氢掺杂C_(60)薄膜的电导性质研究

本文报道了用微波等离子法制备氢掺杂Ｃ６０薄膜．直流电导测量表明，室温下掺杂的电导率要比未掺杂膜的大５个量级．经５７３Ｋ温度退火后，掺杂膜的电导接近，但仍要高于本征膜的电导率，说明仍有少量的氢留在薄膜中．

直流磁控溅射技术低温制备高电导和高透明的氢掺杂AZO薄膜

采用直流磁控溅射的方法制备掺铝氧化锌(AZO)透明导电薄膜,通过溅射过程中加入氢气的方法来降低AZO薄膜的电阻率。结果表明:通过加入氢气的方法能有效降低AZO薄膜的电阻率;在衬底温度为225℃的低温条件下,通过优化其它沉积参数,制备了电阻率最低为4.5×10^(-4)Ω·cm、可见光区平均透光率在90%的优质AZO薄膜。这说明在溅射过程中引入一定流量的氢气,H可以起到掺杂作用,提高AZO薄膜的电导率。

磁控溅射低温制备高电导高透明氢掺杂薄膜

通过分析直流磁控溅射技术低温制备高电导和高透明的氢掺杂AZO薄膜实验,明确了溅射技术对于低温制备AZO薄膜的重要作用。由此可以证明,引入适量氢气,有利于提升AZO薄膜的电阻率。

添加Fe(C5H5)2合成氢掺杂金刚石大单晶及其表征

在Ni70Mn25Co5-C体系中添加含氢化合物Fe(C5H5)2作为新型氢源,利用温度梯度法,在压力为5.5—6.0 GPa、温度为1280—1400°C的条件下,成功合成出氢掺杂的宝石级金刚石大单晶.通过傅里叶显微红外光谱发现,随着Fe(C5H5)2添加量的增加,合成晶体中与氢相关的对应于sp3杂化C—H键的对称伸缩振动和反对称伸缩振动的红外特征峰2850和2920 cm 1逐渐增强,而晶体中氮含量却逐渐减少.通过合成晶体的拉曼光谱分析发现,金刚石的拉曼峰伴随Fe(C5H5)2的添加向高频偏移,这表明氢的进入在金刚石内部产生了压应力.观察扫描电子显微镜图像发现,在低含量Fe(C5H5)2添加时晶体表面平滑,而高含量添加时晶体表面缺陷增多,且呈现出气孔状.使用新的添加剂Fe(C5H5)2作为氢源,合成出含氢宝石级金刚石单晶,丰富了金刚石单晶中对氢的研究内容,也可为理解天然金刚石的形成机理提供帮助.

高温高压下氮氢协同掺杂对{100}晶面生长宝石级金刚石的影响

在压力为5.5—6.2 GPa,温度为1280—1450℃的条件下,利用温度梯度法详细考察了氮氢协同掺杂对{100}晶面生长宝石级金刚石的影响.实验结果表明伴随合成腔体内氮、氢浓度的升高,合成条件明显升高,金刚石生长V形区间上移;晶体的红外光谱中与氮相关的吸收峰急剧增强,氮含量可达2000 ppm,同时位于2850 cm 1和2920 cm 1对应于sp3杂化C—H键的对称伸缩振动和反对称伸缩振动的红外特征峰逐渐增强,表明晶体中既有高的氮含量,同时又含有氢.对晶体进行电镜扫描发现,氮氢协同掺杂对晶体形貌影响明显,出现拉长的{111}面,且晶体表面上有三角形生长纹理.拉曼测试表明,晶体的峰位向高频偏移、半峰宽变大,说明氮、氢杂质的进入对晶体内部产生了应力.本文成功地以{100}晶面为生长面合成出高氮含氢宝石级金刚石单晶,在探究氮氢共存环境下金刚石生长特性的同时,也可为理解天然金刚石的形成机理提供帮助.

