Analysis of electroluminescence degradation for organic light-emitting diode using a rate equation of chemical kinetics

Figures & data

Table 1. OLED devices with the structure features used in the lifetime experiments.

OLED type	Structure
Double layer	ITO/NPB (60 nm)/ALQ3 (75 nm)/Mg
	+ Ag [10%] (120 nm)/SiO (180 nm)
Hole-block layer	ITO/CuPc (15 nm)/NPB (60 nm)/ALQ3
	(75 nm) [10%] (120 nm)/SiO
	(180 nm)
Doped emitting layer	ITO/NPB(60 nm)
	(1%) (75 nm) [10%](120 nm)/
	SiO (180 nm)

Figure 1. (a) Relative light intensity with fitting curves and (b) respective residues of fitting curves for double-layer OLED at 22°C (□) and 70°C (▵).

Figure 2. (a) Relative light intensity with fitting curves and (b) respective residues of fitting curves for hole-block layer OLED at 22°C (□) and 70°C (▵).

Figure 3. (a) Relative light intensity with fitting curves and (b) respective residues of fitting curves for doped emitter layer OLED at 22°C (□) and 70°C (▵).

Table 2. Kinetics parameters and the calculated and experimental half-lifetimes for the OLED.

	Temperature				t1/2 (h)	t1/2 (h)
OLED type	(°C)	K × 10^−10	n	Θ0 (Cd/m^2)	[regression]	[experiment]
DL-OLED	22	3.95	4.03	809	9.20	10.4
	70	270	3.25	535	44.6	43.5
HBL-OLED	22	23.9	3.16	880	280	268
	70	2.30	3.84	647	95.0	81.0
DEL-OLED	22		6.90	880	29.1	26.2
	70	846	3.16	887	7.97	8.10

Figure 4. Linear fitting for estimating the OLED half-lifetimes using the 1/f lifetime equation (12). (■) HBL-OLED (22°C), (□) HBL-OLED (70°C); (▲) DEL-OLED (22°C), (▵) DEL-OLED (70°C); and (•) DL-OLED (22°C), (gcirc) DL-OLED (70°C).

Table 3. Kinetics parameters obtained from fractional relative light intensity using 1/f=3/4.

OLED	Temperature (°C)	Intercept	Slope	n		t1/2 (h)
DL-OLED	22	8.4	−2.8	3.7	17.9	10.7
DL-OLED	70	6.7	−2.1	3.1	777	41.7
HBL-OLED	22	7.8	−2.0	3.0	64.5	298
HBL-OLED	70	10.9	−3.4	3.9	1.67	83.3
DEL-OLED	22	17.3	−5.8	6.8		31.8
DEL-OLED	70	6.8	−2.2	3.2	573	8.05