Abstract This work reports a new synergistic effect observed in self-sustainable composite films, composed by barium fluoride (BaF2) nanoparticles embedded in polystyrene matrix. Optical absorption measurements were performed in the ultraviolet and visible range. The luminescent properties were investigated by photoluminescence (PL) under excitation in the vacuum ultraviolet region. The PL results showed that self-trapped excitons of BaF2 nanoparticles incorporated into the polymeric matrix are excited at 5.6 eV. This value is 3.4 eV lower than the typical exciton formation energy observed for BaF2 isolated nanoparticles. This phenomenon can be understood as result of a synergistic effect, between polystyrene and BaF2, involving antenna effect and Foster energy transfer. PL lifetime measurements showed that the decay is composed by two main process with short lifetime. From chromatic coordinates of the emitted light it was possible to observe that light emission can be tuned to different shades of colors between blue and green.

中文翻译：

---

BaF2闪烁体-聚苯乙烯复合薄膜在真空紫外辐射下的光致发光特性

摘要 这项工作报告了在自持复合薄膜中观察到的新协同效应，该复合薄膜由嵌入聚苯乙烯基质中的氟化钡 (BaF2) 纳米颗粒组成。在紫外和可见光范围内进行光吸收测量。通过在真空紫外区激发下的光致发光（PL）研究发光特性。PL 结果表明，掺入聚合物基质中的 BaF2 纳米粒子的自陷激子在 5.6 eV 下被激发。该值比观察到的 BaF2 分离纳米粒子的典型激子形成能低 3.4 eV。这种现象可以理解为聚苯乙烯和 BaF2 之间协同效应的结果，涉及天线效应和 Foster 能量转移。PL寿命测量表明，衰变由两个寿命短的主要过程组成。从发射光的色度坐标可以观察到，光发射可以调整为蓝色和绿色之间的不同颜色深浅。