Joly A G, Chen W, Roark J, Zhang J Z
Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA.
J Nanosci Nanotechnol. 2001 Sep;1(3):295-301. doi: 10.1166/jnn.2001.049.
The photoluminescence (excited at both 300 nm and 383.5 nm) and up-conversion luminescence (excited at 767 nm) of the Mn2+ 4T1-->6A1 transition in both bulk and ZnS:Mn2+ nanoparticles have been measured as a function of temperature. The Mn2+ emission spectra shift monotonically to longer wavelengths at lower temperatures, whereas the intensity change of the luminescence is more complex. The complicated temperature behavior is explained by considering the processes of nonradiation relaxation via phonon coupling, exciton thermal dissociation (binding energy), energy transfer, carrier trapping, and the temperature change of the absorption spectra. The fact that the temperature dependence of the 767 nm excited up-conversion luminescence is the same as the 383.5 nm excited photoluminescence in both bulk and nanoparticles supports the conclusion that the up-conversion luminescence is due to two-photon absorption.
已测量了块状和ZnS:Mn²⁺纳米颗粒中Mn²⁺从⁴T₁跃迁到⁶A₁的光致发光（在300 nm和383.5 nm处激发）和上转换发光（在767 nm处激发）随温度的变化。Mn²⁺发射光谱在较低温度下单调地向更长波长移动，而发光强度变化更为复杂。通过考虑声子耦合的非辐射弛豫过程、激子热解离（结合能）、能量转移、载流子俘获以及吸收光谱的温度变化来解释这种复杂的温度行为。在块状材料和纳米颗粒中，767 nm激发的上转换发光与383.5 nm激发的光致发光的温度依赖性相同，这一事实支持了上转换发光是由双光子吸收引起的结论。
