VO₂ Nanomembrane Materials for Optoelectronics and Robotics

As a typical representative of strongly correlated electron materials, vanadium dioxide (VO₂) nanomembrane materials exhibit insulator-to-metal transition accompanied with crystal structure transformation. The transition can be driven by physical parameters such as temperature, light, electric field, and mechanical strain. Before and after the phase transition, optical and electrical properties of VO₂ nanomembranes will change reversibly. In our research, VO₂ nanomembranes are released from thick substrates and self-assembled into three-dimensional (3D) microstructures, which have reconfigurable shape morphing by multiple stimuli, including thermal, laser and mechanical forces. Such structures have bistable states protected by Gaussian preservation rules with ultrafast deformation speed.¹ Based on 3D VO₂ structures deformation, we demonstrate a smart window to enhance multilevel optical modulation by firstly combining mechanochromism with thermochromism.² A wafer-scale self-rolled-up microtubular bolometer array can be assembled on-chip by releasing pre-strained VO₂ nanomembranes. The self-rolled-up VO₂ nanomembrane microtubes maintain outstanding thermal insulation from the substrate and provide a cavity to trapped incident light, which greatly improves the infrared detection performance of our VO₂ bolometers.³ Furthermore, we are also trying to fabricate some off-chip devices, such as VO₂micro-robots, which realize the controllable movement in multiple environments and will finish various functionalized tasks by combing optical, electrical, and optoelectronic devices.<br/> <br/>[1] Tian, Z., Xu, B., Wan, G., Han, X., Di, Z., Chen, Z. and Mei, Y. Gaussian-preserved, non-volatile shape morphing in three-dimensional microstructures for dual-functional electronic devices. <i>Nat. Commun.</i> 12, 509 (2021).<br/>[2] Li, X., Cao, C., Liu, C., He, W., Wu, K., Wang, Y., Xu, B., Tian, Z., Song, E., Cui, J., Huang, G., Zheng, C., Di, Z., Cao, X. and Mei, Y. Self-rolling of vanadium dioxide nanomembranes for enhanced multi-level solar modulation. <i>Nat. Commun.</i> 13, 7819 (2022).<br/>[3] Wu, B., Zhang, Z., Chen, B., Zheng, Z., You, C., Liu, C., Li, X., Wang, J., Wang, Y., Song, E. Cui, J., An, Z., Huang, G. and Mei, Y. One-step rolling fabrication of VO₂ tubular bolometers with polarization-sensitive and omnidirectional detection. <i>Sci. Adv.</i> doi: 10.1126/sciadv.adi7805 (2023).