Arunkumar S, Venkataiah G, Marimuthu K
Department of Physics, Gandhigram Rural University, Gandhigram 624 302, India.
Department of Physics, Sri Venkateswara University, Tirupati 517 502, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 5;136 Pt C:1684-97. doi: 10.1016/j.saa.2014.10.067. Epub 2014 Nov 4.
A new series of white light emitting Dy(3+) doped Lead tellurofluoroborate glasses have been prepared and their spectroscopic and energy transfer behavior were explored through analyzing XRD, FTIR, Raman, SEM, EDAX, optical absorption, photoluminescence and lifetime measurements. The fundamental stretching of the various borate and tellurite networks were identified using FTIR and Raman spectral analysis. The bonding parameter studies reveal the ionic nature of the DyO bond in the present glasses. The Judd-Ofelt (JO) intensity parameters determined from the absorption spectra have been used to investigate the nature of bonding and symmetry orientation of the Dy-ligand field environment. The luminescence intensity increases with increasing Dy(3+) ion concentration up to 0.5wt%, beyond that luminescence quenching is observed. The JO parameters have been used to determine the transition probability (A), stimulated emission cross-section (σP(E)), radiative lifetime (τR) and branching ratios (βR) for the different emission transitions from the (4)F9/2 excited level. The higher σP(E) and βR values of the (4)F9/2→(6)H15/2 and (4)F9/2→(6)H13/2 transitions suggest the possible laser action in the visible region. The Y/B ratio, CIE chromaticity color coordinates (x, y) and Color correlated temperature (CCT) were also estimated from the luminescence spectra for different concentration as well as pumping wavelengths. The x, y chromaticity color coordinates fall within the white light region and the white light can be tuned by varying the excitation wavelengths. The lifetime of the (4)F9/2 excited state were measured and is found to decrease with increasing Dy(3+) ion content. The non-exponential behavior is predominant in higher Dy(3+) ion content glasses and is due to the efficient energy transfer between Dy(3+)Dy(3+) ions. The decay curves were fitted to the Inokuti-Hirayama (IH) model to understand the nature of energy transfer. Among the prepared glasses, 0.5DPTFB glass possesses higher A,βR,σP(E),η values and is suggested for lasers and WLED applications.
制备了一系列新型的掺杂Dy(3+)的白色发光碲氟硼酸铅玻璃，并通过XRD、FTIR、拉曼、SEM、EDAX、光吸收、光致发光和寿命测量等手段对其光谱和能量转移行为进行了研究。利用FTIR和拉曼光谱分析确定了各种硼酸盐和碲酸盐网络的基本伸缩振动。键合参数研究揭示了当前玻璃中DyO键的离子性质。由吸收光谱确定的Judd-Ofelt（JO）强度参数用于研究Dy-配体场环境的键合性质和对称取向。发光强度随着Dy(3+)离子浓度增加到0.5wt%而增加，超过该浓度则观察到发光猝灭。JO参数已用于确定从(4)F9/2激发态的不同发射跃迁的跃迁概率（A）、受激发射截面（σP(E)）、辐射寿命（τR）和分支比（βR）。(4)F9/2→(6)H15/2和(4)F9/2→(6)H13/2跃迁的较高σP(E)和βR值表明在可见光区域可能存在激光作用。还从不同浓度以及泵浦波长的发光光谱中估计了Y/B比、CIE色度坐标（x，y）和色坐标温度（CCT）。x，y色度坐标落在白光区域内，并且可以通过改变激发波长来调节白光。测量了(4)F9/2激发态的寿命，发现其随着Dy(3+)离子含量的增加而降低。在较高Dy(3+)离子含量的玻璃中，非指数行为占主导，这是由于Dy(3+) - Dy(3+)离子之间的有效能量转移所致。将衰减曲线拟合到Inokuti-Hirayama（IH）模型以了解能量转移的性质。在所制备的玻璃中，0.5DPTFB玻璃具有较高的A、βR、σP(E)、η值，建议用于激光和白光发光二极管应用。
