Ghosh Siddhartha, Saha Surajit, Liu Zhiqi, Motapothula M, Patra Abhijeet, Yakovlev Nikolai, Cai Yao, Prakash Saurav, Huang Xiao Hu, Tay Chuan Beng, Cong Chun Xiao, Bhatt Thirumaleshwara, Dolmanan Surani B, Chen Jianqiang, Lü Weiming, Huang Zhen, Tripathy Sudhiranjan, Chua Soo Jin, Yu Ting, Asta Mark, Ariando A, Venkatesan T
NUSNNI-Nanocore, National University of Singapore, 117411, Singapore.
Department of Physics, National University of Singapore, 117542, Singapore.
Sci Rep. 2016 Nov 3;6:36352. doi: 10.1038/srep36352.
In this study we report the existence of novel ultraviolet (UV) and blue emission in rare-earth based perovskite NdGaO (NGO) and the systematic quench of the NGO photoluminescence (PL) by Ce doping. Study of room temperature PL was performed in both single-crystal and polycrystalline NGO (substrates and pellets) respectively. Several NGO pellets were prepared with varying Ce concentration and their room temperature PL was studied using 325 nm laser. It was found that the PL intensity shows a systematic quench with increasing Ce concentration. XPS measurements indicated that nearly 50% of Ce atoms are in the 4+ state. The PL quench was attributed to the novel concept of super hydrogenic dopant (SHD)", where each Ce ion contributes an electron which forms a super hydrogenic atom with an enhanced Bohr radius, due to the large dielectric constant of the host. Based on the critical Ce concentration for complete quenching this SHD radius was estimated to be within a range of 0.85 nm and 1.15 nm whereas the predicted theoretical value of SHD radius for NdGaO3 is ~1.01 nm.
在本研究中，我们报道了基于稀土的钙钛矿钕镓酸盐（NdGaO，简称NGO）中存在新型紫外线（UV）和蓝光发射，以及通过铈（Ce）掺杂对NGO光致发光（PL）的系统猝灭。分别对单晶和多晶NGO（衬底和颗粒）进行了室温PL研究。制备了几种具有不同Ce浓度的NGO颗粒，并使用325 nm激光对其室温PL进行了研究。发现PL强度随着Ce浓度的增加而呈现出系统的猝灭。X射线光电子能谱（XPS）测量表明，近50%的Ce原子处于4 + 价态。PL猝灭归因于“超类氢掺杂剂（SHD）”这一新颖概念，即由于主体的大介电常数，每个Ce离子贡献一个电子，该电子形成一个具有增大玻尔半径的超类氢原子。基于完全猝灭的临界Ce浓度，估计该SHD半径在0.85 nm至1.15 nm范围内，而NdGaO3的SHD半径预测理论值约为1.01 nm。
