Table 1 Summary of bleaching lifetimes.

From: Prolonged photostability in hexagonal boron nitride quantum emitters

Sample type

Treatment/condition

Bleaching lifetimes (s)

P2 (2.15 eV)

P3 (1.98 eV)

Monolayer CVD

As-prepared

NA

(1) 6.6 ± 0.6

(2) 2.9 ± 0.1, 55 ± 3.2 (87%, 13%)

N2 atmosphere

NA

(1)120 ± 10

(2)5.0 ± 1.1, 150 ± 10 (46%, 54%)

4-layer stack

NA

(1) 110 ± 10

(2) 11 ± 3.9, 150 ± 20 (36%, 64%)

Multilayer CVD

As-prepared

(1) 230 ± 20

(1) 150 ± 10

(2) 11 ± 4.1, 170 ± 20 (33%, 67%)

850 °C in Ar, 30 min

77 ± 74, >2000

(1) 1300 ± 800

(2) 9.4 ± 4.3, > 2000 (38%, 62%)

Multilayer liquid-exfoliated

As-prepared, type-I

NA

(1) 120 ± 10

(2) 10 ± 1.6, 220 ± 30 (53%, 47%)

As-prepared, type-II

>2000

>2000

850 °C in Ar, 30 min

>2000

>2000

  1. P3 (1.98 ± 0.05 eV) and P2 (2.15 ± 0.06 eV) under different conditions, extracted from fitting of overall decay curves of total intensity, with 95% confidence interval. One-exponential model is presented with one lifetime, while two-exponential model is presented with two lifetimes as well as the percentage for each value (i.e., r and 1 - r from Eq. 2). The overall decay curves are presented in Figs. 2, 3d, i, Supplementary Figs. 24, and 25. In as-prepared multilayer samples in the air and monolayer samples under N2 atmosphere, two bleaching lifetimes are observed in each case, which indicates two distinct bleaching mechanisms. The shorter bleaching lifetime is attributed to photochemical reactions with O2, while the red (approximately 5 s) and blue (approximately 10 s) correspond to monolayer and multilayer samples, respectively. The longer 10 s lifetime in multilayer systems could arise from the stabilizing effect of interlayer bonds30. When monolayer hBN is under N2, the 5.0 ± 1.1 s lifetime could be associated with trapped O2 between hBN and the substrate. The consistency of the second bleaching lifetime (approximately 200 s) indicates an intrinsic bleaching mechanism, independent of external environment. The effect of Ar annealing is discussed in the last section of this manuscript.
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