Organic Optoelectronic Devices like OLED (Organic Light Emitting Diode) and OPV (Organic Photovoltaic Device) with a two-dimensional photonic crystal structure have been fabricated by several groups, but not all the opportunities are still exploited and many further steps can be done in this field of optics application. In particular the Photonic Quasi Crystal (PQC) structures are rarely employed and utilized without verify their effective potential. Through PQC structure is possible to enhance more than one optics wavelenght and so they could be very important for large spectra emission sources, i.e. white organic light emission diode (WOLED). In this work we realized many different PQC, octagonal, 12-fould and Thue-Morse, structures using a high-resolution electron beam lithography (EBL) technique. The EBL employed consisted of a Raith 150 system. The samples were obtained by exposing a layer of ZEP (electronic resist) deposited on a highly conductive PEDOT:PSS layer, spin coated onto a Corning glass substrate. A 200-nm-thick layer of colloidal doped ZEP was spin coated on top of the cleaned substrate. The resulting two-dimensional photonic crystal is made of air rods embedded into the organic matrix of ZEP. The ZEP crystal was subsequently used as a lithographic mask during the anisotropic plasma etching process of the underlying highly conductive PEDOT:PSS, which was obtained by doping the PEDOT:PSS with dimethylsulfoxide (DMSO). The plasma etching partially removes the PEDOT:PSS layer, yielding a polymeric photonic quasi crystal onto a polymeric electrode. An optical setup was adopted to evaluate the PQC properties and estimate the WOLED spectral properties. Light propagating in the glass substrate and extracted by diffraction was measured at room temperature. This apparatus has been used to analyze the optical properties of our photonic crystals in order to evaluate the resonances of the structures and the operational optical ranges. In figure is possible to observe the chromaticity diagram (CIE diagram) related to the extracted PQC spectra. It will be also showed the result obtained using the nanostructured electrode within a OLED device and will be examined its effect on the electro-optical properties.

Photonic Quasi Crystal Electrode to be used in the Organic LED: Realization and Characterization

M Rippa;L Petti
2015

Abstract

Organic Optoelectronic Devices like OLED (Organic Light Emitting Diode) and OPV (Organic Photovoltaic Device) with a two-dimensional photonic crystal structure have been fabricated by several groups, but not all the opportunities are still exploited and many further steps can be done in this field of optics application. In particular the Photonic Quasi Crystal (PQC) structures are rarely employed and utilized without verify their effective potential. Through PQC structure is possible to enhance more than one optics wavelenght and so they could be very important for large spectra emission sources, i.e. white organic light emission diode (WOLED). In this work we realized many different PQC, octagonal, 12-fould and Thue-Morse, structures using a high-resolution electron beam lithography (EBL) technique. The EBL employed consisted of a Raith 150 system. The samples were obtained by exposing a layer of ZEP (electronic resist) deposited on a highly conductive PEDOT:PSS layer, spin coated onto a Corning glass substrate. A 200-nm-thick layer of colloidal doped ZEP was spin coated on top of the cleaned substrate. The resulting two-dimensional photonic crystal is made of air rods embedded into the organic matrix of ZEP. The ZEP crystal was subsequently used as a lithographic mask during the anisotropic plasma etching process of the underlying highly conductive PEDOT:PSS, which was obtained by doping the PEDOT:PSS with dimethylsulfoxide (DMSO). The plasma etching partially removes the PEDOT:PSS layer, yielding a polymeric photonic quasi crystal onto a polymeric electrode. An optical setup was adopted to evaluate the PQC properties and estimate the WOLED spectral properties. Light propagating in the glass substrate and extracted by diffraction was measured at room temperature. This apparatus has been used to analyze the optical properties of our photonic crystals in order to evaluate the resonances of the structures and the operational optical ranges. In figure is possible to observe the chromaticity diagram (CIE diagram) related to the extracted PQC spectra. It will be also showed the result obtained using the nanostructured electrode within a OLED device and will be examined its effect on the electro-optical properties.
2015
Istituto di Scienze Applicate e Sistemi Intelligenti "Eduardo Caianiello" - ISASI
Photonic quasi-crystals
Light extraction
OLED
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/297852
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