Document Type
Thesis
Date of Award
6-30-1963
Degree Name
Master of Science in Chemical Engineering - (M.S.)
Department
Chemical Engineering
First Advisor
Saul I. Kreps
Second Advisor
George C. Keeffe
Third Advisor
Michael Frederick
Abstract
The purpose of this work was to investigate the field of organic semiconductors and in particular to develop the means for preparing these materials in suitable condition for measurement and study of semiconducting properties. The first aspects of this project concerned with a preliminary survey of the field and techniques of ultra purification are covered in this work.
Anthracene was selected for investigation because it is the organic semiconductor most commonly studied by other investigators, and considerable published information exists for corroboration.
The preliminary survey elucidated the most promising methods of purification, which were chemical synthesis, sublimation, recrystallization from solvents and zone refining. The relative merits of each method were explored and are discussed with particular attention to zone refining which is considered to be the most applicable. High purity anthracene of fluorescent quality was prepared by the tone refining of commercial (95 percent) anthracene and is believed to be adequate for crystal growth and subsequent electrical measurements. Previous workers all started with highly purified anthracene before zoning was attempted.
Quantitative analytical determination of napthacene content was made using a unique technique involving the fluorescence of colloidal solutions of anthracene. Improved sensitivity approaching, 0.1 ppm of napthacene in anthracene, ease of sample preparation, small sample sire and freedom from extraneous effects made this a significant improvement over technicues used heretofore.
Zone refining, has been found to reduce napthacene contents below detectable limits and other impurities whose segregation coefficients are less than unity should be similarly removed. This technique is generally applicable to other solid organic materials which are of interest as semiconductors. The practical considerations in zone refining are discussed in detail including such parameters as ratio of zone length to sample length, refining rate, and number of passes required to achieve an ultimate distribution of impurities. This is of use in operating an optimum refining process.
The segregation coefficient of anthracene from naphthacene was round to be al out 0.6 at a refining rate of 3 in/hr. Calculations showed that 60 zone passes are requirer for ultimate zone reining purification under the experimental conditions employed here. This was confirmed by experiment.
Recommended Citation
Czorny, Bohdan Robert, "The electrical and optical properties of organic semiconductors. Part 1 : Preliminary survey and purification techniques" (1963). Theses. 2775.
https://digitalcommons.njit.edu/theses/2775
