Polyaniline as Transparent Carrier Injection Electrode Compatible with Low Temperature Poly(p-Pheniline Vinylene) Conversion Process

Travain, Silmar Antonio; Libardi, Luiz; Marletta, Alexandre; Giacometti, J.A.; Guimarães, Francisco Silveira; Faria, Roberto Mendonça

doi:10.1080/713738250

Cited by 6 publications

(5 citation statements)

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“…Between 450 and 700 nm, the 60 nm POMA layer practically does not absorb, thus forming a ''window'' for PPV emission. For comparison, we show the absorption spectrum for a 180 nm PAni film deposited in situ 10,29 and the emission spectrum of a spin-coated poly͓2-methoxy-5-(2Ј-ethylhexyloxy͒-1,4-p-phenylene vinylene͔ ͑MEH-PPV͒ film. 29 The optical window for PAni, from 475 to 600 nm, is narrower than for the POMA film, leading to a larger overlap in the low energy region with PPV emission.…”

Section: Resultsmentioning

confidence: 99%

“…This has been shown in several instances, as follows: ͑i͒ A LBL PPV film coating a POMA layer has a wider window for emission than that reported for PAni layers in previous work. 10 ͑ii͒ When POMA is adsorbed onto ITO, the barrier height for hole injection is decreased. ͑iii͒ The electrical properties of the POMA layer can be preserved at high temperatures when a PPV film is deposited.…”

Section: Discussionmentioning

confidence: 99%

“…9 where a high conductivity was obtained for the POMA layer at high temperature, which indicates that the ITO/ POMA interface is more thermally stable than the ITO/PAni interface. 10,36 The lower 3 indicates that the combination of an ITO/POMA electrode with the codoping process with DBS, at low conversion temperatures, produces fewer structural defects and reduces the dedoping process of the POMA layer. On the other hand, the POMA layer performs as a protecting layer on the ITO substrate, with less chemical attack of the acid produced in the PPV conversion.…”

Section: ͑1͒mentioning

confidence: 99%

“…8 Such a difficulty can be obviated with the use of a low-temperature conversion procedure for PPV, in which the counter-ion Cl Ϫ of PTHT is replaced by the dodecylbenzenesulfonate ͑DBS͒ ion. 9 This low-temperature conversion was used to fabricate ITO/PAni/PPV-DBS/Al structures, 10 where a decrease of ϳ30% was observed in the LED operating voltage. It opens up, therefore, the possibility of using PPV in heterostructures with other less thermally stable polymers, with the added advantage of a higher emission efficiency due to the smaller generation of structural defects ͑carbonyl groups͒ in the PPV converted at lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced optical and electrical properties of layer-by-layer luminescent films

Marletta

Piovesan

Dantas

et al. 2003

Journal of Applied Physics

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The electrical and optical properties of luminescent films from poly(p-phenylene vinylene) (PPV) and poly(o-methoxyaniline) (POMA) produced via the layer-by-layer technique are reported. POMA layers were obtained in a nonself-limiting process from its emeraldine salt. PPV was thermally converted from the precursor poly(xylylidene tetrahydrothiophenium chloride) with sodium dodecylbenzenesulfonate (DBS) at low temperatures of ∼110 °C and short times (∼30 min). The line shape of absorbance and photoluminescence (PL) is not affected with the PPV conversion reaction. High thermal stability of PPV was observed, with the integrated PL decreasing only 10% when the temperature was increased from 10 to 300 K. This decrease was accompanied by a small blue shift of 5 nm in the zero-phonon peak and a low electron–phonon coupling with a Huang–Rhys factor S<1 in the vibration spectral region. The combination of POMA and indium–tin–oxide (ITO) as transparent electrode and PPV+DBS as active layer (ITO/POMA/PPV+DBS/Al) leads to a decrease of 70% in the operating voltage compared with the conventional polymer light emitting-diode ITO/PPV/Al, which means that the POMA layer plays a protective role for the ITO electrode. Furthermore, the POMA layer has its electrical characteristics preserved at high temperatures, with the assistance of a codoping process from acid diffusion from the PPV/DBS layers.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: ͑1͒mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhanced optical and electrical properties of layer-by-layer luminescent films

Marletta

Piovesan

Dantas

et al. 2003

Journal of Applied Physics

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“…We seek for optimized conditions for in situ deposition of PAni films that may lead thin films with desirable thicknesses ranging from a few nanometers to around 200 nm. We show that films with thicknesses as low as ∼25 nm could be prepared by the in situ technique which could be used, for example, as hole injecting layer in electroluminescent devices [24][25][26][27]. In order to investigate the growth process, we analyze the adsorption kinetics for the film fabrication using atomic force microscopy and UV-vis spectroscopy.…”

Section: Introductionmentioning

confidence: 99%