A series of Er3+/Yb3+ co-doped Sb2O3-WO3-Li2O glasses were prepared. Intense green upconversion fluorescence was observed near 524 and 544nm under excitation at 980 nm. The upconversion process was proved to be a two-...A series of Er3+/Yb3+ co-doped Sb2O3-WO3-Li2O glasses were prepared. Intense green upconversion fluorescence was observed near 524 and 544nm under excitation at 980 nm. The upconversion process was proved to be a two-photon absorption process. The upconversion fluorescence efficiency was enhanced by increasing introduction concentration of Yb3+ ions. The low maximum phonon energy of the glasses indicated that the glasses were good potential for upconversion optical devices.展开更多
Metal nitrides are widely studied due to their outstanding physical properties, including high hardness,high thermal and chemical stability, low electrical resistivity etc. Generally, metal nitrides can be obtained fr...Metal nitrides are widely studied due to their outstanding physical properties, including high hardness,high thermal and chemical stability, low electrical resistivity etc. Generally, metal nitrides can be obtained from the direct reaction of metal and ammonia/nitrogen. However, some of the metal nitrides,such as Ta_3N_5, cannot be synthesized by direct nitridation of metals. To achieve Ta_3N_5, high-oxidationstate Ta precursors like Ta_2O_5, NaTaO_3, TaS_3, K_6Ta_(10.8)O_(30), Ta(N(CH_3)_2)_5 and TaCl_5 have to be employed,which is a time-consuming and laborious process with the possibility of introducing undesirable impurities. Here taking Ta_3N_5 as an example, a facile carbonate-assisted one-step nitridation method is proposed, which enables the direct synthesis of high-oxidation-state metal nitride films from metal precursors under ammonia flow. The mechanism of the nitridation process has been studied, which carbon dioxide released from carbonates decomposition reacts with metallic Ta and assists the one-step conversion of metallic Ta to Ta_3N_5. The as-prepared Ta_3N_5 film, after modified with NiFe layered double hydroxide, exhibits promising water splitting performance and stability. This method avoids the preoxidation process of metal precursors in high-oxidation-state metal nitride synthesis, and may facilitate the direct fabrication of other important metal nitrides besides Ta_3N_5.展开更多
CuWO_4和CuMoO_4的固溶体CuW_(1-x)Mo_xO_4是一种铜基多组分氧化物半导体,拥有比CuWO_4更窄的带隙.理论上,它可以拓宽对太阳光谱的响应范围,吸收更大部分的可见光,获得更高的太阳能-化学能转换效率.本研究通过简单、低成本的喷雾热裂解...CuWO_4和CuMoO_4的固溶体CuW_(1-x)Mo_xO_4是一种铜基多组分氧化物半导体,拥有比CuWO_4更窄的带隙.理论上,它可以拓宽对太阳光谱的响应范围,吸收更大部分的可见光,获得更高的太阳能-化学能转换效率.本研究通过简单、低成本的喷雾热裂解法在导电玻璃上制备了CuW_(1-x)Mo_xO_4薄膜光阳极.在AM 1.5G模拟太阳光(100 m W cm^(-2))照射下,制备出的CuW_(1-x)Mo_xO_4光阳极在pH 7的0.1 mol L^(-1)磷酸缓冲液中产生了比CuWO_4光阳极更高的光电流.结合IPCE和莫特-肖特基分析可知,光电流的增长来源于Mo原子的加入所造成的光子利用率的提高以及载流子浓度的增加.而且,在最优的Mo/W原子比例下,1.23 V_(RHE)偏压时的光电流从0.07 m A cm^(-2)显著地增加到0.46 m A cm^(-2).与对应的颗粒组装薄膜光阳极(通过固相反应结合涂覆-粘结后处理得以制备)相比较,喷雾热裂解法所制备的光阳极有利于降低电阻和促进电荷传输.展开更多
The synthesis of perovskite oxynitrides,which are promising photoanode candidates for solar energy conversion,is normally accomplished by high-temperature ammonolysis of oxides and carbonate precursors,thus making the...The synthesis of perovskite oxynitrides,which are promising photoanode candidates for solar energy conversion,is normally accomplished by high-temperature ammonolysis of oxides and carbonate precursors,thus making the deposition of their planar films onto conductive substrates challenging.Here,we proposed a facile strategy to prepare a series of perovskite oxynitride films.Taking SrTaO_(2)N as a prototype,we prepared SrTaO_(2)N films on Ta foils under NH_(3) flow by utilizing the vaporized SrCl_(2)/SrCO_(3) eutectic salt.The SrTaO_(2)N films exhibit solar water-splitting photocurrents of 3.0 mA cm^(-2) at 1.23 V vs.RHE(reversible hydrogen electrode),which increases by 270%compared to the highest photocurrent(1.1 mA cm^(-2) at 1.23 V vs.RHE)of SrTaO_(2)N reported in the literature.This strategy may also be applied to directly prepare a series of perovskite oxynitride films on conductive substrates such as ATaO_(2)N(A=Ca,Ba)and ANbO_(2)N(A=Sr,Ba).展开更多
文摘A series of Er3+/Yb3+ co-doped Sb2O3-WO3-Li2O glasses were prepared. Intense green upconversion fluorescence was observed near 524 and 544nm under excitation at 980 nm. The upconversion process was proved to be a two-photon absorption process. The upconversion fluorescence efficiency was enhanced by increasing introduction concentration of Yb3+ ions. The low maximum phonon energy of the glasses indicated that the glasses were good potential for upconversion optical devices.
