Phosphorescence Energies of Organic Light-Emitting Diodes from Spin-Flip Tamm-Dancoff Approximation Time-Dependent Density Functional Theory

ChemPhysChem ◽  
2011 ◽  
Vol 12 (17) ◽  
pp. 3331-3336 ◽  
Author(s):  
Michael Kühn ◽  
Florian Weigend
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Time Dependent ◽  
Functional Theory ◽  
Light Emitting ◽  
Organic Light ◽  
Spin Flip ◽  
Dependent Density

scholarly journals Theoretical Investigation on Electronic Structure and Photophysical Properties of a Series of Mixed-Carbene Cyclometalated Iridium(III) Complexes With Different Ancillary Ligand Applied in Phosphorescent Organic Light-Emitting Diodes

2021 ◽  
Author(s):  
Tong Chen ◽  
Deming Han ◽  
Lihui Zhao ◽  
Bao Wang ◽  
Xiaohong Shang
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Light Emitting Diodes ◽  
Photophysical Properties ◽  
Organic Light Emitting Diodes ◽  
Ancillary Ligand ◽  
Functional Theory ◽  
Light Emitting ◽  
Organic Light

Abstract By using density functional theory (DFT) and time-dependent density functional theory (TDDFT), the geometrical structure, electronic structure and photophysical properties of a series of mixed-carbene cyclometalated iridium(III) complexes with different ancillary ligand have been explored. The frontier molecular orbital (FMO) components and energy levels for all studied complexes have been investigated. The lowest lying absorptions were calculated to be at 327, 322, 333, 332 and 332 nm for these complexes, which have the transition configuration of HOMO→LUMO. The lowest energy emissions for these complexes are localized at 413, 399, 498, 418 and 415 nm, respectively, simulated in CH2Cl2 medium at the M062X level. One complex designed could possess the largest radiative decay rate (kr) value and be a potential candidate for blue emitters in organic light-emitting diodes (OLEDs). The theoretical study can provide a useful guidance for design and synthesis of new iridium(III) complexes in phosphorescent materials.

Theoretical Study of the Electronic Structure and Properties of Alternating Donor-Acceptor Couples of Carbazole-Based Compounds for Advanced Organic Light-Emitting Diodes (OLED)

2019 ◽  
Vol 824 ◽  
pp. 236-244
Author(s):  
Suppamat Makjan ◽  
Malinee Promkatkaew ◽  
Supa Hannongbua ◽  
Pornthip Boonsri
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Light Emitting Diodes ◽  
Functional Theory ◽  
Light Emitting ◽  
Organic Light ◽  
Hole Transporting ◽  
Photorefractive Materials ◽  
Donor Acceptor

Generally, it is difficult to generate a high-performance pure blue emission organic light-emitting diode (OLED). That is because the intrinsically wide band-gap makes it hard to inject charges into the emitting layer in such devices. To solve the problem, carbazole derivatives have been widely used because they have more thermal stability, a good hole transporting property, more electron rich (p-type) material, and higher photoconductivity. In the present work, novel copolymers containing donor-acceptor-acceptor-donor (D-A-A-D) blue compounds used for OLEDs were investigated. The theory of the geometrical and electronic properties of N-ethylcarbazole (ECz) as donor molecule (D) coupled to a series of 6 acceptor molecules (A) for advanced OLEDs were investigated. The acceptors were thiazole (TZ), thiadiazole (TD), thienopyrazine (TPZ), thienothiadiazole (TTD), benzothiadiazole (BTD), and thiadiazolothienopyrazine (TDTP). The ground state structure of the copolymers were studied using Density Functional Theory (DFT) at B3LYP/6-31G(d) level. Molecular orbital analysis study indicated 3 investigated copolymers (ECz-diTZ-ECz, ECz-diTD-ECz, ECz-diBTD-ECz) have efficient bipolar charge transport properties for both electron and hole injection to the TiO2 conduction band (4.8 eV). In addition, the excited states electronic properties were calculated using Time-Dependent Density Functional Theory (TD-DFT) at the same level. Among these investigated copolymer ECz-diTZ-ECz and ECz-diTD-ECz showed the maximum absorption wavelengths (λabs) with blue emitting at 429 and 431 nm, respectively. The results suggested that selected D-A-A-D copolymers can improve the electron- and hole- transporting abilities of the devices. Therefore, the designed copolymers would be a promising material for future development of light-emitting diodes, electrochromic windows, photovoltaic cells, and photorefractive materials.

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