Recent developments of flexible InGaZnO thin-film transistors

Flexible InGaZnO thin-film transistors (TFTs) have been extensively investigated over the last decade with an aim to transferring electronic devices from rigid substrates to light-weight, soft and flexible ones. Firstly, an introduction to flexible InGaZnO TFT is provided, where the superiority over its rigid counterparts is illustrated. Then, the TFT structures are exhibited with their primary film layers, and the material choice and process selection are presented for each layer to explain the fabrication of flexible InGaZnO TFTs with high performance. Afterward, the recent advances on the electrical performance of the flexible InGaZnO TFTs achieved by either material optimization or structure innovation are summarized, and their operating principles and improvement mechanisms are clarified. Next, the recent progresses on the mechanical flexibility of flexible InGaZnO TFTs are presented according to improvement methods. All these improvements enable the flexible InGaZnO TFTs to endure smaller bending radius and more bending cycles even under electrical and illumination stresses. In particular, the mechanisms concerning mechanical bending are demonstrated in detail, which successfully explain the bending-induced instability in electrical characteristics of flexible InGaZnO TFTs in numerous studies. Finally, the challenges in this area are summarized as guidance for future research. (© 2021 Wiley‐VCH GmbH)