The design and synthesis of 1-phenylimidazo[1,5-a]pyridine – anthracene-based fluorophore for greenish-yellow organic light emitting diode and warm white LED

Figures & data

Figure 1. Chemical structure of the synthesized fluorophore.

Figure 2. Optimized molecular geometry, HOMO/LUMO energy levels, and electrostatic potential map of ImPy-Ac.

Scheme 1. Synthetic route of ImPy-Ac.

Figure 3. TGA curve and DSC curve under the N₂ atmosphere of the fluorophore.

Figure 4. ORTEP diagram of the ImPy-Ac.

Figure 5. Single molecular geometry (a) and molecular packings with the views from X-axis (b), Y-axis (c), and Z-axis (d) of ImPy-Ac crystal.

Figure 6. UV-vis spectra in dilute THF solution (10⁻⁵ M) (b) Diffuse reflectance spectra (DRS) measured using a solid compound.

Figure 7. PL spectra of (a) ImPy-Ac solution in THF (10⁻⁵ M), (b) solid ImPy-Ac (c) Thinfilm.

Table 1. Photophysical properties of ImPy-Ac.

Solution		Solid	Thinfilm	Quantum yield	Lifetime (ns)
λabs (nm)	λems (nm)	λems (nm)	λems (nm)
245,300	549	558	553	74%	2.31

Table 2. Electrochemical properties of ImPy-Ac.

Compound	${\mathit{E}}_{\mathit{r}\mathit{e}\mathit{d}}^{\mathit{onset}}$	${\mathit{E}}_{\mathit{o}\mathit{x}}^{\mathit{onset}}$	HOMO (eV)	LUMO (eV)	Energy gap (ΔE, eV)
ImPy-Ac	−0.81	+0.62	−5.02	−3.59	1.43

Figure 8. Absorption and emission spectra of ImPy-Ac in different solvents and CIE coordinates.

Figure 9. Cyclic voltammograms of ImPy-Ac.

Table 3. Electroluminescent performance of ImPy-Ac.

			@100/1000 cd m^–2
Dopant	Device	Dopant [wt.%]	OV[V]	PE[lm W^–1]	CE[cd A^–1]	EQE [%]	CIExy coordinates	Maximum Luminance (cd m^–2)
ImPy-Ac	ΙII-1	1	6.0/7.7	1.2/0.8	2.6/2.2	0.9/0.8	(0.32, 0.46)	1766
	ΙΙI-2	3	7.0/8.2	2.2/2.0	4.9/5.6	3.2/1.4	(0.34, 0.45)	1856
	ΙΙI-3	5	7.5/8.5	1.5/1.1	3.8/3.1	1.5/1.4	(0.33, 0.46)	2331
	III-4	100	4.2/-	0.2/-	0.2/-	0.3/-	(0.32, 0.58)	677

Figure 10. EL spectra and CIE Coordinate of fabricated white LED.

Figure 11. Schematic diagram of ImPy-Ac-based yellow OLED with energy level diagram and chemical structure of materials used.

Figure 12. (a) current density vs voltage (b) luminescence vs voltage (V) (c) current efficiency (cd A^–1) vs luminescence (cd m^–2) (d) Power efficiency (lm W^–1) vs luminescence (cd m^–2).

Figure 13. Electroluminescence spectra of ImPy-Ac.