JP4417657B2 - Method for improving fluorescence intensity of inorganic fluorescent particles - Google Patents

Description

【００１２】
上記蛍光物質として用いることのできる無機化合物としては、３〜１６族の金属元素からなる蛍光物質であれば特に限定されず、例えば、ユウロピウム、テルビニウム、サマリウム、ジスプロシウム等の希土類化合物や、カドミウム、亜鉛等のカルコゲン化合物等からなる無機蛍光粒子、３〜１６族の金属元素の有機金属化合物が挙げられる。
上記有機金属化合物としては、例えば、ビス（８−ヒドロキシキノリン）亜鉛、トリス（ジベンゾイルメタン）−モノ（フェナンチロリン）ユウロピウム（ＩＩＩ）、トリス（２−フェニルピリジン）イリジウム、トリス（８−ヒドロキシキノリン）アルミニウム（ＩＩＩ）、トリス（８−ヒドロキシキノリン）ガリウム（ＩＩＩ）等が挙げられる。
上記無機蛍光粒子としては、例えば、ＢａＭｇＡｌ_１０Ｏ_１７Ｅｕ、Ｙ_２Ｏ_３Ｅｕ、（Ｙ，Ｇｄ）ＢＯ_３Ｅｕ、ＣｄＳ、ＣｄＳｅ等が挙げられる。
更に、これらの複合材料としては、例えば、ＣｄＳをコア−ＣｄＳｅをシェル、ＣｄＳｅをコア−ＣｄＳをシェル、ＣｄＳをコア−ＺｎＳをシェル、ＣｄＳｅをコア−ＺｎＳをシェル、ＣｄＳｅのナノ結晶をコア−ＺｎＳをシェル、ＣｄＳｅのナノ結晶をコア−ＺｎＳｅをシェルとするコア−シェル構造を有するもの等が挙げられる。
なかでも、上記蛍光物質としては、上記無機蛍光粒子が好ましい。
これらの蛍光物質は単独で用いてもよく、２種以上を併用してもよい。
【００１３】
また、上記無機蛍光粒子の表面は、化学的又は物理的に修飾されていてもよく、界面活性剤、分散安定剤又は酸化防止剤等の添加剤が加えられたものであってもよい。このような界面活性剤及び／又は表面修飾剤を加えることにより、上記無機蛍光粒子を媒体に分散するときの分散性を向上させることができる。
【００１４】
上記無機蛍光粒子の粒子径としては特に限定されないが、通常、好ましい下限は０．５ｎｍ、好ましい上限は１００ｎｍである。この範囲内であると、比較的高い蛍光強度や媒体に分散させたときの分散安定性を得ることができる。より好ましい下限は１ｎｍ、より好ましい上限は５０ｎｍ、更に好ましい上限は１０ｎｍである。
【００１５】
上記蛍光物質は、上記無機蛍光粒子が無極性官能基及び／又は極性官能基を有する有機化合物で表面修飾されているものであってもよい。上記蛍光物質がこのような構造をとることにより、水又は有機溶媒への分散性、分散安定性が向上する。また、上記官能基同士の電荷の反発により蛍光物質が凝集することを抑制できる。
上記無極性及び／又は極性官能基を有する有機化合物としては、例えば、オクタンチオール、トリオクチルホスフィン、トリオクチルホスフィンオキサイド、メルカプトフェノール、メルカプトプロピオン酸、メルカプトウンデカン酸、アミノプロパンチオール等が挙げられる。
【００１６】
上記蛍光物質は、正又は負の電荷を有していることが好ましい。正又は負の電荷を有することにより、例えば、静電引力によって後述する支持体や分子認識物質等と容易に接合することができる。また、蛍光物質同士は静電反発することから、支持体や分子認識物質に、蛍光物質同士が重なって結合することを防止することができる。
【００１７】
上記蛍光物質に正又は負の電荷を帯電させる方法としては、例えば、上記蛍光物質に正又は負の電荷を有する材質を用いる方法や正又は負の電荷を有する表面修飾剤を用いる方法等が挙げられる。また、上記蛍光物質が無機蛍光粒子と極性官能基を有する有機化合物とからなる場合には、正又は負の電荷を有する有機化合物を用いることで容易に上記蛍光物質に正又は負の電荷を帯電させることができる。具体的には、例えば、負の電荷を帯電させる場合にはメルカプトプロピオン酸、メルカプトウンデカン酸等を用い、正の電荷を帯電させる場合にはアミノプロパンチオール等を用いる。
【００１８】
上記蛍光物質は、支持体と接合して用いてもよい。
上記支持体としては、上記蛍光物質を接合させることができ、かつ、上記蛍光物質の蛍光発光を阻害しないものであれば特に限定されず、例えば、ガラス、シリカ等の無機化合物、樹脂等の有機化合物、有機・無機複合材料等が挙げられる。また、上記支持体の形状としては特に限定されないが、微粒子、基板、薄膜、繊維、中空糸からなる群より選択される少なくとも１つの形状を有することが好ましく、その目的に応じて適切なものを選択することができる。なかでも、微粒子であることが好ましい。
