Affiliation:
1. Department of Electrical and Computer Engineering Inter‐university Semiconductor Research Center and Soft Foundry Institute Seoul National University Seoul 08826 Republic of Korea
2. SKKU Advanced Institute of Nanotechnology (SAINT) School of Nano Science & Technology Sungkyunkwan University (SKKU) Suwon 16419 Republic of Korea
3. Chemistry Division Los Alamos National Laboratory Los Alamos NM 87545 USA
4. Department of Electronics Engineering and Institute of Advanced Materials and Systems Sookmyung Women's University Seoul 04310 Republic of Korea
Abstract
AbstractQuantum dot light‐emitting diodes (QLEDs) are considered promising candidates for several optoelectronic applications; however, they are plagued by the over‐injection of electrons compared to holes, which limits device efficiency. Studies have attempted to reuse the leaked electrons and transfer recombination energies via inserting an exciton‐harvesting layer (EHL) between the emissive layer (EML) and hole transport layer (HTL). This study conducts a detailed analysis of the energy transfer mechanisms to obtain better insights into improving the device performance. First, by analyzing the electroluminescence (EL) spectra and exciton dynamics, the effect of EHLs comprising phosphorescence (PH) or thermally activated delayed fluorescence (TADF) blue dopant is compared. Through parallel incorporation of those EHLs on QLEDs and organic LEDs, the minimal contribution of the PH‐EHL to energy transfer in QLEDs is confirmed, whereas the TADF‐EHL has a significant contribution. Second, highly efficient top‐emission green QLEDs with the TADF‐EHL are achieved. They exhibit a maximum luminance (L) and current efficiency (CE) of 40700 cd m−2 and 68.0 cd A−1, respectively, which are the highest among the reported values for green‐emitting InP QLEDs. The proposed approaches are expected to provide aid in the realization of highly efficient QLEDs from the analysis to the device optimization stage.
Subject
Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials
Cited by
1 articles.
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