本文主要研究内容
作者于露（2019）在《窄带隙铁基钙钛矿氧化物的合成及性质研究》一文中研究指出：ABO3钙钛矿结构铁电体是一类重要的功能材料,它结构简单,并且对掺杂表现出相当大的容忍度,A、B位离子不同电子组态提供了多样的化学变换组合以及带来各离子间不同类型的相互作用,诱发丰富的功能特性,因此成为凝聚态物理和多功能材料应用研究的热点之一。近年来,随着科技进步衍生出的环境及能源问题,促使光伏领域备受关注,对铁电体的研究也逐渐延伸到对铁电光伏效应的应用。由于大部分钙钛矿氧化物都是宽带隙的绝缘体,对太阳光谱的利用率较低,这阻碍了铁电太阳能器件光伏效率的提升,因此探索窄带隙铁电体并将其应用于太阳能电池器件具有重要意义。本论文采用理论与实验相结合的研究方法,以BiFeO3(BFO)、Pb(Zr,Ti)O3(PZT)、KNbO3(KNO)、BaTiO3(BTO)等经典铁电体为基础体系,从简单铁基钙钛矿的掺杂改性出发,研究了 A(Fe0.5Nb0.5)O3铁基双钙钦矿的带隙调控行为,并对其构成的固溶体体系结构相变及光电磁等性质作了系统的分析研究,最后用脉冲激光沉积技术制备出高质量Ba(Fe0.5Nb0.5)O3(BFNO)双钙钛矿单晶薄膜,为研发新型高效光伏器件提供了思路。本研究J工作取得的创新性成果包括以下几点:1.采用固相反应法和溶胶-凝胶法分别制备了 Bi0.9Sm0(uFeO3、Bi0.9Sm0.1Fe0.95Mn0.05O3、Bi0.9Sm0.1Fe0.9Mn0.05Ni0.05O3陶瓷和薄膜。研究了 A 位稀土金属元素Sm和B位过渡金属元素Mn、Ni共掺杂对BFO材料的带隙和磁性的影响。同时,在SmFeO3(SFO)中引入Ni元素,制备了 SmFei-xNixN3(SFNO)陶瓷,Ni离子的电荷歧化效应诱导了 SFNO金属性增强。X射线衍射(XRD)数据表明,A位稀土金属Sm和B位过渡金属Mn、Ni共掺杂BFO材料为多晶菱形钙钛矿结构,扫描电子显微镜(SEM)的测试分析显示,陶瓷样品中出现的液相是导致晶粒异常长大的主要原因;薄膜样品的表面平整、光滑、致密。采用Williamson-Hall(W-H)分析法估算薄膜内应力,结果表明Sm/Mn/Ni的引入导致内应力增加,诱发晶格畸变。陶瓷和薄膜样品的光学带隙(E在)均因过渡金属离子的掺杂发生了不同程度的窄化。Mn的掺杂引入了带间半满态;Ni 3d轨道没有出现在原价带顶上方,而是与O2p相互作用,抬高了 O 2p轨道位置,实现了带隙窄化。从薄膜的磁滞回线可以看出,随着过渡金属元素的掺杂BFO基材料的铁磁性增强,其主要原因是掺杂引起的晶格内应力导致晶格畸变,破坏了螺旋反铁磁结构,从而使BFO基材料表现出宏观铁磁性。具有正交结构的稀土铁氧体SFO陶瓷有较大的烧结温区,通过漫反射光谱估算出其光学带隙为2.06 eV。在SFO中引入Ni元素导致晶格收缩和晶粒细化,漫反射光谱表明SFNO在可见光和近红外光波段的光吸收明显增强,Ni离子的电荷歧化行为影响了 SFO带隙,使SFNO金属性增强,带隙减小。2.Pb(Zr0.53Ti0.47)O3-Pb(Feo.5M0.5)O3(M=Nb/Ta,PZTFN/IPZTFT)陶瓷的相变及光电磁性质研究。在晶体结构研究的基础上,对PZTFN/PZTFT材料的窄带隙和室温铁电性能进行了表征分析,同时发现铁磁有序也存在于该材料体系中,这使其在光伏器件和磁电存储等领域具有潜在的应用价值。将双钙钛矿 Pb(Fe0.5Nb0.5)O3(PFN)和 Pb(Fe0.5Ta0.5)O3引入 Pb(Zr0.53Ti0.47)O3制备了 PZTFN/PZTFT固溶体体系。微结构表征显示所有PZTFN/PZTFT均为纯相ABO3结构,结晶性良好且表现出四方相到立方相的结构相变。利用拉曼光谱对局部对称性分析发现,高浓度组分样品具有偏离立方相的局部赝立方晶体结构。PZTFN/PZTFT的光学带隙较PZT有明显减小,PFN的E&仅为2.08 eV。以PZT的第一性原理计算为基础,分析了其能带结构,导带底位置的降低可能是PZTFN/PZTFT带隙减小的主要原因,Fe离子的掺杂引入带尾态进入禁带,降低了 PZT的光学带隙。另外,受晶粒大小的影响,同组分浓度下PZTFT的光学带隙略小于PZTFN。四方结构的0.1PZTFN不仅表现出较好的铁电性,同时也具有室温铁磁性,Fe离子的局域自旋极化电子和传导电子间发生交换相互作用是导致铁磁性出现的主要原因,随着掺杂浓度的增加,铁磁性转变为顺磁性。然而,PZTFT并没有表现出宏观铁磁性,这暗示了非磁性离子Nb5+和Ta5+在相互作用中起到了一定的作用,晶格结构和内应力影响了非磁性离子和磁性离子间的交换相互作用,从而导致宏观磁性的不同表达。3.制备了KNbO3-Ba(Feo.5Nbo.5)O3(KBFNO)无铅复合陶瓷材料,详细研究了该体系的结构相变,并发现其可调控窄带隙、铁电和铁磁有序。另外,利用低容许因子材料Bi(Zn0.5Ti0.5)O3(BZT)诱导BaTiO3发生结构相变,分析了Bi(Zn0.5Ti0.5)O3-BaTiO3(BBZTO)的晶体结构对光学性质的影响。借助于XRD、拉曼光谱表征手段研究了 KBFNO从正交相Amm2到立方相Pm3m的结构相变行为,KBFNO陶瓷的布拉格衍射峰被索引为钙钛矿结构,拉曼光谱分析发现其局部组分波动现象和立方对称性局部降低的晶体结构。