Fig. 1: Crystal structure and phosphorescence of AlN SCs. | Nature Communications

Fig. 1: Crystal structure and phosphorescence of AlN SCs.

From: X-ray radiation excited ultralong (>20,000 seconds) intrinsic phosphorescence in aluminum nitride single-crystal scintillators

Fig. 1

a XRD pattern of AlN SC shows obvious characteristic (002) peak (kα 2 peak). The insets show the crystal structure viewed on (110) and (001) faces; N atoms and Al atoms are in orange and blue, respectively. The optical photograph shows a sample of AlN SCs with the diameter of about 15 mm. b Displacement coordinate schematic of phosphorescence emission. Ground state (S0) electrons are excited into singlet excited state (S1) and the electrons in S1 state transit to triplet excited state (T1) by obtaining an intersystem crossing energy of ∆E. The transitions from S1 to S0 usually emit fluorescence (Fluor.) and thermal-active delay fluorescence (TADF), and from T1 to S0 the transitions emit long-living phosphorescence (Phosph.). The phosphorescence spectra of AlN SCs after X-ray excitation for 0 s (c), 3600 s (d), and 7200 s (e) is compared. The insets show corresponding optical photographs collected by a UV-sensitive iCCD detector. f PL intensity plots with decay time show that the time evolution of UV and yellow phosphorescence matches well with exponential decay function.

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