The energy levels and optical transitions of tetrahedral core/shell InP/ZnSe quantum dots (QDs) are investigated by means of multiband $\mathrm{k}·\mathrm{p}$ theory. Despite the ${\overline{T}}_d$ symmetry relaxing spherical selection rules, the near-band-edge excitonic spectrum is reminiscent of that obtained for spherical nanocrystals. Exceptions appear in large (red-emitting) QDs, where transitions violating the (quasi)angular momentum selection rule ($\mathrm{\Delta }L=0,\pm 2$) are observed, and the ground state does not become dark ($P_{3/2}$-like). Valence band coupling is important in determining the symmetry, degeneracy, and energy of hole states, with split-off holes playing a greater role than in CdSe QDs. The ($1S_e$-like) electron ground state is localized in and around the InP core, far in energy from the excited states, which are more spread into the ZnSe shell. This makes exciton Coulomb interactions be mostly perturbative. Electrons remain largely localized by the InP core even in negative trions, despite electron-electron repulsions. At the same time, the asymmetry between Coulomb attractions and repulsions leads to negative (positive) trions being bound (antibound) by tens of meV. The biexciton binding energy switches from positive to negative, depending on the QD size. The interplay among the different physical factors we examine renders the intrinsic optical response of InP/ZnSe QDs distinct from both core-only InP QDs and conventional II-VI core/shell QDs.

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• Electronic structure
• Excitons
• Luminescence
• Optoelectronics
• Spin-orbit coupling