SEM显示晶粒形貌从层状结构到不规则球形的连续变化。BFNO的引入可使KNO带隙大幅度降低,对于KBFNO陶瓷,其Eg最低值为1.15 eV,带隙值和组分x的非线性关系符合光学弯曲效应,遵从公式Eg=3.21-5.65x+ 4.17x2。这种带隙变化主要是由离子掺杂引起的结构弛豫和电荷交换造成的。具有化学d0态的Nb5+产生的二阶Jahn-Teller扭转引发了自发极化,使BFNO表现出室温铁电性。从磁滞回线可以看出,在KNO中引入BFNO后,KBFNO材料发生了从抗磁性到铁磁性的转变,可以用束缚磁极化子理论来解释这一现象。采用低容许因子的BZT对高容许因子BTO进行掺杂,诱导BBZTO从四方相转变为菱方相,其准同型相界在x = 0.06附近。用W-H法分析了晶格应力,结果显示替代离子进入了 BTO主晶格,形成内应力场导致了晶格畸变。BBZTO的带隙值随着BZT的掺杂先减小后逐渐增大,四方相八面体场静电排斥作用造成Zn3d轨道分裂,引起了带隙结构的改变,这是带隙减小的主要原因,随着掺杂量的增加,结构相变又促使带隙宽化。在ABO3-A(B’B")O3的无铅体系中,KBFNO有望打破铁电体光伏效率的限制,在铁电光伏领域具有极大的应用潜力。4.采用脉冲激光沉积技术在SrTiO3(STO)单晶衬底上生长BFNO单晶薄膜,优化了其制备工艺,研究了影响薄膜质量的主要因素。从理论和实验两方面证实了BFNO为具有铁电、铁磁有序和高介电常数的窄带隙铁电体。第一性原理计算结果表明BFNO的光学禁带宽度为1.6 eV,电子跃迁主要为从被占据的O 2p到未被占据的Fe 3d态的电荷转移,以及导带和价带Fe 3d态之间的d-d跃迁。在实验范围内的最优条件下所制备的BFNO单晶薄膜表面平整致密,沿STO衬底表面的c轴方向外延生长。BFNO薄膜的磁滞回线表现出S型滞后曲线,制备过程中产生的氧空位作为一个F中心俘获电子,成为两个相邻的Fe3+的媒介形成束缚极化子,构成铁磁交换作用,随着衬底温度的升高,氧空位减少,因此,在650(℃衬底温度下制备的样品较700℃具有更强的铁磁性。以Au作为顶电极,Nb:STO作为底电极,制备了Au/BFNO/Nb:STO三明治结构器件,并对BFNO的铁电性和介电性进行了表征。从实验角度证实了BFNO薄膜具有铁电性。另外,BFNO也表现出较大的介电常数,介电常数随频率的升高而减小。
Abstract
ABO3gai tai kuang jie gou tie dian ti shi yi lei chong yao de gong neng cai liao ,ta jie gou jian chan ,bing ju dui can za biao xian chu xiang dang da de rong ren du ,A、Bwei li zi bu tong dian zi zu tai di gong le duo yang de hua xue bian huan zu ge yi ji dai lai ge li zi jian bu tong lei xing de xiang hu zuo yong ,you fa feng fu de gong neng te xing ,yin ci cheng wei ning ju tai wu li he duo gong neng cai liao ying yong yan jiu de re dian zhi yi 。jin nian lai ,sui zhao ke ji jin bu yan sheng chu de huan jing ji neng yuan wen ti ,cu shi guang fu ling yu bei shou guan zhu ,dui tie dian ti de yan jiu ye zhu jian yan shen dao dui tie dian guang fu xiao ying de ying yong 。you yu da bu fen gai tai kuang yang hua wu dou shi kuan dai xi de jue yuan ti ,dui tai yang guang pu de li yong lv jiao di ,zhe zu ai le tie dian tai yang neng qi jian guang fu xiao lv de di sheng ,yin ci tan suo zhai dai xi tie dian ti bing jiang ji ying yong yu tai yang neng dian chi qi jian ju you chong yao yi yi 。