Light-induced Kondo-like exciton-spin interaction in neodymium(II) doped hybrid perovskite.

Tuning the properties of a pair of entangled electron and hole in a light-induced exciton is a fundamentally intriguing inquiry for quantum science. Here, using semiconducting hybrid perovskite as an exploratory platform, we discover that Nd-doped CHNHPbI (MAPbI) perovskite exhibits a Kondo-like exciton-spin interaction under cryogenic and photoexcitation conditions. The feedback to such interaction between excitons in perovskite and the localized spins in Nd is observed as notably prolonged carrier lifetimes measured by time-resolved photoluminescence, ~10 times to that of pristine MAPbI without Nd dopant. From a mechanistic standpoint, such extended charge separation states are the consequence of the trap state enabled by the antiferromagnetic exchange interaction between the light-induced exciton and the localized 4 f spins of the Nd in the proximity. Importantly, this Kondo-like exciton-spin interaction can be modulated by either increasing Nd doping concentration that enhances the coupling between the exciton and Nd 4 f spins as evidenced by elongated carrier lifetime, or by using an external magnetic field that can nullify the spin-dependent exchange interaction therein due to the unified orientations of Nd spin angular momentum, thereby leading to exciton recombination at the dynamics comparable to pristine MAPbI.