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Three-dimensional foldable quantum dot light-emitting diodes


Flexible light-emitting devices that can transform from two-dimensional to three-dimensional (3D) forms could be of use in the development of next-generation displays. Various approaches for converting two-dimensional structures into 3D architectures have been explored, including origami methods that rely on folding along lines in which a structure has been thinned. But the fabrication of foldable 3D light-emitting devices remains challenging due, in particular, to the lack of a practical method for patterning the folding lines. Here we show that 3D foldable quantum dot light-emitting diodes (QLEDs) can be created using laser patterning and metal etch-stop layers with customized ablation thresholds. The approach allows etching to be limited to selected layers of the multilayered QLEDs, and it can be precisely tuned by using alloy-type etch-stop layers. The approach can be used to create QLED architectures with extremely small bending radii (0.047 mm), and we illustrate its capabilities by fabricating a 3D foldable passive matrix array of QLEDs that can display letters and numbers.

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Fig. 1: Three-dimensional folding of ultrathin QLEDs using laser-assisted selective patterning.
Fig. 2: Controlling the etching depth using alloy-type etch-stop layers.
Fig. 3: Bending and folding deformation of the pre-programmed ultrathin QLED.
Fig. 4: Various 3D architectures by folding pre-programmed ultrathin QLEDs.
Fig. 5: Passively driven 8 × 8 foldable QLED array deformed into a curtain-shaped form.
Fig. 6: Dynamic 2D–3D transformation of the foldable PM QLED array.

Data availability

The data files that support the findings of this study are available from the corresponding authors upon reasonable request.

Code availability

We used Arduino 1.8.3 to operate the PM QLEDs. The customized source codes for Arduino are provided in Supplementary Fig. 9.


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This research was supported by IBS-R006-D1 and IBS-R006-A1. This work was also supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (no. 2019R1A5A6099595). J.Y. acknowledges support from Samsung Research Funding & Incubation Center of Samsung Electronics under project no. SRFC-MA2002-03.

Author information




D.C.K., H.Y. and J.K. designed the experiments. D.C.K., H.Y., J.K. and H.S. performed the experiments and analysed the data. J.K., W.S.Y. and J.Y. synthesized and characterized the colloidal quantum dots described in this paper. D.C.K., H.Y. and H.S. made the QLEDs and performed the device characterization. J. H. Kim carried out the FEM calculation. D.C.K., H.Y., J.K., J. H. Koo, T.H. and D.-H.K. wrote the paper. All the authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Taeghwan Hyeon or Dae-Hyeong Kim.

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Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Electronics thanks Yizheng Jin and Yihui Zhang for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Fabrication and pre-programming process of the ultrathin QLED for its 3D controlled folding.

Panels i)-vi) show the step-by-step procedures. Illustrations at the bottom explain the partial etching and the complete etching for the formation of the folding line and the cutting line, respectively. After the selective laser etching, the fabricated QLED is peeled off from the substrate and rotated upside down. Then, by applying a compressive force, the partially-etched folding line can be folded into either a valley-shape or a mountain-shape.

Extended Data Fig. 2 3D surface topography profiles.

3D surface topographies were measured for the laser-etched ultrathin QLED with (1st column) or without (2nd column) the Ag etch-stop layer.

Extended Data Fig. 3 Scanning electron microscope (SEM) images of the folding line in the laser-etched device.

a-b, Front-side (a) and back-side (b) of the laser-etched ultrathin QLED with the Ag etch-stop layer. The folding line was etched under 6 mJ of the laser pulse intensity. In the front-side, the device was etched, while only a crease was formed along the laser-etched line in the back-side. c-d, Front-side (c) and back-side (d) of the laser-etched ultrathin QLED without the Ag etch-stop layer. As the device was completely etched under 4 mJ of the laser pulse intensity, the sample cut by the laser was transferred onto a carbon tape to acquire the SEM images (schematic illustration is shown in the inset).

Extended Data Fig. 4 Captured images from Supplementary Movie 1 that shows the bending and folding deformations of the QLED with the double etch-stop layers.

The device exhibits the outstanding mechanical stability even under mechanical deformations. Also, the foldable QLED is waterproof even after its sharp folding.

Extended Data Fig. 5 Depth-tunable etching with the double etch-stop layers.

a, Schematic illustration that shows the pre-programming condition with the double etch-stop layers to fabricate a 3D architecture with two distinct mountain-shape folds (that is, blunt fold and sharp fold). b, Schematic illustration of the 3D architecture after 3D folding of the pre-programmed ultrathin QLEDs. c-d, Photographs of the front-side (c) and the back-side (d) of the ultrathin QLEDs after the depth-tunable etching. e-f, Photographs of the 3D foldable QLEDs with two distinct mountain-shape folds (e). A magnified view in the red dotted box is shown in (f). Two mountain-shape folds have two different radii of curvature.

Extended Data Fig. 6 Mechanical analysis of the 3D foldable QLED with the double etch-stop layers.

a-c, Strain distributions of the deformed QLEDs (mountain-folded) with the double etch-stop layers, calculated by the FEA. The devices are either unetched (a) or etched by an etching depth of 5 μm (b) or etched by an etching depth of 10 μm (c). The cross-sectional diagrams on the left side exhibit the layered structure of the pre-programmed devices, and the data on the right side show the amount of strain applied to the device during the deformation and the location of the ITO layer and the neutral mechanical plane. In the graph, the thickness of the highlighted region is normalized to be from -1 to 1. The black, red, and blue plot in the graph correspond to the data for the device under the compressive strain of 50% (black line), 70% (red line), and 90% (blue line). In the case of (c), the neutral plane is located near the ITO layer.

Extended Data Fig. 7 Captured images from Supplementary Movie 2 that shows the 3D foldable QLEDs with customized architectures.

The planar QLEDs are pre-programmed with customized patterns of folding and cutting lines for their facile deformation into various 3D architectures. The 3D QLEDs show the stable light-emission performance even after mechanical deformations of folding-unfolding or squeezing, and even under water droplets.

Extended Data Fig. 8 Star-shaped 3D PM QLED array, displaying various image patterns.

a-d, Top view (middle) and side view (right) of the star-shaped PM QLED arrays, which demonstrate various patterns (left).

Extended Data Fig. 9 Captured images from Supplementary Movie 3 that shows the 3D foldable PM QLED array.

The 2D PM QLED array is pre-programmed with customized patterns to form a star-shaped structure. By folding the device along the pre-programmed folding lines, a star-shaped 3D PM QLED array is formed, showing stable light-emission performance during dynamic 2D-3D deformations.

Supplementary information

Supplementary Information  Supplementary Notes 1 and 2 and Figs. 1–10.

Supplementary Video 1

Bending and folding deformations of a pre-programmed QLED with double etch-stop layers.

Supplementary Video 2

Three-dimensional foldable QLEDs with customized architectures.

Supplementary Video 3

Three-dimensional foldable PM QLED array.

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Kim, D.C., Yun, H., Kim, J. et al. Three-dimensional foldable quantum dot light-emitting diodes. Nat Electron 4, 671–680 (2021).

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