ben lun wen cai yong li lun yu shi yan xiang jie ge de yan jiu fang fa ,yi BiFeO3(BFO)、Pb(Zr,Ti)O3(PZT)、KNbO3(KNO)、BaTiO3(BTO)deng jing dian tie dian ti wei ji chu ti ji ,cong jian chan tie ji gai tai kuang de can za gai xing chu fa ,yan jiu le A(Fe0.5Nb0.5)O3tie ji shuang gai qin kuang de dai xi diao kong hang wei ,bing dui ji gou cheng de gu rong ti ti ji jie gou xiang bian ji guang dian ci deng xing zhi zuo le ji tong de fen xi yan jiu ,zui hou yong mai chong ji guang chen ji ji shu zhi bei chu gao zhi liang Ba(Fe0.5Nb0.5)O3(BFNO)shuang gai tai kuang chan jing bao mo ,wei yan fa xin xing gao xiao guang fu qi jian di gong le sai lu 。ben yan jiu Jgong zuo qu de de chuang xin xing cheng guo bao gua yi xia ji dian :1.cai yong gu xiang fan ying fa he rong jiao -ning jiao fa fen bie zhi bei le Bi0.9Sm0(uFeO3、Bi0.9Sm0.1Fe0.95Mn0.05O3、Bi0.9Sm0.1Fe0.9Mn0.05Ni0.05O3tao ci he bao mo 。yan jiu le A wei xi tu jin shu yuan su Smhe Bwei guo du jin shu yuan su Mn、Nigong can za dui BFOcai liao de dai xi he ci xing de ying xiang 。tong shi ,zai SmFeO3(SFO)zhong yin ru Niyuan su ,zhi bei le SmFei-xNixN3(SFNO)tao ci ,Nili zi de dian he qi hua xiao ying you dao le SFNOjin shu xing zeng jiang 。Xshe xian yan she (XRD)shu ju biao ming ,Awei xi tu jin shu Smhe Bwei guo du jin shu Mn、Nigong can za BFOcai liao wei duo jing ling xing gai tai kuang jie gou ,sao miao dian zi xian wei jing (SEM)de ce shi fen xi xian shi ,tao ci yang pin zhong chu xian de ye xiang shi dao zhi jing li yi chang chang da de zhu yao yuan yin ;bao mo yang pin de biao mian ping zheng 、guang hua 、zhi mi 。cai yong Williamson-Hall(W-H)fen xi fa gu suan bao mo nei ying li ,jie guo biao ming Sm/Mn/Nide yin ru dao zhi nei ying li zeng jia ,you fa jing ge ji bian 。tao ci he bao mo yang pin de guang xue dai xi (Ezai )jun yin guo du jin shu li zi de can za fa sheng le bu tong cheng du de zhai hua 。Mnde can za yin ru le dai jian ban man tai ;Ni 3dgui dao mei you chu xian zai yuan jia dai ding shang fang ,er shi yu O2pxiang hu zuo yong ,tai gao le O 2pgui dao wei zhi ,shi xian le dai xi zhai hua 。cong bao mo de ci zhi hui xian ke yi kan chu ,sui zhao guo du jin shu yuan su de can za BFOji cai liao de tie ci xing zeng jiang ,ji zhu yao yuan yin shi can za yin qi de jing ge nei ying li dao zhi jing ge ji bian ,po huai le luo xuan fan tie ci jie gou ,cong er shi BFOji cai liao biao xian chu hong guan tie ci xing 。