10.1021/acs.jpclett.5b00621.s001 Alina M. Schimpf Alina M. Schimpf Jeffrey D. Rinehart Jeffrey D. Rinehart Stefan T. Ochsenbein Stefan T. Ochsenbein Daniel R. Gamelin Daniel R. Gamelin Charge-State Control of Mn<sup>2+</sup> Spin Relaxation Dynamics in Colloidal <i>n</i>‑Type Zn<sub>1–<i>x</i></sub>Mn<sub><i>x</i></sub>O Nanocrystals American Chemical Society 2015 exchange interactions model systems material dynamic future applications technology relaxation rates introduction delocalized charge carriers nanocrystal semiconductor nanostructures conduction band electrons Mn conduction band electron Zn DMS nanostructures relaxation pathway 2015-12-17 08:08:42 Journal contribution https://acs.figshare.com/articles/journal_contribution/Charge_State_Control_of_Mn_sup_2_sup_Spin_Relaxation_Dynamics_in_Colloidal_i_n_i_Type_Zn_sub_1_i_x_i_sub_Mn_sub_i_x_i_sub_O_Nanocrystals/2050425 Colloidal diluted magnetic semiconductor (DMS) nanocrystals are model systems for studying spin effects in semiconductor nanostructures with relevance to future spin-based information processing technologies. The introduction of excess delocalized charge carriers into such nanocrystals turns on strong dopant–carrier magnetic exchange interactions, with important consequences for the physical properties of these materials. Here, we use pulsed electron paramagnetic resonance (pEPR) spectroscopy to probe the effects of excess conduction band electrons on the spin dynamics of colloidal Mn<sup>2+</sup>-doped ZnO nanocrystals. Mn<sup>2+</sup> spin–lattice relaxation is strongly accelerated by the addition of even one conduction band electron per Zn<sub>1–<i>x</i></sub>Mn<sub><i>x</i></sub>O nanocrystal, attributable to the introduction of a new exchange-based Mn<sup>2+</sup> spin relaxation pathway. A kinetic model is used to describe the enhanced relaxation rates, yielding new insights into the spin dynamics and electronic structures of these materials with potential ramifications for future applications of DMS nanostructures in spin-based technologies.