【００１９】
上記蛍光物質と支持体との接合の態様としては特に限定されず、例えば、蛍光物質を支持体上に焼成させてもよいし、疎水性相互作用、親水性相互作用、静電引力、化学結合等により接合してもよい。
【００２０】
また、上記蛍光物質を分子認識蛍光体のマーカー物質として用いる場合には、分子認識物質を蛍光物質又は蛍光物質に接合した上記支持体に接合して用いてもよい。
上記分子認識物質としては、標的物質に特異的に反応するものであれば特に限定されないが、抗原、抗体等のタンパク質、ＤＮＡ、ＲＮＡ等の核酸、シクロデキストリン、クラウンエーテル等の環状化合物等が挙げられる。
【００２１】
上記分子認識蛍光体と上記蛍光物質又は支持体との接合の態様としては特に限定されず、例えば、疎水性相互作用、親水性相互作用、静電引力、化学結合等により接合する態様が挙げられる。
【００２２】
上記蛍光物質をアジ化ナトリウム及び／又は電子供与体と併用することにより蛍光物質の蛍光強度を飛躍的に向上させることができる。即ち、アジ化ナトリウムと電子供与体は、蛍光強度向上剤としての機能を有する。本発明の方法により蛍光強度が向上した蛍光物質は、プラズマディスプレイパネルに用いた場合には輝度の高い画像が得られ、マーカー物質に用いた場合には高い感度が得られる。
また、上記蛍光物質をアジ化ナトリウム及び／又は電子供与体と併用することにより、量子ドットのブリンキングを制御して、ブリンキングの発生を抑制することができ、本発明の方法により蛍光強度が向上した蛍光物質をプラズマディスプレイパネルに用いた場合に画像がちらついたりするのを防ぐことができ、マーカー物質に用いた場合に感度がばらついたりするのを防ぐことができる。なお、ここでブリンキングとは蛍光強度が変動して大きくなったり、小さくなったりすることを意味する。
【００２３】
上記電子供与体としては特に限定されないが、親水性化合物が好ましく、なかでも、ピロール（Ｃ_４Ｈ_５Ｎ）、アスコルビン酸及びホウ素化テトラメチルアンモニウムからなる群より選択される少なくとも１種が好適である。
アジ化ナトリウムと電子供与体とは、単独で用いてもよいし、併用してもよい。
【００２４】
上記蛍光物質とアジ化ナトリウム及び／又は電子供与体との併用の態様としては特に限定されないが、例えば、上記蛍光物質と、アジ化ナトリウム及び／又は電子供与体とを直接的又は間接的に接合する方法；上記蛍光物質を、アジ化ナトリウム及び／又は電子供与体を含有する溶液中に懸濁する方法等が好適である。
【００２５】
上記蛍光物質と、アジ化ナトリウム及び／又は電子供与体とを直接的又は間接的に接合する方法を採る場合には、アジ化ナトリウム及び／又は電子供与体は上記蛍光物質に直接接合してもよいし、上記蛍光物質に上記支持体や分子認識物質が接合している場合には、支持体又は分子認識物質を介して間接的に接合してもよい。
なお、ここで接合には、物理的又は化学的な方法により上記蛍光物質等の表面にアジ化ナトリウム及び／又は電子供与体を結合させることの他、上記蛍光物質等内にアジ化ナトリウム及び／又は電子供与体を含有させることをも含む。
【００２６】
上記蛍光物質等と、アジ化ナトリウム及び／又は電子供与体とを接合する方法としては、例えば、上記蛍光物質等の表面にアジ化ナトリウム及び／又は電子供与体を吸着させる方法が好適である。
【００２７】
上記蛍光物質を、アジ化ナトリウム及び／又は電子供与体を含有する溶液中に懸濁する方法を採る場合には、上記蛍光物質、又は、上記蛍光物質に支持体や分子認識物質が接合している場合にはこれらの接合体を、アジ化ナトリウム及び／又は電子供与体を含有する溶液を用いて懸濁させる。
【００２８】
上記アジ化ナトリウム及び／又は電子供与体を含有する溶液の溶媒としては、これらを溶解することができ、かつ、上記蛍光物質の蛍光強度を抑制しないものであれば特に限定されないが、生体物質の分子認識蛍光体として用いる場合には精製水、生理食塩水等が好適である。
上記溶液中における、アジ化ナトリウム及び／又は電子供与体の濃度の好ましい下限は０．００１重量％、好ましい上限は３０重量％である。０．００１重量％未満であると、充分な蛍光強度向上効果が得られないことがあり、３０重量％を超えると、蛍光物質や支持体が凝集してかえって蛍光強度が低下することがある。
【００２９】