ju you zheng jiao jie gou de xi tu tie yang ti SFOtao ci you jiao da de shao jie wen ou ,tong guo man fan she guang pu gu suan chu ji guang xue dai xi wei 2.06 eV。zai SFOzhong yin ru Niyuan su dao zhi jing ge shou su he jing li xi hua ,man fan she guang pu biao ming SFNOzai ke jian guang he jin gong wai guang bo duan de guang xi shou ming xian zeng jiang ,Nili zi de dian he qi hua hang wei ying xiang le SFOdai xi ,shi SFNOjin shu xing zeng jiang ,dai xi jian xiao 。2.Pb(Zr0.53Ti0.47)O3-Pb(Feo.5M0.5)O3(M=Nb/Ta,PZTFN/IPZTFT)tao ci de xiang bian ji guang dian ci xing zhi yan jiu 。zai jing ti jie gou yan jiu de ji chu shang ,dui PZTFN/PZTFTcai liao de zhai dai xi he shi wen tie dian xing neng jin hang le biao zheng fen xi ,tong shi fa xian tie ci you xu ye cun zai yu gai cai liao ti ji zhong ,zhe shi ji zai guang fu qi jian he ci dian cun chu deng ling yu ju you qian zai de ying yong jia zhi 。jiang shuang gai tai kuang Pb(Fe0.5Nb0.5)O3(PFN)he Pb(Fe0.5Ta0.5)O3yin ru Pb(Zr0.53Ti0.47)O3zhi bei le PZTFN/PZTFTgu rong ti ti ji 。wei jie gou biao zheng xian shi suo you PZTFN/PZTFTjun wei chun xiang ABO3jie gou ,jie jing xing liang hao ju biao xian chu si fang xiang dao li fang xiang de jie gou xiang bian 。li yong la man guang pu dui ju bu dui chen xing fen xi fa xian ,gao nong du zu fen yang pin ju you pian li li fang xiang de ju bu yan li fang jing ti jie gou 。PZTFN/PZTFTde guang xue dai xi jiao PZTyou ming xian jian xiao ,PFNde E&jin wei 2.08 eV。yi PZTde di yi xing yuan li ji suan wei ji chu ,fen xi le ji neng dai jie gou ,dao dai de wei zhi de jiang di ke neng shi PZTFN/PZTFTdai xi jian xiao de zhu yao yuan yin ,Feli zi de can za yin ru dai wei tai jin ru jin dai ,jiang di le PZTde guang xue dai xi 。ling wai ,shou jing li da xiao de ying xiang ,tong zu fen nong du xia PZTFTde guang xue dai xi lve xiao yu PZTFN。si fang jie gou de 0.1PZTFNbu jin biao xian chu jiao hao de tie dian xing ,tong shi ye ju you shi wen tie ci xing ,Feli zi de ju yu zi xuan ji hua dian zi he chuan dao dian zi jian fa sheng jiao huan xiang hu zuo yong shi dao zhi tie ci xing chu xian de zhu yao yuan yin ,sui zhao can za nong du de zeng jia ,tie ci xing zhuai bian wei shun ci xing 。