Exploration of OLED structures for high-resolution microdisplays with enhanced efficiency and color gamut

Figures & data

Figure 1. OLED structures for high-resolution microdisplay according to OLED manufacturing technology.

Figure 2. Electroluminescent spectrum of red, green, and blue emission in OLEDs with a structure of (a) str_CF, (b) str_MC, (c) str_MC_CF1, and (d) str_MC_CF.

Table 1. CIE color coordinate and color gamut according to OLED structures.

Structure		CIEx	CIEy	Color gamut (%) (based on BT.2020)
str_CF	B	0.138	0.056	79.6
	G	0.187	0.716
	R	0.678	0.322
str_MC	B	0.144	0.071	74.9/78.9
	G	0.159	0.739
	R(first)/R(second)	0.624/0.654	0.295/0.34
str_MC_CF1^a	R(first)/R(second)	0.692/0.682	0.308/0.317	85.6/83.4
str_MC_CF3	B	0.141	0.049	97.3
	G	0.136	0.787
	R	0.698	0.302

^a It is assumed that the CIE coordinate for blue and green is the same as that of str_MC.

Figure 3. CIE color coordinates of fabricated OLED devices.

Table 2. Current efficiency according to OLED structures at a current density of 5 mA/cm².

	Current efficiency (cd/A)
Structure	B	G	R
str_CF	0.12	1.14	0.75
str_MC	0.29	5.40	4.91 (first cavity) 3.71 (second cavity)
str_MC_CF1			3.17 (first cavity) 2.84 (second cavity)
str_MC_CF3	0.04	0.78	0.63

Figure 4. Electroluminescent spectrum of red, green, and blue emission in tandem OLEDs with a structure of (a) str_MC_CF1 and (b) str_MC_CF3.

Table 3. CIE color coordinate, color gamut, and current efficiency of tandem OLEDs with a structure of str_MC_CF1 and str_MC_CF3.

Tandem Structure		CIEx	CIEy	Color gamut (%) (based on BT.2020)	Current efficiency (cd/A)
str_MC_CF1	B	0.139	0.059	85.7	2.50
	G	0.14	0.731		29.6
	R	0.68	0.32		17.5
str_MC_CF3	B	0.137	0.052	97.9	0.43
	G	0.144	0.792		10.08
	R	0.700	0.300		4.66