本発明の蛍光物質の蛍光強度を向上させる方法では、蛍光物質をアジ化ナトリウム及び／又は電子供与体と併用するだけで、極めて容易に蛍光物質の蛍光強度を向上させることができる。また、併用の態様も種々選択できることから、極めて汎用性が高い方法である。
本発明の方法を用いることにより、プラズマディスプレイパネル（ＰＤＰ）の輝度を飛躍的に向上させたり、また、生体関連物質の検出感度を飛躍的に向上させたりすることができ、蛍光物質の応用範囲を拡大することができる。
【００３０】
【実施例】
以下に実施例を掲げて本発明を更に詳しく説明するが、本発明はこれら実施例のみに限定されるものではない。
【００３１】
（実施例１）
蛍光物質として、３６５ｎｍの励起光を照射することで５６０ｎｍの蛍光を発する、表面をメルカプトウンデカン酸で親水処理したコアシェル型ＣｄＳｅ／ＺｎＳ粒子を選択した。この蛍光物質は、平均粒子径が約４．２ｎｍ、ゼータ電位が−４５ｍＶであった。
この蛍光物質を固形分濃度０．１重量％となるように精製水に分散し、得られた分散液にアジ化ナトリウムを１重量％となるように添加して、蛍光物質のアジ化ナトリウム水溶液分散液を得た。
【００３２】
（実施例２）
蛍光物質として、３６５ｎｍの励起光を照射することで５６０ｎｍの蛍光を発する、表面をメルカプトウンデカン酸で親水処理したコアシェル型ＣｄＳｅ／ＺｎＳ粒子を選択した。この蛍光物質は、平均粒子径が約４．２ｎｍ、ゼータ電位が−４５ｍＶであった。
この蛍光物質を固形分濃度０．１重量％となるように精製水に分散し、得られた分散液にピロールを１重量％となるように添加して、蛍光物質のピロール水溶液分散液を得た。
【００３３】
（比較例１）
蛍光物質として、３６５ｎｍの励起光を照射することで５６０ｎｍの蛍光を発する、表面をメルカプトウンデカン酸で親水処理したコアシェル型ＣｄＳｅ／ＺｎＳ粒子を選択した。この蛍光物質は、平均粒子径が約４．２ｎｍ、ゼータ電位が−４５ｍＶであった。
この蛍光物質を固形分濃度０．１重量％となるように精製水に分散し、蛍光物質の水分散液を得た。
【００３４】
（実施例３）
メタクリル酸グリシジル２４ｇ、ジメタクリル酸エチレングリコール０．９３ｇ、メタクリル酸エチレントリメチルアンモニウム塩酸塩０．４９ｇからなるモノマー混合物を水５００ｇに窒素バブリングしながら回転速度２５０ｒｐｍで分散させた。窒素フロー下でアゾ系開始剤としてアゾビスアミジノプロパン２塩酸塩０．６５ｇを加え、７０℃で２４時間反応させ、有機化合物からなる支持体を作製した。得られた支持体の平均粒子径は４９３ｎｍ、粒度分布（ＣＶ）は１５％、ゼータ電位は＋３９ｍＶであった。
得られた支持体を固形分濃度０．１重量％となるように精製水に懸濁させて支持体分散液を調製した。
【００３５】
一方、蛍光物質として、３６５ｎｍの励起光を照射することで５６０ｎｍの蛍光を発する、表面をメルカプトウンデカン酸で親水処理したコアシェル型ＣｄＳｅ／ＺｎＳ粒子を選択した。この蛍光物質は、平均粒子径が約４．２ｎｍ、ゼータ電位が−４５ｍＶであった。
この蛍光物質を固形分濃度０．１重量％となるように精製水に分散して蛍光物質分散液を調製した。
【００３６】
調製した支持体の分散液２００μＬに蛍光物質の分散液２０μＬをホモジナイザーで撹拌しながら添加し、支持体と蛍光物質とを接合した。遠心分離（６５００ｒｐｍ、６０ｍｉｎ）により接合体を沈殿し、上澄み液を採取した後、沈殿に１％アジ化ナトリウム水溶液６００μＬを加え再分散した。このようにして支持体に蛍光物質が接合した発光性素子のアジ化ナトリウム水溶液分散液を得た。
【００３７】
（実施例４）
実施例３で調製した支持体の分散液２００μＬに蛍光物質の分散液２０μＬをホモジナイザーで撹拌しながら添加し、支持体と蛍光物質とを接合した。遠心分離（６５００ｒｐｍ、６０ｍｉｎ）により接合体を沈殿し、上澄み液を採取した後、沈殿に０．１％ピロール水溶液６００μＬを加え再分散した。このようにして支持体に蛍光物質が接合した発光性素子のピロール水溶液分散液を得た。
【００３８】
（比較例２）
実施例３で調製した支持体の分散液２００μＬに蛍光物質の分散液２０μＬをホモジナイザーで撹拌しながら添加し、支持体と蛍光物質とを接合した。遠心分離（６５００ｒｐｍ、６０ｍｉｎ）により接合体を沈殿し、上澄み液を採取した後、沈殿に精製水６００μＬを加え再分散した。このようにして支持体に蛍光物質が接合した発光性素子の水分散液を得た。
【００３９】