ran er ,PZTFTbing mei you biao xian chu hong guan tie ci xing ,zhe an shi le fei ci xing li zi Nb5+he Ta5+zai xiang hu zuo yong zhong qi dao le yi ding de zuo yong ,jing ge jie gou he nei ying li ying xiang le fei ci xing li zi he ci xing li zi jian de jiao huan xiang hu zuo yong ,cong er dao zhi hong guan ci xing de bu tong biao da 。3.zhi bei le KNbO3-Ba(Feo.5Nbo.5)O3(KBFNO)mo qian fu ge tao ci cai liao ,xiang xi yan jiu le gai ti ji de jie gou xiang bian ,bing fa xian ji ke diao kong zhai dai xi 、tie dian he tie ci you xu 。ling wai ,li yong di rong hu yin zi cai liao Bi(Zn0.5Ti0.5)O3(BZT)you dao BaTiO3fa sheng jie gou xiang bian ,fen xi le Bi(Zn0.5Ti0.5)O3-BaTiO3(BBZTO)de jing ti jie gou dui guang xue xing zhi de ying xiang 。jie zhu yu XRD、la man guang pu biao zheng shou duan yan jiu le KBFNOcong zheng jiao xiang Amm2dao li fang xiang Pm3mde jie gou xiang bian hang wei ,KBFNOtao ci de bu la ge yan she feng bei suo yin wei gai tai kuang jie gou ,la man guang pu fen xi fa xian ji ju bu zu fen bo dong xian xiang he li fang dui chen xing ju bu jiang di de jing ti jie gou 。SEMxian shi jing li xing mao cong ceng zhuang jie gou dao bu gui ze qiu xing de lian xu bian hua 。BFNOde yin ru ke shi KNOdai xi da fu du jiang di ,dui yu KBFNOtao ci ,ji Egzui di zhi wei 1.15 eV,dai xi zhi he zu fen xde fei xian xing guan ji fu ge guang xue wan qu xiao ying ,zun cong gong shi Eg=3.21-5.65x+ 4.17x2。zhe chong dai xi bian hua zhu yao shi you li zi can za yin qi de jie gou chi yu he dian he jiao huan zao cheng de 。ju you hua xue d0tai de Nb5+chan sheng de er jie Jahn-Tellerniu zhuai yin fa le zi fa ji hua ,shi BFNObiao xian chu shi wen tie dian xing 。cong ci zhi hui xian ke yi kan chu ,zai KNOzhong yin ru BFNOhou ,KBFNOcai liao fa sheng le cong kang ci xing dao tie ci xing de zhuai bian ,ke yi yong shu fu ci ji hua zi li lun lai jie shi zhe yi xian xiang 。cai yong di rong hu yin zi de BZTdui gao rong hu yin zi BTOjin hang can za ,you dao BBZTOcong si fang xiang zhuai bian wei ling fang xiang ,ji zhun tong xing xiang jie zai x = 0.06fu jin 。yong W-Hfa fen xi le jing ge ying li ,jie guo xian shi ti dai li zi jin ru le BTOzhu jing ge ,xing cheng nei ying li chang dao zhi le jing ge ji bian 。