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  1. #131
    Photo Engineer's Avatar
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    Like most books on emulsions, it speaks in generalities for the most part.

    PE

  2. #132
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    Just found this website. http://www.spectrum.kiev.ua/catalogue/?class=DY Spectrum Info - Fine Chemicals in Kiev, Ukraine.

    Spectrum Info Ltd. is a private company focused on laboratory scale synthesis of fine organic chemicals and combinatorial building blocks. We provide rare and commercially unavailable compounds for research chemists worldwide. Our office and laboratory facilities are located in the Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev.

    About 500 synthetic dyes of various classes covering the absorbance range 350-1100 nm are presented in the product list. Specialty dyes catalog includes laser dyes, fluorescent probes, dyes for WORM disks production and electrophotography, silver halide sensitizers for visible and near IR region, and indicators.


    Seems promising. I haven't identified any sensitizers yet, but searching "cyanine" brings up 26 hits.
    If you are the big tree, we are the small axe

  3. #133
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    Here's a good thread over at holoforum.org about sensitizing dyes... http://holoforum.org/forum/viewtopic.php?f=9&t=494

    Some of the links to various dye companies seem like good bets for obtaining these dyes.

    http://www51.honeywell.com/sm/specia...zers.html?c=23
    http://www.corchim.ru/catalog/Phot-sen_PH.html (google translated, here)
    http://www.organica.de/en/download/1...cification.pdf (it's interesting; this dye is sold at HW Sands, but as a functional laser dye, not necessarily advertised as a red sensitizer as it is at this website.)
    If you are the big tree, we are the small axe

  4. #134
    holmburgers's Avatar
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    Review of Literature for Sensitizing Dyes

    Ok, this is a work in progress, but this is the result of some armchair research I've done through, primarily, Google Books. It's a smattering of information relating to sensitizing dyes, and particularly those pre-1930ish.

    Please download the word file for links, some quotations and a better sense of the context.

    I don't claim to be making any conclusions here, but am rather just trying to get a base of information together. I recommend that people go through the links themselves and lets start discussions on certain topics. On the other hand, I don't know if we can conclude too much without some actual testing, but all this literature will certainly point us in the right direction and give us things to consider. In particular, some of the large reference lists should be very valuable for anyone wanting to go deep.

    A lot of the literature is relating to bath sensitizing, much of which is done for astrophotography. There appear to be several contradicting statements in the various sources, so be careful in jumping to conclusions. Lastly, I've undoubtedly missed sources and indeed, haven't claimed to do an exhaustive search. I would simply search "pinacyanol", "orthochrome", or other dye names in Google books and follow the links which looked promising.

    Here is a fairly complete list of all the sensitizers that are mentioned, posted mainly for the purpose of keyword searches. It'd be best to read the literature for broader context and use of the dyes . . . . .

    Earliest Survey after Vogel:
    - Ethyl Violet (triphenylmethane dye) - "red sensitizer for collodion"
    - Eosin, Erythrosin, Rose Bengal (pyronine dyes) - "green and yellow sensitizers"
    - Fast Red, Congo Red, Glycine Red, BenzoNitrol Brown (azo dyes)
    - Acridine Orange, Alizarin Blue

    Cyanine, a.k.a. quinoline blue
    - 1,1'-Di-n-amyl-4,4'-cyanine iodide

    In 1903, Miethe & Traube patented Ethyl Red (an isocyanine).
    - 1,1'-Diethyl-2,4'-cyanine iodide
    - sensitizer for green, yellow and orange
    - a.k.a. chinaldin-ethyl-cyanin

    In 1905, Homolka at Hoechst Dye Works discovered Pinacyanol.
    - 1,1'-Diethyl-2,2'-carbocyanine iodide (or bromide, or chloride)
    - Structure wasn't elucidated until mid-20's through research by Pope.

