摘要
为改善钛酸铋钠基无铅陶瓷的铁电光伏特性,通过传统固相法制备了B位Mo掺杂的Na_(0.5)Bi_(0.5)(Ti_(1-x)Mo_(x))O_(3)(BNT-Mo_(x),x=0~0.02)无铅铁电陶瓷。通过XRD、拉曼光谱、吸收光谱等测试方法,结合基于密度泛函理论的第一性原理计算,研究了Mo掺杂对BNT陶瓷体系带隙的影响规律及机理。结果表明:随着Mo掺杂量的增加,光学带隙值先减小后增大,当x=1.0%时带隙达到最小值2.33 eV,并且光吸收强度达到最大值69%;通过对能带和态密度计算结果进行分析,发现Mo掺杂BNT体系能带结构由间接带隙转变为直接带隙,出现由Mo的4d轨道所贡献的杂质能级,导致带隙减小。Mo掺杂导致的杂质能级与莫斯-布尔斯坦效应之间存在带隙调控相互竞争关系,可有效调控BNT体系能带结构。
To improve the ferroelectric photovoltaic characteristic of bismuth sodium titanate-based lead-free ceramics.The B-site Mo-doped Na_(0.5)Bi_(0.5)(Ti_(1-x)Mo_(x))O_(3)(BNT-Mo_(x),the value of x is 0 to 0.02)lead-free ferroelectric ceramic was synthesized by the conventional solid state reaction method.The optical band gap of the ceramic was researched by XRD,Raman spectroscopy,absorption spectroscopy,combining the calculations based on first-principles density functional theory(DFT).The experiment results show that with the increase of the content,the optical band gap decreases firstly and then increases.The minimum value of band gap is 2.33 eV when x=1%and the maximum value of light absorption intensity is 69%.The DFT calculation results of the band structure and density of states show that the band gap is shifted from indirect to direct mode by the Mo 4d orbit after the Mo doped,and led to the decrease of band gap.There is a competitive relationship between the impurity energy level caused by Mo doping and the Moss-Bolstein effect in band gap regulation,which could control the band structure of BNT effectively.
作者
谢晓宇
黎清宁
周昌荣
胡朝浩
袁昌来
许积文
XIE Xiaoyu;LI Qingning;ZHOU Changrong;HU Chaohao;YUAN Changlai;XU Jiwen(School of Material Science and Engineering,Guilin University of Electronic Technology,Guilin 541004,China;Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technology,Guilin 541004,China)
出处
《硅酸盐通报》
CAS
北大核心
2021年第9期3098-3104,共7页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(51862004)
广西自然科学基金(2017GXNSFAA198339)
广西电子信息材料构效关系重点实验室基金(172003-Z)。
关键词
钛酸铋钠
第一性原理
光学带隙
能带结构
态密度
sodium bismuth titanate
first-principles
optical band gap
band structure
density of state
