Robust shell passivation of CdSe colloidal quantum dots to stabilize radioluminescence emission

Systematic characterization of semiconductor colloidal quantum dots (cQDs) response to ionizing radiation must be performed to use them in radiation detection. In this study, the robustness of multi-shell (MS) and core/shell (CS) cQDs was investigated under irradiation. Radioluminescence (RL) measurements with kV and MV photon beams revealed a better resistance of MS cQDs to ionizing radiation, with their spectra fluctuating by barely ∼ 1 nm. A systematic signal recovery between subsequent irradiations was noticed for MS cQDs only. A beam energy dependence of the RL stability was detected between kV and MV energies. At the same point of dose cumulated, the RL signal loss for the kV beams was observed to be ∼6-7% smaller than that of the MV beam, for both types of cQDs. These results demonstrate that MS cQDs are better candidates as ionizing radiation sensors than CS cQDs, especially in the kV energy range.