FAQ's for Chemicals

What materials are used for Organic Photoconductors?

Organic Photoconducter Construction

Hole Transport Materials – Polyarylamine type structures with high charge mobility and excellent blending properties

Examples: ELC5022 (TPD), ELD7534 (alpha-NPD), ELB9241 (TTA)

Charge Generation Materials – High purity photoconductive pigments for a wide range of spectral responses and tunable sensitivity, supplied as dry powder or ready-to-use dispersion

Examples: ELA7051 (Y-TiOPc), ELA3847 (B-TiOPc)


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Why are photochromic colors darker on some days than others?

Photochromic colors are mostly affected by two factors:
  1.  The amount of activating UV present in the spectrum (the UVA spectrum changes from day to day).
  2.  Temperature (high temperature promotes transition from colored to colorless).

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Why is there a residual color when the photochromic transition should be clear?

There will be a slight residual color with photochromic transitions unless:
  1.  A reduction in  the photochromic loading is applied.
  2.  A reduction in  the processing temperature is applied.


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What should the photochromic be protected from?

The photochromic molecule needs to be protected from free radicals such as singlet oxygen, oxidizers such as peroxides, acids and high energy ultraviolet, UVB.  While it is robust in the closed or colorless form, it is most susceptible to attack in its open or colored state.


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What is absorptivity?

Absorptivity is a measure of the amount of light absorbed by a solution.  Usually defined by Beer’s Law, absorptivity is proportional to the concentration of the absorbing solute.

molar absorptivity is absorptivity defined in terms of concentrations expressed in moles per liter. Symbol e.

e=A/cl    c=M(moles/liter)

e has the units of L mol-1 cm-1

specific absorptivity is absorptivity defined in terms of concentrations expressed in grams per liter. Symbol a.

a =A/cl    c=grams/liter

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How long will photochromic features last?

Photochromics that form acidic compounds when exposed to sunlight will not last as long in certain materials.  In plastisol, the half life of these pigments have achieved greater than 40 hours in a QUV panel.  (The half life is the time it takes to reach one half the initial change in color intensity).   And with products in solvent cast urethane, they have shown a half life greater than 2,000 hours.


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Can you help me find a compound by its common name?

Yes, our staff has extensive knowledge of chemical structures, compounds, and nomenclatures. 

Name HWS#
CdPc ELA4057
FePc ELA1081
MgPc ELA8061
NPB (Alpha) ELD7534
NPB (Beta) ELB4821
P3HT OPA4732
PbPc MSA5301
SnOPc ELA2028
SnPc ELA1063
TiOPc (beta) ELA8052
TiOPc (gamma) ELA7051
TPD (mixture) ELA4021
VOPc ELA8070
ZnPc ELA5067

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What is the structure of a typical OLED?

OLED Construction

•    Mechanism of OLED Device
When power is supplied, electrons move and the current begins to flow: Electrons(-) from the Cathode move toward the Emitting Layer by the help of the Electron Transfer Layer, on the other hand, Holes(+: state of electrons released) from the Anode move toward the Emitting Layer by the help of the Hole Transfer Layer.

Electrons and Holes converged at the Emitting Layer of organic materials generate excitation with high level of energy when the excitation falls down to the lower energy state creating light.
The color of the light varies according to the organic materials forming the Emitting Layer, and Full color can be represented by each organic material emitting R,G,B colors. Contrary to LCD with the simple function of open/closing pixels, OLED utilizes self light-emitting organic materials.

•    Representative sample of OLED Materials
Hole Injection Material - OSA3847, OSD6815, OPB9241
Hole Transport Materials - OSC7534(NPB), OSA3939(MTDATA), OSA7140, OSA3251(DCBP)
Electron Transport / Hole Blocking Materials - OSA2480(TAZ), OPA1957, OPA1854
Host Materials - OSD4487(AlQ3)
Doped Host Materials - OSA9530(DPQA), OPA5719(DCM2), OPA1790, OSA1762
Polymeric & Small Molecule Light Emitting Materials - OHA9576(MEH-PPV), OSA7983 (DPVBi), OPA6495, OPA5632

All technical information we supply is based on our general experience and is given in good faith. It is always the user’s responsibility to evaluate the feasibility of using our products by carrying out trials under actual production conditions before proceeding with a commercial run.


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