氢气与Cu中间层对GZO薄膜光电性能的影响

采用磁控溅射方法,在H2/Ar混合气氛下制备了GZO薄膜和在Ar气氛下制备了GZO/Cu/GZO多层结构薄膜,分别研究了H2流量和Cu层厚度对薄膜透明导电性能的影响。在此基础上,在H2/Ar混合气氛下制备了GZO/Cu/GZO多层结构薄膜,对Cu层厚度对其性能的影响进行了研究。结果表明,沉积气氛中引入H2能有效降低GZO薄膜的电阻率而提高其透光率,在H2流量为20 sccm时GZO薄膜具有最佳性能。随着Cu厚度的增加,GZO/Cu/GZO多层结构薄膜的电阻率和平均透过率显著下降。在H2/Ar混合气氛下制备的氢化GZO/Cu/GZO多层结构薄膜的电阻率普遍低于Ar气氛下制备的GZO/Cu/GZO多层结构薄膜,但其透光率却随Cu层厚度的增加而显著降低。另外,薄膜的禁带宽度随H2流量的增加而增加,随Cu层厚度的增加而减小。

α-Fe中氢脆现象的第一性原理研究

采用基于密度泛函理论的第一性原理方法,研究了氢原子对α-Fe力学性能的影响,对解析α-Fe氢脆本质做出了新的探索。氢掺杂使α-Fe的晶胞参数、氢原子周围铁原子的电荷以及Fe-H电子重叠数出现了各向异性的变化,从而导致α-Fe内聚力以及塑性各向异性。结果显示:沿[100]方向的内聚力在高氢浓度(HFe4)时明显增大,但其在较小的塑性变形下就达到峰值,随后随塑性变形的增加明显降低,说明氢掺杂使铁塑性降低;沿[001]方向的内聚力逐渐降低,使该方向的断裂韧性降低,导致铁在低应力下产生断裂。根据这些研究结果,认为[100]方向塑性的降低以及[001]方向断裂韧性的降低是导致α-Fe氢脆断裂的主要原因。

H扩散掺杂源漏的自对准顶栅a-IGZO TFT制备工艺研究

采用氢(H)扩散掺杂源漏的方法对自对准顶栅a-IGZO TFT的制备工艺进行了研究。氢的扩散掺杂通过PECVD生长SiNx钝化层而实现。实验结果显示,在栅电极图形化后,是否继续进行栅介质刻蚀对器件性能有较大影响。对刻蚀了SiO_2栅介质层的器件,发现其泄漏电流较大,这可能是由于有源层侧壁的刻蚀残留物导致的;短沟道器件阈值电压偏负且在经过退火后迁移率减小,则是由于严重的H横向扩散导致的。对未刻蚀SiO_2栅介质层的器件,发现其阈值电压相对偏正,应该是因为SiO_2栅介质对H的掺杂有一定的阻挡作用,导致H的横向扩散得到了抑制;器件在经过退火后迁移率上升,开态电流增大,应该是因为未刻蚀栅介质中的H热扩散到下方的源漏区域,降低了源漏电阻。

Self-assembled S-scheme In_(2.77)S_(4)/K^(+)-doped g-C_(3)N_(4)photocatalyst with selective O_(2) reduction pathway for efficient H_(2)O_(2) production using water and air

The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.

分层沉积GaAs/SiO_2纳米薄膜的结构和吸收光谱

应用射频磁控溅射方法分别在抛光硅片和石英玻璃片上分层沉积了GaAs/S iO2纳米薄膜。通过X射线衍射(XRD)、原子力显微镜(AFM)、扫描电子显微镜(SEM)及吸收光谱的测试,发现衬底温度、退火、氢掺杂等制备工艺对分层沉积的GaAs/S iO2纳米薄膜的微观结构和光学性质有明显的影响。本文对相关机理作了探讨。

氮氢共掺杂金刚石中氢的典型红外特征峰的表征

所有天然Ia型金刚石红外光谱中都存在3107 cm-1特征峰,而在金属触媒直接合成的金刚石红外光谱中没有检测出3107 cm-1特征峰.本文在6.3 GPa,1500?C条件下,通过Fe70Ni30触媒中添加P3N5直接合成出具有3107 cm-1特征峰的氮氢共掺杂的金刚石.红外光谱分析表明,合成的金刚石中氢有两种存在形式:一种对应着乙烯基团>C=CH2中C—H键的伸缩振动(3107 cm-1)和弯曲振动(1450 cm-1)的吸收峰,另一种对应着sp3杂化C—H键的对称伸缩振动(2850 cm-1)和反对称伸缩振动(2920 cm-1)的吸收峰.通过分析发现,3107 cm-1吸收峰与金刚石中聚集态的氮原子有关,当金刚石中没有聚集态的氮元素时,即使氮含量高也不会出现3107 cm-1峰;并且2850和2920 cm-1附近的吸收峰比3107 cm-1附近的吸收峰更为普遍存在.这说明sp3杂化C—H键比乙烯基团的C—H键更广泛存在于金刚石中,从两者的峰值看,天然金刚石中的氢杂质主要以乙烯基团>C=CH2存在.3107 cm-1吸收峰与聚集态的氮原子的这种存在关系为天然金刚石形成机制的研究提供了一种新思路,同时较低的合成条件也可能为氢与其他元素共掺杂合成具有n型半导体特性的金刚石提供一个较理想的合成环境.

