It is widely known that the external quantum efficiency of conventional organic light emitting diode (OLED) devices is close to 20% because of losses due to wave-guiding effect. Recently, there has been great progress to enhance the light out-coupling efficiency of organic electroluminescent devices by means of various internal and external device modification techniques. One of the best strategies to increase the efficiency factor is related to the use of photonic crystal or photonic quasi-crystal structures [1,2]. In this work we realize photonic quasi crystal patterns directly on the polymeric anode electrode. In particular, we realized and characterized different PQCs polymeric anode (octagonal, dodecagonal and Thue-Morse patterns) to enhance the light emission efficiency of WOLED devices. An optical setup was adopted to evaluate the PQCs polymeric anode properties and estimate the possible spectral modification and emission enhancement of polymeric WOLED devices. 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 structures in order to evaluate the spectral extraction and the operational optical ranges. We demonstrated the possibility to obtain a remarkable efficiency gain using PQCs nanostructures in highly conductive PEDOT:PSS polymer electrode reaching for white light emission an improvement also higher than 60%.
Photonic quasi crystals in White Organic LED applications
Lucia Petti;Massimo Rippa;
2014
Abstract
It is widely known that the external quantum efficiency of conventional organic light emitting diode (OLED) devices is close to 20% because of losses due to wave-guiding effect. Recently, there has been great progress to enhance the light out-coupling efficiency of organic electroluminescent devices by means of various internal and external device modification techniques. One of the best strategies to increase the efficiency factor is related to the use of photonic crystal or photonic quasi-crystal structures [1,2]. In this work we realize photonic quasi crystal patterns directly on the polymeric anode electrode. In particular, we realized and characterized different PQCs polymeric anode (octagonal, dodecagonal and Thue-Morse patterns) to enhance the light emission efficiency of WOLED devices. An optical setup was adopted to evaluate the PQCs polymeric anode properties and estimate the possible spectral modification and emission enhancement of polymeric WOLED devices. 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 structures in order to evaluate the spectral extraction and the operational optical ranges. We demonstrated the possibility to obtain a remarkable efficiency gain using PQCs nanostructures in highly conductive PEDOT:PSS polymer electrode reaching for white light emission an improvement also higher than 60%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
