Stimulated triplet–triplet fusion by carrier trap-detrap mechanism in organic light-emitting diodes

Figures & data

Figure 1. The emission process of the conventional TTF device and TTF-AM device.

Figure 2. (a) Energy level diagram of devices and chemical structure of materials, (b) Current density-voltage-luminance (J-V-L), (c) External quantum efficiency (EQE)-current density, and (d) EL spectra at 1,000 cd/m² of the TTF devices.

Figure 3. The transient EL measurement from low to high current density range according to the doping concentration of the TTF-AM (10, 20, and 30 wt%) of the conventional TTF and TTF-AM device: (a) 10, (b) 70, (c) 150 current density and EL intensity^-1/2-time (inset), and (d) EQE-current density (up) and TTF ratio-current density (down).

Figure 4. The transient EL of the conventional TTF and TTF-AM doped (30 wt% doping) devices at voltage pulses of (a) 1, (b) 10, (c) 50, and (d) 100 µs under a current density of 150 mA/cm².

Figure 5. The impedance data of conventional TTF and TTF-AM 30 wt% devices: (a) capacitance-voltage at AC frequency of 50 Hz, 3-D plot of capacitance-frequency-voltage of (b) conventional TTF, and (c) TTF-AM 30 wt% device (light-emitting devices in [a] and hole-only device in [b, c]).

Table 1. Summarized device performances of the TTF devices with 10, 20, and 30 wt% TTF-AM.

	Voltage (V)^a	Current density (mA/cm^2)^a	EQE^a/EQEmax (%)	CIEx^b	CIEy^b
Conventional TTF	5.2	8.1	1.1/2.7	0.15	0.07
TTF-AM_10 wt%	4.6	5.9	2.4/3.1	0.15	0.07
TTF-AM_20 wt%	4.5	6.4	2.5/2.9	0.15	0.07
TTF-AM_30 wt%	4.6	6.3	2.5/2.8	0.15	0.07

^a Values at luminance of 100 cd/m². ^bColour coordinates at a luminance of 1,000 cd/m².