%0 Journal Article
%K temperature
%K oxide
%K Perovskite
%K oxides
%K semiconductor
%K chemistry
%K semiconductors
%K semiconductor quantum dots
%K titanium
%K Calcium compounds
%K Perovskite solar cells
%K Stark effect
%K Circularly polarized optical pulse
%K Dielectric confinement
%K Inorganic semiconductors
%K Light-matter coupling
%K Light-matter interactions
%K Perovskite thin films
%K Solution processability
%K Straightforward strategy
%K Semiconductor quantum wells
%K calcium derivative
%K halogen
%K quantum theory
%K thermodynamics
%K Halogens
%A D Giovanni
%A W.K Chong
%A H.A Dewi
%A K Thirumal
%A I Neogi
%A Ramamoorthy Ramesh
%A S Mhaisalkar
%A N Mathews
%A T.C Sum
%B Science Advances
%D 2016
%G eng
%I American Association for the Advancement of Science
%R 10.1126/sciadv.1600477
%T Tunable room-temperature spin-selective optical Stark effect in solution-processed layered halide perovskites
%V 2
%X Ultrafast spin manipulation for opto-spin logic applications requires material systems that have strong spinselective light-matter interaction. Conventional inorganic semiconductor nanostructures [for example, epitaxial II to VI quantum dots and III to V multiple quantum wells (MQWs)] are considered forerunners but encounter challenges such as lattice matching and cryogenic cooling requirements. Two-dimensional halide perovskite semiconductors, combining intrinsic tunable MQW structures and large oscillator strengths with facile solution processability, can offer breakthroughs in this area. We demonstrate novel room-temperature, strong ultrafast spin-selective optical Stark effect in solution-processed (C6H4FC2H4NH3)2PbI4 perovskite thin films. Exciton spin states are selectively tuned by ∼6.3 meV using circularly polarized optical pulses without any external photonic cavity (that is, corresponding to a Rabi energy of ∼55 meV and equivalent to applying a 70 T magnetic field), which is much larger than any conventional system. The facile halide and organic replacement in these perovskites affords control of the dielectric confinement and thus presents a straightforward strategy for tuning light-matter coupling strength. © 2016 The Authors.