基金supported by the National Natural Science Foundation of China (U1663228 and 21473090)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Metal nitrides are widely studied due to their outstanding physical properties, including high hardness,high thermal and chemical stability, low electrical resistivity etc. Generally, metal nitrides can be obtained from the direct reaction of metal and ammonia/nitrogen. However, some of the metal nitrides,such as Ta_3N_5, cannot be synthesized by direct nitridation of metals. To achieve Ta_3N_5, high-oxidationstate Ta precursors like Ta_2O_5, NaTaO_3, TaS_3, K_6Ta_(10.8)O_(30), Ta(N(CH_3)_2)_5 and TaCl_5 have to be employed,which is a time-consuming and laborious process with the possibility of introducing undesirable impurities. Here taking Ta_3N_5 as an example, a facile carbonate-assisted one-step nitridation method is proposed, which enables the direct synthesis of high-oxidation-state metal nitride films from metal precursors under ammonia flow. The mechanism of the nitridation process has been studied, which carbon dioxide released from carbonates decomposition reacts with metallic Ta and assists the one-step conversion of metallic Ta to Ta_3N_5. The as-prepared Ta_3N_5 film, after modified with NiFe layered double hydroxide, exhibits promising water splitting performance and stability. This method avoids the preoxidation process of metal precursors in high-oxidation-state metal nitride synthesis, and may facilitate the direct fabrication of other important metal nitrides besides Ta_3N_5.
基金supported by the National Basic Research Program of China (973 Program, 2013CB632404)National Natural Science Foundation of China (21473090 and 51272102)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘CuWO_4和CuMoO_4的固溶体CuW_(1-x)Mo_xO_4是一种铜基多组分氧化物半导体,拥有比CuWO_4更窄的带隙.理论上,它可以拓宽对太阳光谱的响应范围,吸收更大部分的可见光,获得更高的太阳能-化学能转换效率.本研究通过简单、低成本的喷雾热裂解法在导电玻璃上制备了CuW_(1-x)Mo_xO_4薄膜光阳极.在AM 1.5G模拟太阳光(100 m W cm^(-2))照射下,制备出的CuW_(1-x)Mo_xO_4光阳极在pH 7的0.1 mol L^(-1)磷酸缓冲液中产生了比CuWO_4光阳极更高的光电流.结合IPCE和莫特-肖特基分析可知,光电流的增长来源于Mo原子的加入所造成的光子利用率的提高以及载流子浓度的增加.而且,在最优的Mo/W原子比例下,1.23 V_(RHE)偏压时的光电流从0.07 m A cm^(-2)显著地增加到0.46 m A cm^(-2).与对应的颗粒组装薄膜光阳极(通过固相反应结合涂覆-粘结后处理得以制备)相比较,喷雾热裂解法所制备的光阳极有利于降低电阻和促进电荷传输.
基金This work is supported by the National Key Research and Development Program of China(No.2018YFA0209303)the National Natural Science Foundation of China(Nos.U1663228 and 21473090)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.Z.L.thanks Prof.Xizhang Wang(School of Chemistry and Chemical Engineering,Nanjing University)for the nice discussion.
文摘The synthesis of perovskite oxynitrides,which are promising photoanode candidates for solar energy conversion,is normally accomplished by high-temperature ammonolysis of oxides and carbonate precursors,thus making the deposition of their planar films onto conductive substrates challenging.Here,we proposed a facile strategy to prepare a series of perovskite oxynitride films.Taking SrTaO_(2)N as a prototype,we prepared SrTaO_(2)N films on Ta foils under NH_(3) flow by utilizing the vaporized SrCl_(2)/SrCO_(3) eutectic salt.The SrTaO_(2)N films exhibit solar water-splitting photocurrents of 3.0 mA cm^(-2) at 1.23 V vs.RHE(reversible hydrogen electrode),which increases by 270%compared to the highest photocurrent(1.1 mA cm^(-2) at 1.23 V vs.RHE)of SrTaO_(2)N reported in the literature.This strategy may also be applied to directly prepare a series of perovskite oxynitride films on conductive substrates such as ATaO_(2)N(A=Ca,Ba)and ANbO_(2)N(A=Sr,Ba).
