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作为一种稳定性好、抗辐射能力强、原材料丰富的宽禁带半导体，ZnO在光催化的研究领域中成为热点材料，但是其仅能吸收可见光中的紫光，因此如何扩大ZnO对可见光的响应范围是一个值得研究的问题.掺杂改性是解决这个问题的常用方法.基于以上考量，本文应用第一性原理计算方法研究了N与Pr掺杂对ZnO的电子结构和光学性质的影响.研究结果表明：共掺体系比单掺体系更容易形成，且共掺体系的稳定性随Pr浓度的增加先增强后变弱；同一体系的最短Zn–O键与最长Zn–O键的布居数比例随杂质浓度的增大先增大后减小，说明杂质的掺入对体系的晶格畸变有很大的影响，有利于光生空穴-电子对的分离，从而提高材料的光催化活性.N 2p态与Pr 4f态发生杂化对晶体的完整性产生了破坏，在杂质原子周围形成晶场，造成能级劈裂，带隙减小；介电函数虚部的主峰位均向低能区域移动，吸收光谱中各掺杂体系发生红移，各共掺体系随着杂质原子Pr浓度的增加，在可见光区的响应范围依次扩大，吸收能力也依次增加，说明N与Pr的共掺杂对提高ZnO的光催化性是有利的.ZnO is a wide bandgap semiconductor with the advantages of good stability, strong radiation resistance, and low cost. It has become a hot material in the field of photocatalysis, but it can only absorb purple light. Therefore, it is a valuable problem to study how to expand the response range of ZnO to visible light. Doping modification is a common method to solve this problem. In order to carry out the relevant research, the calculation in this paper are carried out by the CASTEP tool in Materials Studio software based on the first-principles of ultrasoft pseudopotential of density functional theory, the geometric structures of ZnO, Zn0.875Pr0.125O, ZnO0.875N0.125, Zn0.875Pr0.125O0.875N0.125, Zn0.75Pr0.25O0.875N0.125, Zn0.625Pr0.375O0.875N0.125 are constructed. All the models are based on the optimization of the geometry structure. By using the method of generalized gradient approximation plus U, we calculate the band structure, density of states, population, absorption spectra and dielectric functions of the models. The results show Co-doped system is easier to form than single-doped system, and the stability of the co-doped system increases first and then decreases with the increase of Pr concentration. The population ratio of the shortest Zn-O bond to the longest Zn-O bond in the same system increases first and then decreases with the impurity concentration, which shows that the doping of impurities has a great influence on the lattice distortion of the system, and the distortion is benefit for the separation of photogenerated hole-electron pairs. Therefore, the photocatalytic activity of the materials can be improved. Hybridization of N-2p and Pr-4f states destroys the integrity of crystals and forms crystal fields around impurity atoms, which results in splitting of energy levels and narrowing of bandgap. Compared with intrinsic ZnO, the static dielectric constant of all doped systems increases, especially the constant of Pr-N co-doped systems increases with the increase of doped Pr concentration, which indicates that the polarization ability of the co-doped systems increases with the increase of doped Pr atomic concentration. The main peaks of the dielectric function imaginary part of the doping systems move to the low energy region, and the absorption spectrums are red-shifted. As the concentration of impurity Pr atom increases, in the visible region, the absorption capacity of each co-doped system increases, their response range is enlarged in turn, showing the co-doping of N and Pr is benefit for improving the photocatalytic activity of ZnO.