Preparation and electrochemical performance of nano-scale Ni(OH)_2 doped with zinc

Nano-scale Ni（OH）2 doped with Zn was prepared by precipitation transformation method and characterized by XRD and TEM. The electrochemical performance was investigated by cyclic voltammetry （CV） and constant current technology. The measurement results indicate that the lattice parameters of nano-scale Ni（OH）2 are changed and the agglomeration of particles becomes obvious with the increased Zn-doped content. Compared with un-doped one, the discharge specific capacities ofnano-scale Ni（OH）2 doped with 10% Zn are enhanced by 8% and 6%, respectively, at the discharge rate of 0.2C and 3C. After 110 cycles, the discharge specific capacity of the sample doped with 10% zinc is still above 85% of its initial capacity discharged at 0.2C. Therefore, a suitable Zn-doped content is beneficial to improving the discharge performance of nano-scale Ni（OH）2.

Direct synthesis of nitrogen-doped mesoporous carbons for acetylene hydrochlorination

Nitrogen‐doped ordered mesoporous carbon （N‐OMC） catalysts were directly synthesized using SBA‐15 as a hard template and sucrose as a carbon source. Urea, which was used as the nitrogen source, was carbonized with sucrose. A 3.6 wt% nitrogen doping of the carbon framework was achieved, with more than 70%of the nitrogen incorporated as quaternary nitrogen species. Only 0.2 wt% nitrogen doping, with only 32.7% quaternary nitrogen incorporation was obtained in an N‐OMC catalyst （N‐OMC‐T） prepared using a two‐step post‐synthesis method. The acetylene hy‐drochlorination activities of N‐OMC catalysts prepared via the one‐step method were higher than that of the N‐OMC‐T catalyst because of the higher nitrogen loadings.

无机透明绝热涂料的研制

用掺杂SnO2导电氧化物(TCO)作原料,以无机醇溶透明树脂为成膜物,制备而成的透明绝热涂料,可见光透射率达75%,红外热辐射阻隔率可达72%,隔热效果显著。

掺磷nc-Si∶H薄膜的微结构与光电特性

采用常规射频等离子体增强化学气相沉积方法,以高氢稀释的Si H4为源气体和以PH3为掺杂剂,制备了磷掺杂的氢化纳米晶硅薄膜。结果表明,薄膜的生长速率随PH3/Si H4流量比（Cp）增加而显著减小。Raman谱的研究证实,随Cp增加,薄膜的晶化率经历了先增大后减小的过程,当Cp=1.0%,晶化率达到最大值45.9%。傅里叶变换红外吸收谱测量结果显示,薄膜中的H含量在Cp=2.0%时达到最低值9.5%。光学测量结果表明,本征和掺P的氢化纳米晶硅薄膜在可见光谱范围呈现出良好的光吸收特性,在0.8~3.0 e V范围内,nc-Si（P）∶H薄膜的吸收系数显著大于c-Si。和α-Si∶H薄膜相比,虽然短波范围的吸收系数较低,但是在hν〈1.7 e V区域,nc-Si（P）∶H薄膜的吸收系数要高两到三个量级,显示出优良的红光响应。电学测量表明,适当掺P会显著提高氢化纳米晶硅薄膜的暗电导率,当Cp=0.5%时,薄膜的暗电导率可达5.4 S·cm-1。

Prolonging charge-separation states by doping lanthanide-ions into {001}/{101} facets-coexposed TiO_(2) nanosheets for enhancing photocatalytic H_(2) evolution

Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.

