Papers by Keyword: Cathode Interfacial Layer

Abstract: We reported enhanced characteristics of the organic solar cells (OSCs) using pyromellitic dianhydride (PMDA) material as cathode interfacial layer. This PMDA cathode interfacial layer was used in a bilayered structure consisting of lithium fluoride (LiF) and pyromellitic dianhydride (PMDA) at the interface of poly(3-hexylthiophene-2,5-diyl)(P3HT)+[6,6]-phenyl C61 butyric acid methyl ester (PCBM) and Al. Better performance enhancement compared to OSCs without a cathode interfacial layer or with a single LiF interfacial layer was achieved by using a bilayered interfacial structure. The OSC with a cathode interfacial structure with LiF and PMDA combination showed 2.08 % power conversion efficiency (PCE) value, while the OSC with a single LiF cathode interfacial layer showed 1.72 % PCE value and the OSC without any cathode interfacial layer showed 1.35 % PCE value, respectively. And Cole-Cole plots of OSCs showed that bilayered interfacial structure reduced impedance probably by improving the electron transport between Al and PCBM+P3HT.

Abstract: We reported characteristics of OLEDs with the metallocene compounds as cathode interfacial layer between the organic layer and the cathode electrode. The brightness and efficiency of OLEDs with the metallocene compound cathode interfacial layer exhibited higher performance than those of OLEDs without it. The enhancements are attributed to an improved balance of hole and electron due to increased electron injection at the organic layer and the cathode.

Abstract: We report the use of nanostructured metal oxides as cathode interfacial layers for improved performance hybrid polymer electronic devices such as light-emitting diodes (PLEDs) and solar cells. In particular, we employ a stoichiometric (WO3) and a partially reduced tungsten metal oxide (WOx) (x<3), both deposited as very thin layers between an aluminum (Al) cathode and the active polymer layer in hybrid PLEDs and achieve improved PLED device performance reflected as an increase in the current density and luminance and a reduction of the operating voltage. On the other hand, we investigate the use of a stoichiometric tungsten oxide layer as a thin cathode interfacial layer in hybrid polymer photovoltaic cells (Hy-PVs). We demonstrate improved photovoltaic cell performance, primarily as a result of the substantial increase in the short-circuit photocurrent. The improved PLED device characteristics are attributed to enhanced electron injection that primarily results from the lowering of the effective interfacial barrier, as evidenced by photovoltaic open circuit voltage measurements, and improved electron transfer. On the other hand, the observed improvement in the hybrid solar cell performance is primarily attributed to its enhanced internal quantum efficiency, most likely due to the improved electron transport and extraction at the active layer/WO3/Al interface and the reduction of the corresponding contact series resistance. Correlation between the metal oxide surface morphology and the device performance is also investigated and will be discussed.