High‐Color‐Rendering and High‐Efficiency White Organic Light‐Emitting Devices Based on Double‐Doped Organic Single Crystals

Abstract

Organic single crystals with much higher carrier mobility and stability compared to the amorphous organic materials have shown great potential in electronic and optoelectronic devices. However, their applications in white organic light‐emitting devices (WOLEDs), especially the three‐color‐strategy WOLEDs, have been hindered by the difficulties in fabricating complicated device structures. Here, double‐doped white‐emission organic single crystals are used as the active layers for the first time in the three‐color‐strategy WOLEDs by co‐doping the red and green dopants into blue host crystals. Precise control of the dopant concentration in the double‐doped crystals results in moderately partial energy transfer from the blue donor to the green and red dopants, and thereafter, simultaneous RGB emissions with balanced emission intensity. The highest color‐rendering index (CRI) and efficiency, to the best of the authors' knowledge, are obtained for the crystal‐based WOLEDs. The CRI of the WOLEDs varies between 80 and 89 with the increase of the driving current, and the luminance and current efficiency reach up to 793 cd m−2 and 0.89 cd A−1, respectively. The demonstration of the present three‐color organic single‐crystal‐based WOLED promotes the development of the single crystals in optoelectronics.

High-efficiency crystalline white organic light-emitting diodes

“…WOLED and exciplex WOLED 59 – 62 . A comparison with other WOLEDs based on crystalline materials 7 , 63 is also shown in Fig. S10a–d .…”

Two-Dimensional Organic Semiconductor Crystals for Photonics Applications

“…The 2D organic crystals also function as the emitting layers in OLED devices and realize single crystal based three-color white OLEDs devices. 71 Although the overall performance of the device is far from the traditional organic small-molecule OLEDs, it provides another solution for the achievement of high-color-quality white OLED devices. The interfacial contact, energy alignment, and thickness of single crystal should be optimized to realize more balanced charge transport for higher efficiency of single crystal based OLEDs.…”

“…The 2D organic crystals also function as the emitting layers in OLED devices and realize single crystal based three-color white OLEDs devices . Although the overall performance of the device is far from the traditional organic small-molecule OLEDs, it provides another solution for the achievement of high-color-quality white OLED devices.…”

High Mobility Emissive Organic Semiconductors for Optoelectronic Devices

“…Significant efforts have been made on the research of OLEDs based on single crystal by Ding et al 157,158 They developed a feasible technique of template stripping to tackle with the poor contact between electrodes and crystals shown in Figure 5a. 149 The anode and cathode can be directly deposited on either side of the crystals by thermal evaporation, ensuring efficient carrier injection.…”

“…Their elaborate research illustrates the feasibility of OLEDs based on single crystals and their great potential for a wide practical application. 157 With the high mobility and strong emission properties, the integration of new functions can further expand the application scenarios of the OLEDs. Jia et al reported highly efficient inherent linearly polarized OLEDs with DPA single crystal as intrinsically polarized emitters, and showed the state-of-the-art EQE of 3.38% in single crystal based-OLEDs in Figure 5c, d.…”