhance the outcoupling efficiency of organic light-emitting diodes (OLEDs). These films were created through a straightforward fabrication employing the biopolymers hydroxyethyl cellulose (HEC) and tannic acid (TA). We observed that the hydrogen bonding between HEC and TA could spontaneously generate a random micr... https://www.alarecre.com/NHL-Dallas-Stars-Black-Background-iPhone-13-Pro-Max-MagSafe-Case-p96318/