RT Journal Article
SR Electronic
T1 Excitons in 2D perovskites for ultrafast terahertz photonic devices
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP eaax8821
DO 10.1126/sciadv.aax8821
VO 6
IS 8
A1 Kumar, Abhishek
A1 Solanki, Ankur
A1 Manjappa, Manukumara
A1 Ramesh, Sankaran
A1 Srivastava, Yogesh Kumar
A1 Agarwal, Piyush
A1 Sum, Tze Chien
A1 Singh, Ranjan
YR 2020
UL http://advances.sciencemag.org/content/6/8/eaax8821.abstract
AB In recent years, two-dimensional (2D) Ruddlesden-Popper perovskites have emerged as promising candidates for environmentally stable solar cells, highly efficient light-emitting diodes, and resistive memory devices. The remarkable existence of self-assembled quantum well (QW) structures in solution-processed 2D perovskites offers a diverse range of optoelectronic properties, which remain largely unexplored. Here, we experimentally observe ultrafast relaxation of free carriers in 20 ps due to the quantum confinement of free carriers in a self-assembled QW structures that form excitons. Furthermore, hybridizing the 2D perovskites with metamaterials on a rigid and a flexible substrate enables modulation of terahertz fields at 50-GHz modulating speed, which is the fastest for a solution-processed semiconductor-based photonic device. Hence, an exciton-based ultrafast response of 2D perovskites opens up large avenues for a wide range of scalable dynamic photonic devices with potential applications in flexible photonics, ultrafast wavefront control, and short-range wireless terahertz communications.