実施例１〜４及び比較例１、２で得られた発光性素子の分散液とその作製の際に採取した上澄み液の蛍光波長及び蛍光強度を日本分光社製ＦＰ−６５００を用いて測定した。即ち、上澄み液に精製水４００μＬを加えたものを対照として、発光性素子の分散液について３６５ｎｍの励起光を３万秒間照射した後の４００〜７００ｎｍの蛍光を測定し、４１０ｎｍに観察される水のピークを基準とし、５６０ｎｍに観察される蛍光の相対強度Ａを下記式に従い算出した。
相対強度Ａ＝５６０ｎｍの強度／４１０ｎｍの強度×１００
結果を表１に示した。
【００４０】
表１より、アジ化ナトリウム又はピロールを併用した場合には、著しく蛍光強度が向上することがわかった。
【００４１】
【表１】

【００４２】
【発明の効果】
本発明によれば、容易かつ高い汎用性で蛍光物質の蛍光強度を向上させる方法及び蛍光強度向上剤を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for improving the fluorescence intensity emitted by a fluorescent substance with ease and high versatility, and a fluorescence intensity improver.
[0002]
[Prior art]
Fluorescent substances are used in various applications such as display devices, fluorescent lamps, marker substances for detecting biological substances.
For example, in a plasma display panel (PDP), a display cell having a function of emitting light when excited by ultraviolet light is used, and a fluorescent material is applied inside the display cell. A rare gas such as He—Xe or Ar is sealed inside the cell. When a voltage is applied to the discharge electrode, discharge occurs in the rare gas, and vacuum ultraviolet rays are emitted. The phosphor is excited by the vacuum ultraviolet rays and emits visible light. An image is displayed by designating the position of the display cell that emits light, and a full color display can be performed by using phosphors of blue, green, and red whose emission colors are the three primary colors of light.
In addition, as a method for measuring biologically related substances such as antigens, antibodies, and DNA, and environment-related substances such as dioxin with high sensitivity, molecular recognition phosphors that bind to molecular recognition substances using fluorescent substances as marker substances are used. .
[0003]
As such fluorescent substances, for example, rare earth oxides such as BaMgAl ₁₀ O ₁₇ : Eu and Y ₂ O ₃ : Eu; metal chalcogenides such as CdS and CdSe are known.
