Organic Light-Emitting Transistors Based on Pentacene and 4,5-Di(9H-carbazol-9-yl)phthalonitrile Doped onto 1,3-Bis(N-carbazolyl)benzene

Abstract

In this study, multilayered, organic-based lightemitting transistors (OLETs) were produced and characterized. The neutral cluster beam deposition method was applied to successively deposit organic semiconducting layers of pentacene, 4,5-di(9H-carbazol-9-yl)phthalonitrile (2CzPN) doped onto 1,3bis(N-carbazolyl)benzene (mCP), and 1,3,5-tris(1-phenyl-1Hbenzimidazol-2-yl)benzene (TPBi) as the hole-transport, emissive, and electron-transport layers, respectively. The effects of drain electrodes (Au or Li/Al) and TPBi on the device performance were examined under ambient conditions. The bilayered pentacene (bottom, 50 nm)/mCP:2CzPN (top, 50 nm) and trilayered pentacene (bottom, 50 nm)/mCP:2CzPN (middle, 50 nm)/TPBi (top, 10 nm) OLETs demonstrated both electrical switching functionality and control of electroluminescence (EL) in air. In particular, the EL intensity (I EL ) was significantly enhanced in the asymmetric bilayered devices adopting a low work function Li/Al drain electrode owing to the lower electron injection barrier. The operating light emission mechanisms responsible for the observed EL and recombination zone were discussed with the aid of photographic images provided by a charge-coupled device camera.

Organic Light-Emitting Transistors: From Understanding to Molecular Design and Architecture

“…Multilayered OLETs built on a top contact geometry were investigated by Kim et al They used pentacene and phthalonitrile connected fluorene derivative 59 doped on another dicarbazole derivative 60 as the p-channel and emissive layers in a bilayer architecture and compared it with an added third layer of benzimidazol-based compound 61 as an electron transport layer (Figure ). The dopant 59 is a known blue fluorophore.…”

“…Therefore, by using suitable electroluminescent semiconducting materials along with appropriate photochromic materials, the light-emitting proper-ties of the transistors can be efficiently switched over the entire visible region. 98 Multilayered OLETs built on a top contact geometry were investigated by Kim et al 99 They used pentacene and phthalonitrile connected fluorene derivative 59 doped on another dicarbazole derivative 60 as the p-channel and emissive layers in a bilayer architecture and compared it with an added third layer of benzimidazol-based compound 61 as an electron transport layer (Figure 6). The dopant 59 is a known blue fluorophore.…”

Optimizing Strategy for Charge Injection in the Single‐Emitting‐Layer Light‐Emitting Transistor

“…[11] Some researchers accomplished LETs with symmetrical electrodes by introducing transport and modification layers in the device structure, which certainly involved a more complicated fabrication process. [8,[12][13][14] In these devices, multiple functional layers such as the charge transporting layer are used.…”

Ion Effects on the Performance of the Single‐Layer Organic Light‐Emitting Devices Based on Adding Salt Additives

“…In the ionic transition‐metal‐complex LECs (iTMC–LECs), the luminescent material is a small iTMC. [ 3 ] The main difference between the two LECs is that for the former the unique device characteristics are attributed to electrochemical doping while for the latter those are due to “ion space charge” effects. [ 4 ] Due to electrochemical doping, the former device is more insensitive to the electrode work function and the thickness of the active layer but also has a significantly shorter lifetime and slower turn‐on speed compared with the latter one.…”