Fuji

TECHNICAL INFORMATION

Quantum Dot
Quantum Dot is the nano meter sized semiconductor crystal with specific opticalproperties originates from the phenomenon which can be explained by the quantum
chemistry and quantum mechanics . They have generally size range of 2-10 nm andpossess 10-50 atoms in each particle. Band gap can be modified by controlling the size ofcolloidal nano crystal.

Therefore, they exhibit specific luminescence emission lightproperties depending on the particle size. Quantum dot exhibits not only luminescenceemission light wavelength modification and narrow spectral width but also have highquantum efficiency and absorb wide range of wavelength. The concept of energy level,band gap, conduction band, valence band can be applied to normal bulk sized
semiconductor except one clear difference.

In bulk status, the particle size ofsemiconductor is much larger than Exciton Bohr Radius and exciton can be reached tonature limit. On the other hand, when the particle size of semiconductor becomes closed
the size of Excition Bohr Radius, electron energy level losses its continuity and becomesseparate, namely small separation can be observed among energy level. This separated
energy status is called quantum confinement and semiconductor materials becomes nolonger bulk status but “quantum dot” status.

In this situation, absorbance and lightemission properties of semiconductor material is different. In quantum dot status, electron
moves between the edge of band gap just like in bulk semiconductor status.

In quantum

dot status, luminescence emission light wavelength can be easily precisely modified bychanging the particle size, by modifying the band gap size since emission light wavelength
depends on the band gap energy.
In our technology, basically, quantum dot can be dispersed in solution (water, various typeof organic solvent). Therefore, we can apply low cost printing and coating technology.
Quantum dot shows bright strong luminescence emission light. In addition, emission lightwith wide range of wavelength can be irradiated with high efficiency, long life time and highattenuation coefficient.
Therefore, quantum dot can be expected to be utilized for various type of applicationincluding medical experimental imaging, light source, display, solar cell, security tag,quantum dot laser, photonic material, transistor, thermoelectric material andquantum dot computer etc…

FUJI PIGMENT Co., Ltd.
2-23-2, Obana, Kawanishi, Hyogo 666-0015 JAPAN
Phone: 072- 759-8501 Facsimile: 072- 759-9008
Web : http://www.fuji-pigment.co.jp/

Fuji

TECHNICAL INFORMATION
Solar Cell

Solar cell with high efficiency can be prepared by low cost printing technology. Fluorescentdye which has been used already, have tendency to decompose as time elapse. On theother hand, quantum dot is the inorganic material and stable in this sense. Moreover,silicon based solar cell can only absorb visible light. In addition, organic dye is not applied
to utilizing infrared light region. In this regard, quantum dot can absorb infrared toultraviolet light just by modifying the particle size. Quantum dot exhibits high lightabsorbing efficiency even under weak light irradiation on such as cloudy days.

Bio Medical Imaging
Since quantum dot is extremely tiny particle, they can be delivered to anywhere in thebody. Therefore, they can be used for medical imaging and bio sensor.

Moreover, by

coating bio compatible polymer with quantum dot, they can be dispersed in blood vessels
too. In addition, by binding with specific substances such as antibody, they can be used
as target cell. At the moment, organic dye with wide spectra is used for fluorescent biosensor. However, fluorescent color choice is limited and fluorescent life time is short. In
contrast, quantum dot is able to emission light at all range of wavelength region. Also,
they exhibit high efficiency and long life time compared to existed organic dye.

Electronics, Photonics
Quantum dot is in zero dimension so that density of states is very distinctively clear andsharp compared to high dimension structure. Because quantum dot is extremely small insize, electrons do not necessary have to move long distance compared to large particle,
thus signal response becomes very quick in various type of electronic devices. Owing tothese electronic properties, quantum dot can be applied to transistor, solar cell, ultrafast
optical switching device, logical gate and quantum computer etc…in addition, high density
solid memory chips, LED, white solid light, back light, displays, photonics ink (security ink)
and light detector etc…can be created based on quantum dot technology.

FUJI PIGMENT Co., Ltd.
2-23-2, Obana, Kawanishi, Hyogo 666-0015 JAPAN
Phone: 072- 759-8501 Facsimile: 072- 759-9008
Web : http://www.fuji-pigment.co.jp/

Fuji

TECHNICAL INFORMATION

Generally, quantum dot is the semiconductor based on cadmium. However, these heavy
metals are prohibited to be used in many industry areas.

Therefore, demands are todevelop cadmium free quantum dot which exhibits high light emitting efficiency and stability
as good as cadmium based semiconductors. We are diligently researching and developing
cadmium contained quantum dot and also, cadmium free quantum dots and we will continue
to have more kinds of quantum dot products. In should be noted here that generally, tomanufacture quantum dots in large industrial level have difficulty due to cost issue.
Therefore, quantum dot is currently used for only in the field of bio medical imaging withsmall quantity business.

In this regard, we are chasing technology to manufacture

quantum dot in large industrial level in order to make quantum dot products with cheaper
price.
Solvent used is mainly water and various type of organic solvent. Please consult with usanytime if you have particular idea which solvent should be used. Also, if you need finerparticle size modification, please let us know. We are currently working on to develop otherquantum dots besides following products such as Ag based, Te based, Ni based, Mobased, silicon quantum dot, quantum rod etc… Below table presents the kind of quantum
dot we have at the moment. We are constantly improving quantum efficiency and also
developing other type of quantum dots as described above.
Please consult technical detail with us anytime.

Quantum Dot

Excitation
Wavelength（QY Max ）Emmision Peak
Wavelength（QY Max）

ZnS
CdSe
CdSe/ZnSInP/ZnS-Gr.
InP/ZnS-RedCuInS2/ZnS
CarbonGraphene

460
490
350
400
400
450
380
360

520
580
400
440
660
550
440
440

QY
Quantum
Efficiency
(%)
15 >
35 >
25 >
50 >
50 >
40 >
45 >
80 >

HalfWidth(nm)32  531 ± 554 ± 528 ± 535 ± 550 ± 525 ± 525 ± 5

FUJI PIGMENT Co., Ltd.
2-23-2, Obana, Kawanishi, Hyogo 666-0015 JAPAN
Phone: 072- 759-8501 Facsimile: 072- 759-9008
Web : http://www.fuji-pigment.co.jp/

Solvent

Octadecene
TolueneEthyle Glycol
Alcohol
Ketoneetc…

Water