Rational Design of Star-Shaped Molecules with Benzene Core and Naphthalimides Derivatives End Groups as Organic Light-emitting Materials

Ruifa Jin

doi:10.4172/2161-0401.1000134

Abstract

A series of star-shaped molecules with benzene core and naphthalimides derivatives end groups have been designed to explore their optical, electronic, and charge transport properties as charge transport and/or luminescent materials for organic light-emitting diodes (OLEDs). The frontier molecular orbitals (FMOs) analysis has turned out that the vertical electronic transitions of absorption and emission are characterized as intramolecular charge transfer (ICT). The calculated results show that the optical and electronic properties of star-shaped molecules are affected by the substituent groups in N-position of 1,8-naphthalimide ring. Our results suggest that star-shaped molecules with n-butyl (1), Benzene (2), Thiophene (3), thiophene S’,S’-dioxide (4), benzo[c][1,2,5]thiadiazole (5), and 2,7a-dihydrobenzo[d] thiazole (6) fragments are expected to be promising candidates for luminescent and electron transport materials for OLEDs. This study should be helpful in further theoretical investigations on such kind of systems and also to the experimental study for charge transport and/or luminescent materials for OLEDs.

Highlights

Organic light-emitting diodes (OLEDs) have received considerable interest due to their promising applications in the large-area flat-panel displays and solid-state lighting [1,2,3,4,5,6]
In this work, we investigated a series of star-shaped molecules with benzene as core and NI derivatives as end groups for OLEDs applications (Scheme 1)
The origin of the geometric difference introduced by excitation can be explained, at least in qualitative terms, by analyzing the change in the bonding character of the orbitals involved in the electronic transition for each pair of bonded atoms

Summary

Introduction

Organic light-emitting diodes (OLEDs) have received considerable interest due to their promising applications in the large-area flat-panel displays and solid-state lighting [1,2,3,4,5,6]. Since the first report on OLEDs in 1987, the light generation efficiencies of OLEDs have been steadily increased by using novel materials and the different device structures [7,8,9]. Among the various kinds of OLEDs materials, 1,8-naphthalimide (NI) derivatives usually exhibit strong fluorescence and good photostability [12,13,14]. They have been widely used as the most important materials for fabrication of OLEDs. NI derivatives have high electron affinity and excellent transport property due to the existence of an electron-deficient centre. It was found that the devices using these molecules performance are better than using the most prevalent tris(8-quinolinato)aluminum (Alq3) as a counterpart

Methods

Results

Conclusion