Photorefractive device using self-assembled monolayer coated indium-tin-oxide electrodes

Photorefractive (PR) performances of methyl-substituted poly(triarylamine) (PTAA)-based PR device were demonstrated using chemically modified electrodes (CMEs) of self-assembled monolayer (SAM) coated indium-tin-oxide (ITO) electrodes. The SAM-ITO electrodes successfully suppressed dark current which blocks the formation of space-charge field and also causes the dielectric breakdown. The PR device consisted of composite of PTAA, 4-azacycloheptylbenzylidenemalononitrile (7-DCST), N-ethylcarbazole (ECz), and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) sandwiched between the SAM-ITO electrodes. The PR devices showed the PR performances: optical gain Gamma, refractive index Delta n, diffraction efficiency eta, response time tau, sensitivity S, phase shift Phi, trap-limited field E-q, number density of traps N-T, and space-charge field E-SC. The remarkable response time of 11.3 ms was achieved at the low electric field of 20 V mu m (1), which was comparable to the response time of high-definition television (HDTV) quality of 16 ms. Our approach will widen the usage of higher mobility materials to photorefractive field and give us more favorable materials to achieve the best performance of photorefractivity in the future. (C) 2013 Elsevier B. V. All rights reserved.