In recent years, inorganic ultrafine particles (hereinafter also referred to as inorganic nanoparticles) have attracted attention as fluorescent substances that can be used for highly sensitive marker substances. Inorganic nanoparticles are characterized by high fluorescence intensity and a narrow half-width of the fluorescence spectrum, that is, sharp fluorescence. Inorganic nanoparticles are semiconductor ultrafine particles (ultrafine crystals) having a particle diameter equivalent to the excited particle Bohr radius in the bulk crystal, and the optical spectrum, that is, the absorption spectrum and the fluorescence spectrum are changed depending on the particle diameter by the manifestation of the quantum confinement effect. It is possible to adjust. That is, light having different wavelengths can be emitted depending on the particle diameter.
[0004]
However, the fluorescence intensity of these fluorescent materials is not always sufficient. If the fluorescence intensity of the fluorescent substance can be improved, for example, the brightness of the plasma display panel (PDP) can be dramatically improved, and the detection sensitivity of the biological substance can be dramatically improved. The application range of fluorescent materials can be further expanded.
[0005]
As a method for improving the fluorescence intensity of a fluorescent substance, for example, Patent Document 1 discloses a fluorescence intensity enhancement chip using silicon dioxide as a dielectric. However, this method has a problem that the manufacture of the chip is complicated and expensive, and it can be used only in a chip shape and lacks versatility.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-340802
[Problems to be solved by the invention]
The present invention has been made in view of the above situation, and an object of the present invention is to provide a method and a fluorescent intensity improver for improving the fluorescence intensity of a fluorescent substance with high versatility easily.
[0008]
[Means for Solving the Problems]
The present invention relates to inorganic fluorescent particles obtained by subjecting the surface of particles having a particle diameter of 0.5 to 100 nm that emits fluorescence when irradiated with excitation light to hydrophilic treatment with mercaptoundecanoic acid, and inorganic fluorescent particles using sodium azide or pyrrole in combination. This is a method for improving the fluorescence intensity.
The present invention is described in detail below.
[0009]
As a result of intensive studies, the present inventors have surprisingly found that the fluorescence intensity of the fluorescent substance can be remarkably improved only by using the fluorescent substance in combination with sodium azide and / or an electron donor. The invention has been completed.
The fluorescent substance is not particularly limited as long as it emits fluorescence when irradiated with excitation light, and any organic compound or inorganic compound can be used. Among them, a fluorescent substance made of an inorganic compound can be suitably used because it has sharp fluorescence and high stability.
[0010]
Examples of the organic compound that can be used as the fluorescent substance include proteins such as luciferase, fluorescein isothiocyanate (FITC) represented by the following formula (1), rhodamine, and the like.
[0011]
[Chemical 1]

[0012]
The inorganic compound that can be used as the fluorescent material is not particularly limited as long as it is a fluorescent material composed of a metal element of Group 3 to 16. For example, rare earth compounds such as europium, terbium, samarium, dysprosium, cadmium, and zinc Inorganic fluorescent particles composed of a chalcogen compound such as, and organometallic compounds of group 3-16 metal elements.
Examples of the organometallic compound include bis (8-hydroxyquinoline) zinc, tris (dibenzoylmethane) -mono (phenanthyroline) europium (III), tris (2-phenylpyridine) iridium, and tris (8-hydroxy). Quinoline) aluminum (III), tris (8-hydroxyquinoline) gallium (III) and the like.
Examples of the inorganic fluorescent particles include BaMgAl ₁₀ O ₁₇ Eu, Y ₂ O ₃ Eu, (Y, Gd) BO ₃ Eu, CdS, CdSe, and the like.
Further, as these composite materials, for example, CdS is core-CdSe shell, CdSe is core-CdS shell, CdS is core-ZnS shell, CdSe is core-ZnS shell, CdSe nanocrystal is core- Examples include those having a core-shell structure in which ZnS is a shell and CdSe nanocrystals are core-ZnSe as a shell.
Among these, as the fluorescent material, the inorganic fluorescent particles are preferable.
These fluorescent materials may be used alone or in combination of two or more.
[0013]
The surface of the inorganic fluorescent particles may be chemically or physically modified, and may be added with additives such as a surfactant, a dispersion stabilizer or an antioxidant. By adding such a surfactant and / or a surface modifier, the dispersibility when the inorganic fluorescent particles are dispersed in a medium can be improved.
