Matryoshka-inspired continuous assembly of flexible silicon microribbons and photodetectors via selective transfer printing

Silicon microribbon (SiMR), as an intermediate structure format between silicon nanowire and silicon nanomembrane, is of great interest to serve as the functional material for flexible electronics, which represents an unusual electronic platform with widespread applications and promising future. However, the scalable production of SiMRs and/or devices on flexible substrates, in a deterministic assembly manner, still faces significant challenges. Herein, inspired by the matryoshka doll, referring to a set of dolls with decreased size and placed one inside another, we develop a universal and convenient approach to continuously and deterministically assemble flexible SiMRs and electronic devices through the selective transfer printing technique. By optimizing and repeating the selective transfer printing, continuous assembly of flexible SiMRs and devices are realized. Both theoretical calculation and simulation are performed to analyze the influence of the utilized viscoelastic stamp on the adhesive energy with SiMR, thus providing guidance for optimizing the design of stamp microstructure and enhancing the transfer efficiency of SiMRs. Finally, matryoshka-like flexible photodetectors, as an example, are fabricated by utilizing the sequentially prepared SiMRs via the proposed approach. This matryoshka-inspired assembly approach can be extended to prepare other functional semiconducting microribbons or devices in high controllability and yield, thus implying a promising future in the field of flexible electronics.