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liloveyan银虫 (初入文坛)
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down-conversion in Er3+/Yb3+ co-doped YF3
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Abstract ：Er3+/Yb3+ co-doped YF3 powder is prepared by combining a nitrate decomposition method with a NH4HF2 fluorization process, from which efficient energy transfer induced down-conversion is achieved. An absorbed 365 nm near ultraviolet photon is split into two photons of 650 nm red and 1000 nm near infrared radiations, both falling in the responding region of Si-based solar cells. The quantum cutting mechanism has been proposed and discussed and the energy transfer efficiency for the quantum cutting is evaluated by developing an emission intensity ratio contrast method. The investigation might offer a new possible approach to achieve Si-based solar cells of high efficiency by down-converting the near ultraviolet part of the solar spectrum. Quantum cutting (QC) was firstly reported in Pr3+ doped YF3 and NaYF4 phosphors in the early 1970s [1, 2]. It could generate two low-energy photons from an absorbed incident high energy photon, by which the necessary redshift of the absorbed radiation is obtained without losing energy efficiency.This is considered as an exciting scenario toward the development of superior luminescent materials and devices After that, QC has also been witnessed in other materials doped with a single rare earth ion such as Pr3+, Tm3+and Gd3+。The QC down-conversion based on an ion-couple was firstly reported in LiGdF4 phosphor byWegh [5], of which a vacuum ultraviolet photon is absorbed by Gd3+ and two red photons are then emitted by Eu3+ ions. Thereafter, many people attached great importance to QC by the combination of two or even three ions such as Er3+ → Gd3+ [6], Gd3+→Tb3+ [7], Pr3+→Mn2+ [8], Pr3+→Cr3+ [9] and Er3+ → Gd3+ → Tb3+ [10]. In these cases, the absorbed energy of the donor ions is transferred stepwise to the acceptor ions, and two photons of low energy are obtained. These QC phosphors can enhance luminescence emission in the visible region and have important applications in more efficient plasma display panels and mercury-free fluorescent tubes. Recently, near infrared QC performed by cooperative energy transfers has been reported, which is also based on the combination of two ions [11–14]. In Tb3+ and Yb3+ codoped YPO4 [11], for instance, a cooperative energy transfer from Tb3+ to two Yb3+ ions leads to the photon doubling in the near infrared region. Similar phenomena have also been observed in several other rare earth coupled systems such as Pr3+ /Yb3+ [12], Tm3+ /Yb3+ [12, 13] and Ce3+ /Yb3+ [14] co-doped crystals or glasses. These phosphors can convert 484, 489, 475, and 330 nm photons into doubled 1000 nm photons, respectively. Since the energy of the converted photons is just above the band edge of crystalline Si, the energy losses by thermalization of electron hole pairs are minimized. Therefore, near infrared QC induced by cooperative energy transfer can enhance the energy efficiency of silicon-based solar cells in theory, which has attracted intense attention. |
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nyiwmy
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2楼2010-10-14 10:59:28
yanghongmei
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liloveyan(金币+5, 翻译EPI+1):辛苦你了，你是在线翻译的吧，呵呵，不过还是谢谢你 2010-10-18 14:03:21
| 摘要：掺Er3 + / Yb3 +共掺YF3粉末是通过将一个NH4HF2 fluorization过程中硝酸盐分解法，从有效的能量转移诱导下，转化率可达准备。紫外吸收的近365纳米的光子被分为两个光子波长为650纳米的红色和近红外辐射1000年，无论是在基础的太阳能电池下降的受访地区硅。切削机理的量子已经提出和讨论了量子降低能源转换效率通过制定排放强度比对比的方法进行评估。调查可能会提供一种新的可能的方法来实现下变频的太阳光谱的近紫外线部分的高效率硅太阳能电池。量子剪裁（QC）的首次报道了在镨+掺杂YF3，并在[1，2] 70年代初NaYF4荧光粉。它可以产生两个事件从一个高能量光子吸收低能量的光子，其中辐射的吸收红移是没有必要的损失是作为向上级发光材料和器件的发展令人激动的情景之后，认为获得的能量efficiency.This御用大律师也被目睹和Gd3 +其他材料掺杂+，铥与单一稀土离子如镨+。的质量控制下变频情侣基于一个离子被首次报道LiGdF4磷byWegh [5]，其中一真空紫外线光子吸收钆+和两个红色的光子，然后由Eu3 +离子发射。此后，许多人重视，甚至三离子重视两到质量控制的组合，如掺Er3 +→Gd3 +的[6]，钆+→Tb3 +的[7]，镨+→Mn2 +的[8]，镨+→三价铬+ [9]和Er3 +→钆铽+→+ [10]。在这种情况下，捐助离子吸收能量的逐步转移到受体离子和两个低能量光子得到。这些QC可以提高发光荧光粉在可见光区域发射显示器面板，并在重要的应用更有效的血浆和无汞荧光灯管。最近，近红外质量控制，以合作的能量转移进行了报道，这也是]基于11-14组合两个离子[。在铽+和Yb3 +共掺YPO4 [11]，例如，传输从铽能源+合作社+两个镱离子导致光子红外区域在不久的一倍。类似的现象也被观察到几个其他稀土镨耦合系统，如+ /镱+ [12]，铥/镱+ [12，13]和Ce3 + /镱+ [14]共掺晶体或眼镜。这些荧光粉可以转换484，489，475和330 nm的光子到1000 nm的光子一倍，分别为。由于光子的能量转换后的正上方，硅晶体的带边，电子空穴对的能量损失最小化的热化。因此，近红外质量控制转移引起的能量可以加强合作的强烈关注能量理论，吸引了效率，基于硅的太阳能电池研究。 |
3楼2010-10-18 13:01:08
liloveyan
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4楼2010-10-18 14:01:52
yanghongmei
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5楼2010-10-18 16:24:40
