CAJ | 학술논문

用燃烧法制备了平均粒径为10和40 mm的(Y0.96Er0.02)O3纳米晶体样品,并通过1 200℃高温退火获得了同样组分的体材料样品.利用X射线衍射谱(XRD),傅里叶变换红外吸收光谱(FTIR),透射电镜(TEM)和透射电镜(SEM)照片对样品的晶体结构和形貌进行了表征.测量了不同样品980 nm激发下的上转换发射光谱和近红外发射光谱.对实验结果的分析发现,随着粒径的减小,样品发射光谱中红光和近红外发射的成分增加.产生这一现象的原因是由于纳米材料具有比表面积大的特点,能够吸附更多的OH(振动能量3 200～3 800 cm-1),OH-数量的增加使电子从Er3+的4I11/2→I13/2能级(能量差3 600 cm-1)的无辐射弛豫速率增大,这一无辐射弛豫过程减少了4I11/2上的电子布居数,使绿光发射减弱;同时增加了4I13/2上的电子布居数,使红光和近红外发射增强.40 nm样品的1.5 μm发射主峰强度是体材料的1.6倍,这一结果对纳米发光材料的实际应用是很有意义的.
용연소법제비료평균립경위10화40 mm적(Y0.96Er0.02)O3납미정체양품,병통과1 200℃고온퇴화획득료동양조분적체재료양품.이용X사선연사보(XRD),부리협변환홍외흡수광보(FTIR),투사전경(TEM)화투사전경(SEM)조편대양품적정체결구화형모진행료표정.측량료불동양품980 nm격발하적상전환발사광보화근홍외발사광보.대실험결과적분석발현,수착립경적감소,양품발사광보중홍광화근홍외발사적성분증가.산생저일현상적원인시유우납미재료구유비표면적대적특점,능구흡부경다적OH(진동능량3 200～3 800 cm-1),OH-수량적증가사전자종Er3+적4I11/2→I13/2능급(능량차3 600 cm-1)적무복사이예속솔증대,저일무복사이예과정감소료4I11/2상적전자포거수,사록광발사감약;동시증가료4I13/2상적전자포거수,사홍광화근홍외발사증강.40 nm양품적1.5 μm발사주봉강도시체재료적1.6배,저일결과대납미발광재료적실제응용시흔유의의적.
(Y0.96Er0.02Yb0.02)O3 nanocrystals of 10 and 40 nm average particle size were prepared by combustion method.And bulk materials of the same components were obtained by annealing at 1 200 ℃.X-ray diffraction (XRD),Fourier transform infrared (FTLR) spectra,transmission electron microscope (TEM),and scanning electron microscopy (SEM) were used to characterize the crystal structure and morphology of the samples.The upconversion emission spectra and NIR (near-infrared) emission spectra were measured,under 980 nm excitation.The research result indicates that as the particle size decreases,the upconversion red emission and NIR emission components increase in the emission spectra.This phenomenon is attributed to the large ratio of surface area to volume in nanocrystals.This characteristic makes the nanocrystals absorb more OH-,whose vibrational energy is 3 200-3 800 cm-1.The increase in the OH- number enhances the rate of nonradiative relaxation from Er3+4I11/2 to 4I13/2 energy level (energy gap is 3 600 cm-1).This nonradiative relaxation process depopulates the 4I11/2 level and makes the green emission weaker.Meanwhile,this process populates the 4I13/2 level and makes the red and NIR emissions stronger.The intensity of 1.5 μm main peak is 1.6 times that of bulk materials.This result has great significance in actual applications of nanophosphors.