Abstract We report time-resolved second-order fluorescence between Stark levels of 1D2 and 3H4 in Pr3+:YPO4 nanocrystals with different crystal phase. Both intensity ratios of transition peaks between Stark levels and fluorescence lifetimes are modulated by phase composition and dressing effect. We have found that the maximum excitation peak shifts from yellow to orange-red region with continuous phase transformation from hexagonal phase to tetragonal phase, which is attributed to different multi-phonon relaxation rate induced by O–H group in hexagonal phase. The fluorescence lifetimes and intensity ratios of splitting peaks in time domain have also been effectively modulated by choosing excitation frequencies to resonate with different Stark levels. Both wavelength and time tunable luminescence has potential applications in biological labeling, imaging and solid state display devices.

中文翻译：

---

不同晶相的 Pr3+:YPO4 纳米晶体 Stark 能级之间的可调发光

摘要 我们报告了具有不同晶相的 Pr3+:YPO4 纳米晶体中 1D2 和 3H4 斯塔克能级之间的时间分辨二阶荧光。Stark 能级和荧光寿命之间的跃迁峰强度比均受相组成和修整效应的调节。我们发现最大激发峰从黄色到橙红色区域随着从六方相到四方相的连续相转变，这是由于六方相中 O-H 基团引起​​的多声子弛豫率不同。通过选择激发频率以与不同的斯塔克能级共振，时域中分裂峰的荧光寿命和强度比也得到了有效调制。波长和时间可调的发光在生物标记中都有潜在的应用，