1. Highly efficient tandem organic light-emitting diodes using p-type metal halide copper iodide (CuI)
- Author
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Kanghoon Kim, Jae-In Yoo, Hyo-Bin Kim, Sung-Cheon Kang, Jincheol Jang, Sundararajan Parani, and Jang-Kun Song
- Subjects
CuI ,metal halide ,charge generation layer ,tandem ,OLED ,Computer engineering. Computer hardware ,TK7885-7895 - Abstract
Efficient charge generation is essential for tandem organic light-emitting diode (OLED) devices. In this study, we introduce a p-type copper iodide (CuI) layer within the charge generation layer (CGL) that exhibits high charge generation efficiency in tandem OLED devices. Briefly, CuI is deposited as a thin layer via thermal evaporation technique. X-ray diffraction (XRD) analysis reveals the formation of γ-CuI, and the ultraviolet-visible (UV-Vis) spectral analysis demonstrates outstanding optical transparency (∼95%) of the deposited CuI films in the visible range. The current-voltage (I-V) and capacitance-voltage (C-V) analyses show that the p-type CuI layer is a vital and excellent charge generator and enhances the current density significantly. The tandem OLED device fabricated using Bphen:Liq/CuI/HAT-CN as the CGL results in a substantial 1.9-fold increase in current efficiency compared to the single-unit OLED device, approaching the theoretical two-fold increase. These findings highlight the potential of CuI as a promising p-type material for CGL design in tandem OLED devices.
- Published
- 2024
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