Flexibility of perovskite LED by characterizing mechanical properties of constituent materials

Abstract

Perovskite has been applied to active material of light-emitting diode (LED) due to its advantage such as simple solution based fabrication process, high luminous efficiency, tunable bandgap, and low cost of production. As demand for deformable electronics such as stretchable and flexible display increases, researches of perovskite LEDs progressed on applied in deformable electronics. Since LEDs are manufactured in form of multilayer structure with constituent materials, compressive and tensile stress are different depending on mechanical properties of constituent material and distance from neutral plane under bending stress state. When breakage occurs on constituent materials by stress concentration, a problem occurs in driving device itself. To ensure durability of perovskite LEDs, it is important to analyze critical bending radius using mechanical properties of constituent materials. In this study, we evaluated flexibility of perovskite LEDs using by mechanical properties of constituent materials. Hole-indentation tests were conducted to measure elastic properties of constituent materials suspended over circular hole. Accuracy elastic limit of perovskite, the weakest layer of perovskite LEDs, was measured by uni-axial micro-tensile test. Finally, we analyzed critical bending radius of perovskite LEDs using characterizing mechanical properties of constituent materials with analysis method of stress distribution under bending stress state.