Research on the stability of luminescence of CsPbBr and Mn:CsPbBr PQDs in polar solution.

Mn:CsPbBr PQDs are achieved by hot injection method. As the amount of Mn doping is gradually increased, the photoluminescence (PL) spectra shows a slight blue shift. Mn-doped PQDs exhibit higher quantum efficiency of 83.9% and longer lifetimes of 267 ns. The stability test was performed to assess the susceptibility of the PQDs to polar solutions. It was figured out that although the stabilities of CsPbBr PQDs and Mn-doped PQDs decreased as the polarity of solution increased, Mn-doped PQDs still maintained higher PL intensity than undoped PQD. Notably, 73% PL intensity of Mn:PQDs was maintained which is nearly three times as much as undoped PQDs in water. We found polarity would induce drastic degradation of CsPbBr QDs. The steady-state spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD) verified that CsPbBr QDs tend to aggregate to form larger particles under continuous light soaking. Our work reveals the main origin of instability in CsPbBr QDs and provides reference to engineering such QDs towards optimal device application.