The effects of oxygen on charge transport in PDATS

Abstract

AbslracLWe examine the effect oxygen conlamination has on the recombination centre separation, trap density and defect ionization efficiency in PDATS single cryslals. We find that, wilh no Oxygen present, recombination centres are not delecled in sample lenglhs of up lo 9.8 mm. However. for chase samples contaminated with oxygen. we find interQenlre separations of only a few hundred microns. We also show that oxygen increases the trap density and t h e defeci ionization efficiency. Finally, we demonslrale that by aclivating the oxygen presenl in lhe crystals, the recombinalion centre separalion can be further reduced.

Construction and Characterization of [1,6-Di(N-carbazolyl)-2,4-hexadiyne] Diacetylene Polymer Bicrystals

“…Diacetylene polymers are quasi-one-dimensional photoconductors. The photoinduced electrical carrier mobility along the polymer chain direction has been measured to be about 5 cm 2 /V·s , and is 3−4 orders of magnitude higher than that perpendicular to the polymer chain direction. Diacetylene polymers have been utilized to study carrier motion along the chain in semiconductive conjugated polymer solids.…”

“…This process is weak and thus the dissipation by the SWAP is also weak. However, Fisher found that carrier velocity is dependent on the electrical field at low field but tends to be saturated at 5000 m/s at electrical fields higher than 6.5 × 10 4 V/cm . He accordingly suggested that carrier motion along a chain may be that of the SWAP, but the observed motion is dominated by field-dependent trapping events at low fields.…”

“…The time-of-flight technique has proven useful to examine charge carrier drift mechanisms in photoconductors. It has also been used to study electrical transport mechanisms in diacetylene polymer single crystals. ,,− ,, …”

“…However, Fisher found that carrier velocity is dependent on the electrical field at low field but tends to be saturated at 5000 m/s at electrical fields higher than 6.5 × 10 4 V/cm. 43 He accordingly suggested that carrier motion along a chain may be that of the SWAP, but the observed motion is dominated by fielddependent trapping events at low fields. Based on the concept of the SWAP, he assumed the presence of "shallow" Coulomb trapping which is temperature dependent and inversely proportional to the electrical field.…”

“…It has also been used to study electrical transport mechanisms in diacetylene polymer single crystals. 43,45,[47][48][49]52,53 In our studies, the Auston gap transmission line geometry was used due to the flexibility of making micrometer-sized gaps. In an Auston gap transmission line, two electrodes are pasted or deposited on the tested surfaces.…”