**4.1 Energy diagram of an OLED based on these compounds**

In this part, we attempt to design new organic architecture using the luminescent investigated material as an active layer by the insertion of single-walled carbon nanotubes as shown in **Figure 9**.

First, the anode and cathode must be chosen to facilitate the injection of the free charge carrier from anode or cathode to the active layer (luminescent organic material). **Table 3** presents the traditionally used material and their electronic characteristics parameters (anode output work (ΦA) and the output work of the cathode (ΦC).

By comparing electronic parameters of the investigated material and that of The traditional anode and cathode materials, cathode (Ca, Mg) can better helpfully inject the charge carriers (electron) from the cathode to the synthesized materials. Using


#### **Table 2.**

*Electronic parameters of the optimized chemical structure of SWCNTs (5,5) and SWCNTs (6,4).*

#### **Figure 9.**

*Proposed multilayer structure using the investigated organic material as an emitting layer.*

*Synthesis, Experimental and Theoretical Investigations on the Optical and Electronic Properties… DOI: http://dx.doi.org/10.5772/intechopen.103807*


#### **Table 3.**

*Value of the work function of the possible used cathode and anode.*


#### **Table 4.**

*Electronic parameters of the possible used anode and cathode and the active layer with and without SWCNTs.*

(Ca, Mg) as a chosen cathode in the designed multi-structure layer, and the synthesized materials (PVK-MeT, DMOCN and DBrCN) as an active layer, we calculate the electron injection barrier (ΔEe), which is defined as the energy difference between the energy value of the LUMO of the used photoactive layer and the output work of the cathode (ΦC). The obtained results are summarized in **Table 4**. The insertion of the singlewalled carbon nanotube (SWCNTs) between the cathode and the photoactive layer

greatly reduces the value of ΔEe. The reduction of ΔEe is more important with SWCNTs (5,5) than when using the SWCNTs (6,4) reduction (see **Figure 10**).

Consequently, SWCNTs (5,5) as a layer between the (Ca, Mg) and the investigated photoactive multilayer can helpfully improve the electron injection from the cathode to the active material which improves the performance of The OLEDs based on the designed multi-structure.