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Keywords:
- electronic structure /
- optical properties /
- ZnO
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[20] Clark S J, Segall M D, Pickard C J, Hasnip P J, Probert M J, Refson K, Payne M C 2005 Zeitschrift fuer Kristallographie 220 567
[21] Segall M D, Lindan P J D, Probert M J, Pickard C J, Hasnip P J, Clark S J, Payne M C 2002 J. Phys.: Condens. Mat. 14 2717
[22] Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865
[23] Pickett W E, Erwin S C, Ethridge E C 1998 Phys. Rev. B 58 1201
[24] Jia X F, Hou Q Y, Xu Z C, Qu L F 2018 J. Magn. Magn. Mater. 465 128
[25] Janotti A, van der Walle C G 2007 Phys. Rev. B 76 165202
[26] Feng J, Xiao B, Wan C L, Qu Z X, Huang Z C, Chen J C, Zhou R, Pan W 2011 Acta Mater. 59 1742
[27] Guo S, Hou Q, Xu Z, Zhao C 2016 Physica B 503 93
[28] Li P, Deng S, Zhang L, Li Y, Yu J, Liu D 2010 Chinese J. Chem. Phys. 23 527
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[1] Moon S C, Matsumura Y, Kitano M, Matsuoka M, Anpo M 2003 Res. Chem. Intermediat. 29 233
[2] Zhou C, Lai C, Zhang C, Zeng G, Huang D, Cheng M, Hu L, Xiong W P, Chen M, Wang J J, Yang Y, Jiang L B 2018 Appl. Catal. B: Environ. 238 6
[3] Zou J J, Chen C, Liu C J, Zhang Y P, Han Y, Cui L 2005 Mater. Lett. 59 3437
[4] Fons P, Tampo H, Niki S, Kolobov A V, Ohkubo M, Tominaga J, Friedrich S, Carboni R, Boscherini F 2006 Nuclear Inst. & Methods in Physics Research B 246 75
[5] Belaidi A, Dittrich T, Kieven D, Tornow J, Schwarzburg K, Kunst M, Allsop N, Lux-Steiner M C, Gavrilov S 2009 Sol. Energ. Mat. Sol. C. 93 1033
[6] Krunks M, Katerski A, Dedova T, Acik I O, Mere A 2008 Sol. Energ. Mat. Sol. C. 92 1016
[7] Look D C 2001 Mater. Sci. Eng. B 80 383
[8] Rout C S, Krishna S H, Vivekchand S R C, Govindaraj A, Rao C N R 2006 Chem. Phys. Lett. 418 586
[9] Zhang J M, Gao D, Xu K W 2012 Sci. China: Phys. Mech. 55 428
[10] Lan W, Liu Y, Zhang M, Wang B, Yan H, Wang Y 2007 Mater. Lett. 61 2262
[11] Li Y, Zhao X, Fan W 2015 J. Phys. Chem. C 115 3552
[12] Yao Y, Cao Q 2013 Acta Metall. Sin: Engl. 26 467
[13] Yu Y S, Kim G Y, Min B H, Kim S C 2004 J. Eur. Ceram. Soc. 24 1865
[14] Zhang J M, Chen Z, Zhong K, Xu G, Huang Z 2014 Sci. Bull. 59 3232
[15] Persson C, Platzerbjörkman C, Malmström J, Törndahl T, Edoff M 2006 Phys. Rev. Lett. 97 146403
[16] Salah N, Hameed A, Aslam M, Abdel-Wahab M S, Babkair S S, Bahabri F S 2016 Chem. Eng. J. 291 115
[17] Sharma S, Mehta S K, Kansal S K 2016 J. Alloy. Compd. 699 323
[18] Chen L L, Lu J G, Ye Z Z, Lin Y M, Zhao B H, Ye Y M, Li J S, Zhu L P 2005 Appl. Phys. Lett. 87 2939
[19] Chen J L, Devi N, Li N, Fu D J, Ke X W 2018 Chin. Phys. B 27 397
[20] Clark S J, Segall M D, Pickard C J, Hasnip P J, Probert M J, Refson K, Payne M C 2005 Zeitschrift fuer Kristallographie 220 567
[21] Segall M D, Lindan P J D, Probert M J, Pickard C J, Hasnip P J, Clark S J, Payne M C 2002 J. Phys.: Condens. Mat. 14 2717
[22] Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865
[23] Pickett W E, Erwin S C, Ethridge E C 1998 Phys. Rev. B 58 1201
[24] Jia X F, Hou Q Y, Xu Z C, Qu L F 2018 J. Magn. Magn. Mater. 465 128
[25] Janotti A, van der Walle C G 2007 Phys. Rev. B 76 165202
[26] Feng J, Xiao B, Wan C L, Qu Z X, Huang Z C, Chen J C, Zhou R, Pan W 2011 Acta Mater. 59 1742
[27] Guo S, Hou Q, Xu Z, Zhao C 2016 Physica B 503 93
[28] Li P, Deng S, Zhang L, Li Y, Yu J, Liu D 2010 Chinese J. Chem. Phys. 23 527
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