Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 4

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Space Charge Limited Currents in Anthracene Crystals under Modulated Illumination

100%
Uzarczyk A., Godlewski J.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 4-5
849-854
EN
Space charge limited currents have been examined in anthracene crys­tals illuminated with a chopped beam of monochromatic light (λ = 420 nm). The beam was uniformly absorbed in the anthracene crystal. The primary objective of our research was to determine mechanisms responsible for the release and trapping of charge carriers in the case of space charge limited currents as a function of time. The experimental results concern the depen­dences of photocurrents on the frequency of light chopping, light intensity, voltage and current decay after illumination. Photocurrent decay as a func­tion of time was exponential for short time periods (i.e. for milliseconds), while for longer periods it was described by the power function t^{-1/l}, where parameter 1 is the characteristic parameter of the exponential distribution of traps.
2
Content available remote

Numerical Analysis of Photoenhanced Electric Currents in Molecular Materials

81%
Jarosz G., Signerski R., Godlewski J.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 4-5
855-860
EN
This paper presents numerical calculations of photoenhanced current-applied voltage and photoenhanced current-light intensity characteristics with regard to the exciton diffusion length, lifetime of excitons and rate of exciton surface quenching. Dependencies of this type cannot be obtained an­alytically. It is shown that the increase in diffusion length causes the decrease in current in the case of strong surface quenching of excitons. Simultaneously, it is shown that the quality of crystals influences the photoenhanced current. A better quality of crystals causes the increase in the current in the case of weak surface quenching of excitons.
3
Content available remote

Electric Current Flow through Tetracene Layer-Anthracene Crystal Junction

81%
Signerski R., Godlewski J., Sodolski H.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 4-5
843-847
EN
Theoretical and experimental analysis was carried out on electric cur­rents limited by the potential barrier governing the flow of holes from the tetracene layer to the anthracene crystal. Theoretical spatial distributions of charge carriers near the barrier were determined, as well as current-field dependences for the currents flowing through the investigated junction in the presence and in the absence of illumination. A current-field character­istic of the junction conditioned current is described by dependence of the j ∝ E³_{0} type in the presence of illumination and by the j ∝ E^{2l+1}_{0} type in the lack of illumination, where l is the characteristic parameter of the trap distribution. Experimental research of the hole currents flowing through the polycrystalline tetracene layer-anthracene monocrystal junction confirmed the theoretical predictions about the current-field characteristics. A remark­ably unequivocal confirmation was obtained for the current-field dependences in the presence of illumination.
4
Content available remote

Charge Carrier Generation Caused by X-Rays in Organometallic Materials

71%
Godlewski J., Signerski R., Jarosz G., Stizza S., Berrettoni M.
Acta Physica Polonica A
|
1999
|
vol. 96
|
issue 2
295-301
EN
Organometallic compounds play an exceptional role among organic compounds. Due to their structure a number of these compounds demonstrate interesting properties in various phenomena. Organometallic compounds show special properties in the case of X-ray absorption owing to considerable differences between the absorption coefficients of metals and light elements. The analysis of processes of charge carrier generation as a result of X-ray absorption in chosen organometallic compounds is the subject of this paper. Spectral dependences of charge carrier photogeneration efficiency around the Cu K-edge in copper phthalocyanine and copper acetylacetoniane have been specially considered. It has been observed that the photocurrent spectrum in these materials follows the absorption spectrum but mutual relation is not directly proportional. Experimental results connected with current-voltage and current-intensity characteristics have been analysed, as well. The obtained relationships have been compared with adequate results connected with charge carrier photogeneration in visible area and UV in organic materials. It has been observed that the X-ray photogeneration of charge carriers in the examined range of energy differs from the mechanisms of charge carrier generation in visible area and UV. The basic differences arise from the participation of secondary electrons, which are generated due to Auger electrons, Compton effect, and metal fluorescence. The process of charge carrier generation as a result of X-rays absorption is characterized by strong recombination of charge carriers in channels in which charge carriers are generated by high energetic secondary electrons.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.