BBZTOde dai xi zhi sui zhao BZTde can za xian jian xiao hou zhu jian zeng da ,si fang xiang ba mian ti chang jing dian pai chi zuo yong zao cheng Zn3dgui dao fen lie ,yin qi le dai xi jie gou de gai bian ,zhe shi dai xi jian xiao de zhu yao yuan yin ,sui zhao can za liang de zeng jia ,jie gou xiang bian you cu shi dai xi kuan hua 。zai ABO3-A(B’B")O3de mo qian ti ji zhong ,KBFNOyou wang da po tie dian ti guang fu xiao lv de xian zhi ,zai tie dian guang fu ling yu ju you ji da de ying yong qian li 。4.cai yong mai chong ji guang chen ji ji shu zai SrTiO3(STO)chan jing chen de shang sheng chang BFNOchan jing bao mo ,you hua le ji zhi bei gong yi ,yan jiu le ying xiang bao mo zhi liang de zhu yao yin su 。cong li lun he shi yan liang fang mian zheng shi le BFNOwei ju you tie dian 、tie ci you xu he gao jie dian chang shu de zhai dai xi tie dian ti 。di yi xing yuan li ji suan jie guo biao ming BFNOde guang xue jin dai kuan du wei 1.6 eV,dian zi yue qian zhu yao wei cong bei zhan ju de O 2pdao wei bei zhan ju de Fe 3dtai de dian he zhuai yi ,yi ji dao dai he jia dai Fe 3dtai zhi jian de d-dyue qian 。zai shi yan fan wei nei de zui you tiao jian xia suo zhi bei de BFNOchan jing bao mo biao mian ping zheng zhi mi ,yan STOchen de biao mian de czhou fang xiang wai yan sheng chang 。BFNObao mo de ci zhi hui xian biao xian chu Sxing zhi hou qu xian ,zhi bei guo cheng zhong chan sheng de yang kong wei zuo wei yi ge Fzhong xin fu huo dian zi ,cheng wei liang ge xiang lin de Fe3+de mei jie xing cheng shu fu ji hua zi ,gou cheng tie ci jiao huan zuo yong ,sui zhao chen de wen du de sheng gao ,yang kong wei jian shao ,yin ci ,zai 650(℃chen de wen du xia zhi bei de yang pin jiao 700℃ju you geng jiang de tie ci xing 。yi Auzuo wei ding dian ji ,Nb:STOzuo wei de dian ji ,zhi bei le Au/BFNO/Nb:STOsan ming zhi jie gou qi jian ,bing dui BFNOde tie dian xing he jie dian xing jin hang le biao zheng 。cong shi yan jiao du zheng shi le BFNObao mo ju you tie dian xing 。ling wai ,BFNOye biao xian chu jiao da de jie dian chang shu ,jie dian chang shu sui pin lv de sheng gao er jian xiao 。
论文参考文献
论文详细介绍
论文作者分别是来自华东师范大学的于露，发表于刊物华东师范大学2019-07-02论文，是一篇关于钙钛矿论文,相变论文,铁电光伏效应论文,光学带隙论文,铁磁性论文,华东师范大学2019-07-02论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自华东师范大学2019-07-02论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：钙钛矿论文; 相变论文; 铁电光伏效应论文; 光学带隙论文; 铁磁性论文; 华东师范大学2019-07-02论文;