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利用基于密度泛函理论的第一性原理计算Pt、N单掺杂及Pt-N不同位置共掺杂闪锌矿ZnS的晶型结构、电荷布局、电子结构以及光学性质.计算结果表明,Pt单掺杂后晶格体积增大,N单掺杂后的晶格体积减小,Pt-N共掺杂时的相对位置不同,晶格参数及电荷布局均存在差异,从而对体系的畸变产生不同影响.形成能计算表明Pt、N非邻位共掺杂相对于邻位共掺杂体系更易实现.电子结构计算结果表明,Pt掺杂ZnS后使材料表现出了一定的金属属性;共掺杂体系中,随着Pt-N距离的增大,N-2p轨道与Zn-3d在价带深能级的局域化作用减弱,价带部分的N-2p轨道逐渐聚集于费米能级附近形成杂质能级,有助于光生电子的跃迁,提高光催化效率.光学性质计算结果表明,共掺杂Pt-N间距离越大,低能区的介电常数虚部ε_2的峰值越大,在可见光区的吸收峰值也越大. 相似文献
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Jintao Hong 《中国物理 B》2021,30(8):87801-087801
Optoelectronic properties of MoSe2 are modulated by controlled annealing in air. Characterizations by Raman spectroscopy and XPS demonstrate the introduction of oxygen defects. Considerable increase in electron and hole mobilities reveals the highly improved electron and hole transport. Furthermore, the photocurrent is enhanced by nearly four orders of magnitudes under 7 nW laser exposure after annealing. The remarkable enhancement in the photoresponse is attributed to an increase in hole trapping centers and a reduction in resistance. Furthermore, the annealed photodetector shows a fast time response on the order of 10 ms and responsivity of 3×104 A/W. 相似文献
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通过研究不同种类钯催化剂[Pd(dppf)2Cl2,Pd(OAc)2,Pd(PPh3)4]、碱(Na2CO3,Na HCO3,K2CO3,K3PO4,Cs2CO3,Cs F)、溶剂(DME/H2O,DMF/H2O,Dioxane/H2O)及温度(70,80,100℃)对5-溴-3-叔丁基水杨醛与吡啶-4-硼酸制备5-(4-吡啶)-3-叔丁基水杨醛化合物的Suzuki偶联反应的影响,开发出一种高效催化吸或供电子基取代的芳基硼酸与吸电子基取代的溴代芳烃的偶联反应的方法,该反应在Pd(PPh3)4,K2CO3,Dioxane/H2O(V∶V=4∶1)、80℃的条件下产率达到97%,且具有分离简单、重现性好的特征;但对供电子基取代的溴代芳烃参与的反应催化效果一般. 相似文献
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Fabrication of CoFe_2O_4 ferrite nanowire arrays in porous silicon template and their local magnetic properties
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CoFe_2O_4 ferrite nanowire arrays are fabricated in porous silicon templates. The porous silicon templates are prepared via metal-assisted chemical etching with gold(Au) nanoparticles as the catalyst. Subsequently, CoFe_2O_4 ferrite nanowires are successfully synthesized into porous silicon templates by the sol–gel method. The magnetic hysteresis loop of nanowire array shows an isotropic feature of magnetic properties. The coercivity and squareness ratio(M_r/M_s) of ensemble nanowires are found to be 630 Oe(1 Oe = 79.5775 A·m~(-1) and 0.4 respectively. However, the first-order reversal curve(FORC) is adopted to reveal the probability density function of local magnetostatic properties(i.e., interwire interaction field and coercivity). The FORC diagram shows an obvious distribution feature for interaction field and coercivity. The local coercivity with a value of about 1000 Oe is found to have the highest probability. 相似文献