[0014]
Although it does not specifically limit as a particle diameter of the said inorganic fluorescent particle, Usually, a preferable minimum is 0.5 nm and a preferable upper limit is 100 nm. Within this range, relatively high fluorescence intensity and dispersion stability when dispersed in a medium can be obtained. A more preferred lower limit is 1 nm, a more preferred upper limit is 50 nm, and a still more preferred upper limit is 10 nm.
[0015]
The fluorescent substance may be one in which the inorganic fluorescent particles are surface-modified with an organic compound having a nonpolar functional group and / or a polar functional group. When the fluorescent substance has such a structure, dispersibility and dispersion stability in water or an organic solvent are improved. Moreover, it can suppress that a fluorescent material aggregates by the repulsion of the charge of the said functional groups.
Examples of the organic compounds having nonpolar and / or polar functional groups include octanethiol, trioctylphosphine, trioctylphosphine oxide, mercaptophenol, mercaptopropionic acid, mercaptoundecanoic acid, aminopropanethiol, and the like.
[0016]
The fluorescent material preferably has a positive or negative charge. By having a positive or negative charge, for example, it can be easily bonded to a support or a molecular recognition substance described later by electrostatic attraction. Further, since the fluorescent materials repel each other, it is possible to prevent the fluorescent materials from overlapping and binding to the support or the molecular recognition material.
[0017]
Examples of a method for charging the fluorescent substance with a positive or negative charge include a method using a material having a positive or negative charge for the fluorescent substance and a method using a surface modifier having a positive or negative charge. It is done. Further, when the fluorescent substance is composed of inorganic fluorescent particles and an organic compound having a polar functional group, the fluorescent substance can be easily charged with a positive or negative charge by using an organic compound having a positive or negative charge. Can be made. Specifically, for example, mercaptopropionic acid, mercaptoundecanoic acid or the like is used when charging a negative charge, and aminopropanethiol or the like is used when charging a positive charge.
[0018]
You may use the said fluorescent substance joined to a support body.
The support is not particularly limited as long as it can join the fluorescent material and does not inhibit the fluorescence emission of the fluorescent material. For example, the support is an inorganic compound such as glass or silica, or an organic material such as a resin. Examples thereof include compounds and organic / inorganic composite materials. The shape of the support is not particularly limited, but preferably has at least one shape selected from the group consisting of fine particles, substrates, thin films, fibers, and hollow fibers, and has an appropriate shape depending on the purpose. You can choose. Of these, fine particles are preferable.
[0019]
The mode of bonding between the fluorescent material and the support is not particularly limited. For example, the fluorescent material may be baked on the support, or a hydrophobic interaction, a hydrophilic interaction, an electrostatic attraction, or a chemical bond. You may join by etc.
[0020]
Moreover, when using the said fluorescent substance as a marker substance of a molecule | numerator recognition fluorescent substance, you may join and use the molecular recognition substance on the said support body joined to the fluorescent substance or the fluorescent substance.
The molecular recognition substance is not particularly limited as long as it specifically reacts with the target substance, and examples thereof include proteins such as antigens and antibodies, nucleic acids such as DNA and RNA, and cyclic compounds such as cyclodextrin and crown ether. It is done.
[0021]
The mode of joining the molecular recognition phosphor and the fluorescent material or the support is not particularly limited, and examples thereof include a mode of joining by hydrophobic interaction, hydrophilic interaction, electrostatic attraction, chemical bond, and the like. .
[0022]
By using the fluorescent substance in combination with sodium azide and / or an electron donor, the fluorescence intensity of the fluorescent substance can be dramatically improved. That is, sodium azide and an electron donor have a function as a fluorescent intensity improver. When the fluorescent substance whose fluorescence intensity is improved by the method of the present invention is used for a plasma display panel, an image with high luminance is obtained, and when it is used for a marker substance, high sensitivity is obtained.
Further, by using the fluorescent substance in combination with sodium azide and / or an electron donor, it is possible to control the blinking of the quantum dots and suppress the occurrence of blinking, and the fluorescence intensity is increased by the method of the present invention. When the improved fluorescent material is used for the plasma display panel, it is possible to prevent the image from flickering, and when used for the marker material, the sensitivity can be prevented from varying. Here, blinking means that the fluorescence intensity fluctuates to increase or decrease.
[0023]
Is not particularly restricted but the electron donor is preferably a hydrophilic compound, among others, pyrrole (C 4 _{H 5 N),} at least one is preferably selected from the group consisting of ascorbic acid and borated tetramethylammonium is there.
