QD/2D Hybrid Nanoscrolls: A New Class of Materials for High-Performance Polarized Photodetection and Ultralow Threshold Laser Action.

Ghosh, Rapti; Lin, Hung-I; Chen, Yu-Siang; Singh, Mukesh; Yen, Zhi-Long; Chiu, Shengkuei; Lin, Hsia-Yu; Bera, Krishna P; Liao, Yu-Ming; Hofmann, Mario; Hsieh, Ya-Ping; Chen, Yang-Fang

Nanoscrolls are a class of nanostructures where atomic layers of 2D materials are stacked consecutively in a coaxial manner to form a 1D spiral topography. Self-assembly of chemical vapor deposition grown 2D WS2 monolayer into quasi-1D van der Waals scroll structure instigates a plethora of unique physiochemical properties significantly different from its 2D counterparts. The physical properties of such nanoscrolls can be greatly manipulated upon hybridizing them with high-quantum-yield colloidal quantum dots, forming 0D/2D structures. The efficient dissociation of excitons at the heterojunctions of QD/2D hybridized nanoscrolls exhibits a 3000-fold increased photosensitivity compared to the pristine 2D-material-based nanoscroll. The synergistic effects of confined geometry and efficient QD scatterers produce a nanocavity with multiple feedback loops, resulting in coherent lasing action with an unprecedentedly low lasing threshold. Predominant localization of the excitons along the circumference of this helical scroll results in a 12-fold brighter emission for the parallel-polarized transition compared to the perpendicular one, as confirmed by finite-difference time-domain simulation. The versatility of hybridized nanoscrolls and their unique properties opens up a powerful route for not-yet-realized devices toward practical applications.