Nonlinear absorption and photoluminescence of CuCl crystallites under size quantization of excitons

Abstract

Excitonic processes in CuCl nanospheres of mean radius ranging from 20 to 150 Å embedded in a glass matrix are investigated. Specific features resulting from quantum confinement are analyzed. Exciton-exciton interaction and relaxing the k -selection rule lead to size-dependent linear and nonlinear optical properties resulting in the light-induced blue shift of excitonic bands, slowing down of radiative decay and drastic changes in the excitation and relaxation dynamics of excitons confined in a quantum box. In addition to the standard classification of the weak (Δ E exc ⪡ Ry ∗) and the strong (Δ E exc > Ry ∗) confinement regime, the peculiarities of the range in which E LO ⩽ Δ E exc ⪡ Ry ∗ are discussed.