Tunable Luminescence Contrast of Na0.5Bi4.5Ti4O15:Re (Re = Sm, Pr, Er) Photochromics by Controlling the Excitation Energy of Luminescent Centers

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• 作者：Qiwei ZhangYao Zhang ; Haiqin Sun ; Wei Geng ; Xusheng Wang ; Xihong Hao ; Shengli An
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：December 21, 2016
• 年：2016
• 卷：8
• 期：50
• 页码：34581-34589
• 全文大小：609K
• ISSN：1944-8252

文摘

High luminescent switching contrast of photochromic materials is extremely important in improving the sensitivity and resolution of optical switches and high-density optical data storage devices. To date, conventional methods, such as tuning absorption and emission bands based on electron or resonance energy transfer mechanisms in well-known organic photochromic molecules or compounds, have routinely been adopted to tune luminescent switching behavior. However, these strategies and mechanisms are not effectively applied to luminescence switching in inorganic materials because their crystal structures differ strongly from those of organic materials. In this paper, we report a new method to significantly tune the luminescent switching contrast by modifying the excitation energy of luminescent centers in a newly synthesized photochromism material: Na_0.5Bi_4.5Ti₄O₁₅:Re (Re = Sm, Pr, Er). A significant enhancement of luminescence switching contrast was achieved when the luminescent centers were excited by low energy photons at a given irradiation wavelength, intensity, and time, compared with high excitation energy photons. The trend “the lower the excitation energy, the higher the luminescence switching contrast” is universal in different rare earth ion-doped Na_0.5Bi_4.5Ti₄O₁₅ ferroelectrics. The changes in the luminescent switching contrast based on excitation energy are ascribed to nonradiative energy transfer from the luminescent center to the color center by dipole–dipole interactions according to Dexter theory. This possible utilization of excitation energy at lower energy levels is usually less destructive to both information recording and the recording material itself during luminescent readout processes while achieving higher luminescence switching contrast.