Effect of Caesium Based Compounds As Electron Injection Layer In Fluorescent Polymer Organic Light-Emitting Diode

Publication Issue: 
Volume 39, Issue 1, 2018
Page No: 
Date Received: 
Monday, November 13, 2017
Authors' Name: 
Calvin Yi Bin Ng
Kai Lin Woon
Authors' Affiliation and Address: 
Physics Department, Faculty of Science, Low Dimensional Material Research Centre (LDMRC), University of Malaya, 50603 Kuala Lumpur, Malaysia
Electron transport in light emitting semiconducting polymers is often limited by traps. By studying the role of Caesium carbonate (Cs2CO3), Caesium Nitride (CsN3), Caesium Fluoride (CsF) are chosen as the electron injection layer, it is discovered that CsF has the ability to reduce the electron traps followed by CsN3 and then Cs2CO3 with trap density of 1.5 x 1018 cm-3 , 2.22 x 1018 cm-3 , 3.03 x 1018 cm-3 , respectively. We also found out that for such materials, charge balance as often obtained from comparison between electron and hole only devices, is not a good predictor for current efficiency. In fact, highest efficiency is obtained using Cs2CO3 with 11.9 lm/W for superyellow poly-(p-phenylenevinylene) at 1000 cdm-2.
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