Interfacial Polarization Mechanism in Image Sticking of Polyimide-Based Flexible OLEDs

Organic light-emitting diodes (OLEDs) have emerged as a critical battleground in display technology due to their self-emissive and foldable properties. However, the adoption of polyimide (PI) as a flexible substrate material introduces technical challenges, particularly image sticking. This study proposes an interfacial polarization mechanism to explain this phenomenon, confirmed through dielectric and ferroelectric spectroscopy. The results show that introducing an amorphous silicon (α-Si) interlayer significantly improves interface compatibility, increasing the polarization response frequency from 74 Hz to 116 Hz and reducing residual polarization strength from 2.81 nC/cm2 to 1.00 nC/cm2. Practical tests on OLED devices demonstrate that the optimized structure (PI/α-Si/SiO2) lowers the image sticking score from 3.46 to 1.67, validating the proposed mechanism. This research provides both theoretical insights and practical solutions for mitigating image sticking in flexible OLED displays.