Charge carrier photogeneration, trapping, and space-charge field formation in PVK-based photorefractive materials

2000 ◽  
Vol 61 (20) ◽  
pp. 13515-13527 ◽  
Author(s):  
T. K. Däubler ◽  
R. Bittner ◽  
K. Meerholz ◽  
V. Cimrová ◽  
D. Neher
Keyword(s):  
Charge Carrier ◽  
Space Charge ◽  
Space Charge Field ◽  
Photorefractive Materials ◽  
Charge Field ◽  
Field Formation

scholarly journals Photorefractive Conjugated Polymer-Liquid Crystal Composites

1999 ◽  
Vol 597 ◽  
Author(s):  
M. R. Wasielewski ◽  
B. A. Yoon ◽  
M. Fuller ◽  
G. P. Wiederrecht ◽  
M. P. Niemczyk ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Space Charge ◽  
Charge Transport ◽  
Photorefractive Effect ◽  
Space Charge Field ◽  
Mobile Species ◽  
Beam Coupling ◽  
Charge Field ◽  
A Charge ◽  
Field Formation

AbstractA new mechanism for space-charge field formation in photorefractive liquid crystal composites containing poly(2,5-bis(2′-ethylhexyloxy)-l,4-phenylenevinylene) (BEH-PPV) and the electron acceptor N,N′-dioctyl-1,4:5,8-naphthalenediimide, NI, is observed. Using asymmetric energy transfer (beam coupling) measurements that are diagnostic for the photorefractive effect, the direction of beam coupling as a function of grating fringe spacing inverts at a spacing of 5.5 μm. We show that the inversion is due to a change in the dominant mechanism for space-charge field formation. At small fringe spacings, the space-charge field is formed by ion diffusion in which the photogenerated anion is the more mobile species. At larger fringe spacings, the polarity of the space charge field inverts due to dominance of a charge transport mechanism in which photogenerated holes are the most mobile species due to hole migration along the BEH-PPV chains coupled with interchain hole hopping. Control experiments are presented, which use composites that can access only one of the two charge transport mechanisms. The results show that charge migration over long distances leading to enhanced photorefractive effects can be obtained using conjugated polymers dissolved in liquid crystals.

Monte Carlo simulation of trap effects on space-charge field formation

2006 ◽  
Vol 418 (1-3) ◽  
pp. 54-58 ◽  
Author(s):  
Choongkeun Lee ◽  
Mino Yang ◽  
Nam-Soo Lee ◽  
Nakjoong Kim
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Space Charge ◽  
Space Charge Field ◽  
Charge Field ◽  
Field Formation

Memory Effects in Photorefractive Materials

1998 ◽  
Vol 07 (01) ◽  
pp. 47-60 ◽  
Author(s):  
David Statman ◽  
James C. Lombardi
Keyword(s):  
Response Time ◽  
Space Charge ◽  
Memory Effect ◽  
Space Charge Field ◽  
Interaction Length ◽  
Beam Coupling ◽  
Photorefractive Materials ◽  
History Of ◽  
Charge Field ◽  
Dc Component

We have determined that the dynamics of the signal in photorefractive two beam coupling can be described by a memory effect in the writing of the space charge field. Experimental and computational results confirm that this time dependence is dependent on the history of interference pattern responsible for the space charge field. From this memory effect it is shown that if the input signal has a sinusoidal component much smaller than its DC component, the sinusoidal component of the two beam coupled signal is shifted by the response time of the photorefractive medium. We have demonstrated, both theoretically and experimentally, that for the non-depleting pump this response time is linear with the interaction length.

scholarly journals The influence of disorder on the space charge field formation in photorefractive polymers

1996 ◽  
Vol 29 (7) ◽  
pp. 2045-2048 ◽  
Author(s):  
G G Malliaras ◽  
H Angerman ◽  
V V Krasnikov ◽  
G ten Brinke ◽  
G Hadziioannou
Keyword(s):  
Space Charge ◽  
Space Charge Field ◽  
Photorefractive Polymers ◽  
Charge Field ◽  
Field Formation

Correlation between concentration and disorder of doped trap molecules in space charge field formation

2006 ◽  
Vol 422 (1-3) ◽  
pp. 106-110 ◽  
Author(s):  
Choongkeun Lee ◽  
Sun-Kyung Park ◽  
Mino Yang ◽  
Nam-Soo Lee ◽  
Nakjoong Kim
Keyword(s):  
Space Charge ◽  
Space Charge Field ◽  
Charge Field ◽  
Field Formation
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