    Dicyanine and Dicyanine A were manufactured later by Hoechst.
    - 1,1'-Diethyl-2,4'-carbocyanine iodide (dicyanine)
    - 6,6'-Diethoxy-1,1'-diethyl-2,4-carbocyanine iodide (dicyanine A)

    Woolblack – a red sensitizer for gelatin
    Pinaverdol - a green sensitizer

    Orthochrom T
    Pinachrom (pinachrom violet (?))
    Homocol
    Pinaflavol

    Kryptocyanine (1919), Neocyanine (1925), Xenocyanine & other tricarbocyanines (1931) - IR sensitizers

    In summation, Pinacyanol, the most important sensitizer for the red, was used in all panchromatic materials until the thirties. Although by itself it gives fairly good sensitivity in the green in addition to its major contribution in the red, it was usually employed in conjunction with other dyes such as Orthochrome T, Pinaverdol, or pinachrome which conferred greater response in the green.”
    Attached Thumbnails Attached Thumbnails Photographic Sensitizing Chart of Progress.JPG  
    Attached Files
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  5. #135
    holmburgers's Avatar
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    Thanks Umut for the kind words. I didn't notice that about the autochrome screen, that's very interesting indeed.

    I agree that Ukraine prices are probably very desirable.

    Ciao!
    If you are the big tree, we are the small axe

  6. #136
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    How relevant are sensitizing dyes used for solar cells? A lot of research is going on. For example:

    Here we report on the sensitization of semi-
    conductor particles (TiO2 ) by organic dyes such
    as xanthenes (rhodamine 101, fluorescein and 5(6)-
    carboxyfluorescein) and azo dyes (alizarin yellow R,
    alizarin yellow 2G and carboxyarsenazo). Photostabil-
    ity of these dyes will be determined for possible use
    as sensitizers for the nanocrystalline solar cell. The
    role played by redox couple (e.g. I3 − /I− ) electrolyte
    in regenerating the neutral sensitizer dye molecules,
    and thus, stabilization of the dye molecule will be also
    studied. The chosen dyes possessing carboxylate or
    hydroxyl function groups that enable direct interaction
    with the surface of TiO2 particles, thereby providing
    a path for electron transfer from the excited dye
    adsorbate to the semiconductor.....
    From "The interaction and photostability of some xanthenes and selected azo sensitizing dyes with TiO2 nanoparticles", D. EL Mekkawi and M. S. A. Abdel-Mottaleb

    Also, US Patents 4173478 and 4476220 discuss azo dyes as silver halide photographic sensitizers. They do discuss heat processed materials, though.
    Last edited by kb3lms; 07-24-2012 at 08:40 AM. Click to view previous post history. Reason: Added informtation
    All this has happened before, and all this will happen again.

  7. #137
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    TiO2 is quite light sensitive and can be spectrally sensitized. It also has a rather broad sensitivity to radiation and can capture radiation outside of the visible region.

    Images captured with TiO2 are usually printed using digital means and thus this material is outside of our scope here.

    Kodak had a full color system based on TiO2 in the '70s.

    PE

  8. #138
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    I think it's this thread, several posts back, in which Bob Crowley brings up photovoltaic-cell dyes.

    It's interesting to go back to the 1st post and look at the Eastman Kodak Chemicals list that PE posted; several of those dyes are in the historic literature. It also has the chemical structures of some of the dyes, i.e. Orthochrome T.
    If you are the big tree, we are the small axe

  9. #139
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    Just as an FYI, Ethyl Red (off the OP list) is available at Alfa Aesar http://www.alfa.com/en/GP100w.pgm?DS...CAS=76058-33-8 for a fairly reasonable price. The nice lady who got back to me told me that shipping ought to be about $10.

    They will only ship to a business address.
    All this has happened before, and all this will happen again.

  10. #140
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    Also, the second one on the list, 1,1'-Diethyl-2,2'-carbocyanine iodide is available from Alfa Aesar as well http://www.alfa.com/en/gp100w.pgm?dsstk=H31540. That one looks like an infrared dye according to the list.
    All this has happened before, and all this will happen again.



 

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