1064‐nm Sensitive Organic Photorefractive Composites

Abstract

Organic photorefractive composites with sub‐second response time and complete internal diffraction efficiency at low‐intensity 1064 nm illumination are presented. Direct sensitization of the composites is provided by the C84 fullerene derivative [84]PCBM or the organic/inorganic hybrid Ni‐dithiolene complex TT‐2324. Holographic measurements on blends with varying contents of sensitizer are demonstrated.

Organic Photorefractive Materials and Applications

“…Due to the favourable absorbing capabilities in the nearinfrared and the high charge generation effi ciency when doped into hole-conducting polymers, the higher fullerene-derivative [84]PCBM ( 35 ) was successfully capable to sensitize a PF6-TPDbased PR material to achieve high sensitivity under low intensity (1 W cm − 2 ) 1064 nm irradiance. [ 54 ] The results were shown to improve for enhancing the sensitizer content from 1 wt.% to 5 wt.%. The measurements revealed a complete internal diffraction effi ciency ( η = 81% at 60 V μ m − 1 ) and fast response times of τ 5 = 36 ms (regarding the build-up of 5% internal diffraction effi ciency) for 5 wt.% [ 84 ] PCBM.…”

“…[ 54 ] The material featured sub-second response times and complete internal diffraction effi ciency. However, due the high absorption of the sensitizer and its unfavourable infl uence on the trapping landscape and the sensitivity when used in higher concentrations (above 1 wt.%), the performance was inferior to the results described for [84]PCBM sensitized materials in the same publication (see Section 3.3.2.1).…”

“…The higher photocurrent yield, diffraction effi ciency and dynamic performance of SiPc compared to ZnPc was explained Figure 9 . Chemical structure of metal-containing complexes, 41 TT-2324, [ 54 ] 42 ZnPc, [ 123 ] 43 SiPc. [ 123 ] of the PVK/7-DCST-based PR material, which was explained by the reduction of trapping centers originating from a lower density of QD surface defects.…”

“…In both references, no concise connection of the infl uence of the sensitizer on the steady-state PR properties of the materials is described. [ 104 ] 21 TCNQ, [ 104 ] 22 TCNE, [ 104 ] 23 BQ, [ 105 ] 24 MQ, [ 105 ] 25 Cl 2 Q, [ 105 ] 26 Chloranil, [ 105 ] 27 DDQ, [ 105 ] 28 TCNB, [ 105 ] 29 2,5-OMePCBM, [ 47 ] 30 [70]PCBM, [ 47 ] 31 PCBM, [ 47 ] 32 azafulleroid, [ 47 ] 33 F 5 -PCBM, [ 47 ] 34 ketolactam, [ 47 ] 35 [84]PCBM, [47,54] 36 DBM, [100,106,107] 37 TNF-C 60 -dyad with polyether linker, [108,109] 38 -40 TNF-C 60 -Dyads. [ 110 ] Several recent papers were devoted to produce all-organic photorefractives for operation in the region above 830 nm, which allows for NIR applications like biomedical imaging and the processing of telecommunication signals.…”

“…. Chemical structures of hole-conductors employed in photo refractive materials: 1 PVK, [ 62 ] 2 PCzEA, [ 63 ] 3a PVI, [ 60 ] 3b PVDMI, [ 60 ] 4 DBOP, [ 64 ] 5a PSX-Cz, [ 65 ] 5b PSX-bTPA, [ 66 ] 5c PSX-IDEH, [ 67 ] 5d PSX-PhPA, [ 67 ] 6 TFB, [ 68 ] 7 PF6-TPD, [47,54,55,69] 8 TPD-PPV, [70,71] 9 PDAS, [ 72 ] 10 MM-PSX-TAA, [ 73 ] 11 TPDac, [ 74 ] 12 PATPD, [75,76] 13 MDCETPD, [ 77 ] 14 p-PMEH-PPV, [ 78 ] 15 EhCzThThZ, [ 79 ] 16 DiCz. times in the order of seconds under 830 nm illumination and 57 V μ m − 1 .…”