Sodium azide and an electron donor may be used alone or in combination.
[0024]
The embodiment of the combined use of the fluorescent material and sodium azide and / or electron donor is not particularly limited. For example, the fluorescent material and sodium azide and / or electron donor are joined directly or indirectly. A method of suspending the fluorescent substance in a solution containing sodium azide and / or an electron donor is preferable.
[0025]
When the method of directly or indirectly joining the fluorescent substance and sodium azide and / or electron donor is employed, the sodium azide and / or electron donor may be directly joined to the fluorescent substance. Alternatively, when the support or the molecular recognition substance is bonded to the fluorescent substance, the fluorescent substance may be indirectly bonded via the support or the molecular recognition substance.
Here, for bonding, in addition to binding sodium azide and / or an electron donor to the surface of the fluorescent substance or the like by a physical or chemical method, sodium azide and / or Or including an electron donor is also included.
[0026]
As a method for joining the fluorescent substance or the like with sodium azide and / or an electron donor, for example, a method of adsorbing sodium azide and / or an electron donor on the surface of the fluorescent substance or the like is suitable.
[0027]
When the method of suspending the fluorescent substance in a solution containing sodium azide and / or an electron donor is employed, a support or a molecular recognition substance is bonded to the fluorescent substance or the fluorescent substance. If so, these conjugates are suspended using a solution containing sodium azide and / or an electron donor.
[0028]
The solvent of the solution containing sodium azide and / or electron donor is not particularly limited as long as it can dissolve these and does not suppress the fluorescence intensity of the fluorescent substance. When used as a molecular recognition phosphor, purified water, physiological saline and the like are suitable.
The preferable lower limit of the concentration of sodium azide and / or electron donor in the solution is 0.001% by weight, and the preferable upper limit is 30% by weight. If the amount is less than 0.001% by weight, a sufficient effect of improving the fluorescence intensity may not be obtained. If the amount exceeds 30% by weight, the fluorescent substance or the support may aggregate to reduce the fluorescence intensity.
[0029]
In the method for improving the fluorescence intensity of the fluorescent substance of the present invention, the fluorescence intensity of the fluorescent substance can be improved very easily only by using the fluorescent substance in combination with sodium azide and / or an electron donor. Moreover, since various modes of combination can be selected, the method is extremely versatile.
By using the method of the present invention, the brightness of a plasma display panel (PDP) can be dramatically improved, and the detection sensitivity of biological materials can be dramatically improved. Can be enlarged.
[0030]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0031]
Example 1
As the fluorescent material, core-shell type CdSe / ZnS particles that emit fluorescence at 560 nm by irradiation with excitation light at 365 nm and whose surface was hydrophilized with mercaptoundecanoic acid were selected. This fluorescent material had an average particle size of about 4.2 nm and a zeta potential of −45 mV.
This fluorescent substance is dispersed in purified water so as to have a solid content concentration of 0.1% by weight, and sodium azide is added to the obtained dispersion so as to be 1% by weight. A dispersion was obtained.
[0032]
(Example 2)
As the fluorescent material, core-shell type CdSe / ZnS particles that emit fluorescence at 560 nm by irradiation with excitation light at 365 nm and whose surface was hydrophilized with mercaptoundecanoic acid were selected. This fluorescent material had an average particle size of about 4.2 nm and a zeta potential of −45 mV.
This fluorescent substance is dispersed in purified water so as to have a solid concentration of 0.1% by weight, and pyrrole is added to the obtained dispersion so as to be 1% by weight to obtain a pyrrole aqueous solution dispersion of the fluorescent substance. It was.
[0033]
(Comparative Example 1)
As the fluorescent material, core-shell type CdSe / ZnS particles that emit fluorescence at 560 nm by irradiation with excitation light at 365 nm and whose surface was hydrophilized with mercaptoundecanoic acid were selected. This fluorescent material had an average particle size of about 4.2 nm and a zeta potential of −45 mV.
This fluorescent material was dispersed in purified water so as to have a solid content concentration of 0.1% by weight to obtain an aqueous dispersion of the fluorescent material.
