Rational Codoping as a Strategy to Improve Optical Properties of Doped Semiconductor Quantum Dots

Doping is a powerful and convenient technique for rationally altering the electronic, magnetic, and optical properties of materials including nanomaterials such as quantum dots (QDs) or nanocrystals (NCs). Most doping involves introduction of an impurity element or ion, into the crystal lattice of the host material, which tends to result in lattice distortion and/or charge imbalance when the dopant charge does not match the charge of the host ion replaced. One solution to such problems is codoping with another element or ion that helps to reduce lattice distortion or charge imbalance, which can stabilize the primary dopant in the host lattice and substantially improve the photoluminescence (PL) of the primary dopant. Furthermore, interaction between the codopant and primary dopant can be used to tune the PL properties by altering energy levels related to donor-acceptor pair recombination.