3D Approaches to Stretchable Optoelectronic Devices

Stretchable optoelectronic devices are poised to become important building blocks for future IT applications, whether in the form of expandable screens, body-attachable or wearable devices, or electronics integrated over non-planar objects with arbitrary three-dimensional shapes. In this talk, we will explore the potential of 3D approaches to stretchable OLEDs, which rely on an array of rigid islands coupled with serpentine interconnectors. Specifically, we will address the challenge of increasing the geometrical fill factor (FF), i.e., reducing the area dedicated to serpentine electrodes. In one approach [1], serpentine electrodes are not limited to a 2D plane but act as hinges and stretching interconnectors, significantly improving the initial geometrical FF while allowing for a higher maximum strain. In this design, alternating rigid islands move upward (when compressed toward the initial, zero system-strain state) and downward (when stretched beyond the initial state), while the remaining islands stay fixed to an elastomer. Using this "height-alternant rigid-island architecture," matrix-type stretchable OLEDs with an initial FF of up to 75% and a maximum strain of 45% have been demonstrated. In another approach [2], an ultrathin OLED is affixed to an array of 3D rigid islands, which are supported by an elastomer base. Part of the ultrathin OLED is folded and hidden between adjacent islands in the initial, non-stretched state; as strain is applied, this hidden portion becomes exposed, compensating for the FF loss that would otherwise occur. This method enables a stretchable OLED with an FF maintained above 80% in both the initial and stretched states, with 30% system strain. By individually addressing the hidden active area, we also demonstrate a matrix-type display with a resolution compensation scheme. The overall design methodologies and key considerations for both approaches will be presented.

References
S.-B. Kim et al., Nat. Comm. 15, 7802 (2024).
D. Lee et al., Nat. Comm. 15, 4349 (2024).