Wheat flour-derived N-doped mesoporous carbon extrudes as an efficient support for Au catalyst in acetylene hydrochlorination

We recently reported an N‐doped mesoporous carbon(N‐MC)extrudate,with major quaternary N species,prepared by a cheap and convenient method through direct carbonization of wheat flour with silica,which has excellent catalytic performance in acetylene hydrochlorination.Herein,we examined the activity of Au supported on N‐MC(Au/N‐MC)and compared it with that of Au supported on nitrogen‐free mesoporous carbon(Au/MC).The acetylene conversion of Au/N‐MC was 50%at 180°C with an acetylene space velocity of 600 h–1 and VHCl/VC2H2 of 1.1,which was double the activity of Au/MC(25%).The introduced nitrogen atoms acted as anchor sites that stabilized the Au3+species and inhibited the reduction of Au3+to Au0 during the preparation of Au/N‐MC catalysts.

In situ synthesis of Fe-N-C catalysts from cellulose for hydrogenation of nitrobenzene to aniline

Owing to Fe being the most abundant and least expensive transition metal on the earth,the utilization of Fe-based catalysts for catalytic hydrogenation has attracted worldwide attention.In this work,a series of N-doped C supported Fe catalysts(Fe-N-C)were prepared by co-pyrolysis of cellulose and ferric chloride under ammonia atmosphere.Characterization methods such as elemental analysis,atomic absorption spectroscopy,nitrogen adsorption-desorption isotherms,transmission electron microscopy,high-resolution transmission electron microscopy,X-ray diffraction,and X-ray photoelectron spectroscopy were carried out to explore the physicochemical properties of the catalysts.Using hydrogenation of nitrobenzene as a model reaction,the catalysts prepared at different pyrolysis temperatures displayed different activities.Fe-N-C-700 exhibited the best activity among these catalysts,with the yield of aniline being up to 98.0%under 5 MPa H2 at 120℃ after 12 h.Combined with the results of catalyst characterization and comparative tests,the transformation of Fe species and the generation of N-doped C,especially graphitized N-doped C,in the catalyst may be the main factors affecting the activity.A kinetic study was carried out and the apparent activation energy was obtained as 31.53 kJ/mol.The stability of the catalyst was also tested and no significant decrease in the activity was observed after 5 runs.

Tuning the oxygen evolution electrocatalysis on NiFe-layered double hydroxides via sulfur doping

We report a facile way to prepare sulfur(S) doped Ni4/5 Fe1/5-layered double hydroxide(LDH) electrocatalysts for oxygen evolution reaction(OER). The influence of S doping amount on the OER activity of the resulted Ni Fe-LDHs was studied and the optimal surface S content was ca. 0.43 at%. The developed S-doped Ni Fe-LDH exhibits excellent OER catalyst activity in 1.0 M KOH with overpotential of only 257 m V at the current density of 10 m A cm^-2. Moreover, the catalyst could maintain high activity after 30 h stability test. The high activity of the S-doped Ni Fe-LDH catalysts may originate from the synergistic effect between S and the Fe sites. This work provides a simple but efficient way to improve the OER performance of transition metal oxides/(oxy)hydroxides.

Hierarchical CoSeS nanostructures assisted by Nb doping for enhanced hydrogen evolution reaction

Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction(HER).Multi-doping and the use of a conductive substrate can further modulate catalytic performance.Herein,Nb-CoSe well dispersed in N-doped carbon nanospheres(NCs,Nb-CoSe@NC)was synthesized to serve as a conductive substrate and facilitated good dispersion of active sites for the HER.Nb doping can also change the electronic structure of CoSe,which facilitates the activity for the HER.In order to further improve the conductivity and intrinsic activity of Nb-CoSe@NC,dual,nonmetal doping was realized through gas sulfurization to prepare hierarchical Nb-CoSeS@NC.The prepared Nb-CoSeS@NC,with a core-shell structure,exhibited a low overpotential of 115 mV at 10 mA cm–2,which is smaller than that of the most doped catalysts.In addition,NCs not only improved the dispersion and conductivity of the catalyst but also prevented metal corrosion in an electrolyte,thus facilitating the long-term stability of Nb-CoSeS@NC.Moreover,the synergistic effect of the multi-doping of Nb,S,and Se was explained.This work provides a promising,multi-doping strategy for the large-scale application of transition-metal-based electrocatalysts for the HER.