[0034]
(Example 3)
A monomer mixture consisting of 24 g of glycidyl methacrylate, 0.93 g of ethylene glycol dimethacrylate, and 0.49 g of ethylene trimethylammonium methacrylate was dispersed in 500 g of water at a rotational speed of 250 rpm while bubbling nitrogen. Under a nitrogen flow, 0.65 g of azobisamidinopropane dihydrochloride as an azo initiator was added and reacted at 70 ° C. for 24 hours to prepare a support made of an organic compound. The average particle diameter of the obtained support was 493 nm, the particle size distribution (CV) was 15%, and the zeta potential was +39 mV.
The obtained support was suspended in purified water to a solid content concentration of 0.1% by weight to prepare a support dispersion.
[0035]
On the other hand, as the fluorescent material, core-shell CdSe / ZnS particles that emit fluorescence at 560 nm when irradiated with excitation light at 365 nm and whose surface was hydrophilized with mercaptoundecanoic acid were selected. This fluorescent material had an average particle size of about 4.2 nm and a zeta potential of −45 mV.
This fluorescent substance was dispersed in purified water so as to have a solid content concentration of 0.1% by weight to prepare a fluorescent substance dispersion.
[0036]
To 200 μL of the prepared support dispersion, 20 μL of the fluorescent substance dispersion was added with stirring by a homogenizer, and the support and the fluorescent substance were joined. The conjugate was precipitated by centrifugation (6500 rpm, 60 min), and the supernatant was collected, and then 600 μL of 1% aqueous sodium azide solution was added to the precipitate for redispersion. In this way, a sodium azide aqueous solution dispersion of the light emitting device in which the fluorescent material was bonded to the support was obtained.
[0037]
Example 4
To 200 μL of the support dispersion prepared in Example 3, 20 μL of the fluorescent substance dispersion was added with stirring by a homogenizer, and the support and the fluorescent substance were joined. The conjugate was precipitated by centrifugation (6500 rpm, 60 min), and the supernatant was collected. Then, 600 μL of 0.1% pyrrole aqueous solution was added to the precipitate and redispersed. In this manner, a pyrrole aqueous solution dispersion of a light emitting device in which a fluorescent material was bonded to a support was obtained.
[0038]
(Comparative Example 2)
To 200 μL of the support dispersion prepared in Example 3, 20 μL of the fluorescent substance dispersion was added with stirring by a homogenizer, and the support and the fluorescent substance were joined. The conjugate was precipitated by centrifugation (6500 rpm, 60 min), and the supernatant was collected, and then 600 μL of purified water was added to the precipitate for redispersion. In this way, an aqueous dispersion of the light emitting device in which the fluorescent material was bonded to the support was obtained.
[0039]
The fluorescence wavelengths and the fluorescence intensities of the dispersions of the luminescent elements obtained in Examples 1 to 4 and Comparative Examples 1 and 2 and the supernatants collected during the production were measured using FP-6500 manufactured by JASCO Corporation. . That is, using a supernatant obtained by adding 400 μL of purified water as a control, the fluorescence of 400 to 700 nm after irradiation of 365 nm excitation light for 30,000 seconds was measured for the dispersion of the luminescent element, and the water observed at 410 nm was measured. The relative intensity A of fluorescence observed at 560 nm was calculated according to the following formula.
Relative intensity A = 560 nm intensity / 410 nm intensity × 100
The results are shown in Table 1.
[0040]
From Table 1, it was found that when sodium azide or pyrrole was used in combination, the fluorescence intensity was significantly improved.
[0041]
[Table 1]

[0042]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the method and fluorescence intensity improving agent which improve the fluorescence intensity of a fluorescent substance easily and with high versatility can be provided.

Claims (3)

An inorganic fluorescent particle comprising a combination of inorganic fluorescent particles having a surface diameter of 0.5 to 100 nm that emits fluorescence when irradiated with excitation light and hydrophilized with mercaptoundecanoic acid, and sodium azide or pyrrole. A method for improving fluorescence intensity. It is characterized by directly or indirectly joining inorganic fluorescent particles obtained by hydrophilic treatment with mercaptoundecanoic acid on a surface having a particle diameter of 0.5 to 100 nm that emits fluorescence when irradiated with excitation light, and sodium azide or pyrrole. A method for improving the fluorescence intensity of the inorganic fluorescent particles. It is characterized in that inorganic fluorescent particles obtained by hydrotreating the surface of a particle diameter of 0.5 to 100 nm that emits fluorescence when irradiated with excitation light with mercaptoundecanoic acid are suspended in a solution containing sodium azide or pyrrole. To improve the fluorescence intensity of the inorganic fluorescent particles.