Efficient white light-emitting electrochemical cells based on quantum-dot color conversion layers with high EQE >20

• Published in: Dyes and pigments Vol. 229; p. 112301
• Main Authors: Ho, Shao-Ming, Luo, Dian, Chang, Che-Lun, Yang, Zu-Po, Lu, Chin-Wei, Chang, Chih-Hao, Su, Hai-Ching
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2024
• Subjects: Color conversion layers; Ionic transition metal complexes; Light-emitting electrochemical cells; Quantum dots; White light; Ionic transition metal complexes; White light; Light-emitting electrochemical cells; Quantum dots; Color conversion layers
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2024.112301

Solid-state light-emitting electrochemical cells (LECs) offer promising benefits, including simple device architecture, low operating voltage, and insensitivity to electrode work functions. These advantages make them highly suitable for low-cost display and lighting applications, with significant potential for widespread adoption. However, great challenges remain in realizing stable and efficient white LECs. In this work, the blue LECs integrated with red or yellow/red quantum-dot (QD) color conversion layers (CCLs) are shown to achieve efficient and stable white emissions. When the blue LECs are combined with red QD CCLs, they achieve an external quantum efficiency (EQE) exceeding 20 % at a low current density of 0.003 mA cm−2. Alternatively, the blue LECs integrated with yellow/red QD CCLs deliver white emissions with a low CCT <2500 K and a high CRI up to 93 while the peak EQE at a low current density of 0.005 mA cm−2 still remains high (>16 %). The data effectively showcase that efficient and stable white emission can be achieved through partial energy down-conversion from the blue LECs to the QD CCLs, and the proposed white light sources are potential candidates for lighting applications. [Display omitted] •White light sources using blue LECs and red or yellow/red QD color conversion layers.•Peak external quantum efficiencies of the proposed devices are higher than 20 %.•The white EL spectra are stable in a wide range of operating current.