Abstract
Quantum dots (QDs) as emerging light-converting materials show the advantage of enhancing color quality of white light-emitting diode (WLED). However, WLEDs employing narrow-emitting monochromic QDs usually present unsatisfactory color rendering in the orange region. Herein, composite orange-red QDs (composite-QDs) are developed through mixing CdSe/ZnS-based orange QDs (O-QDs) and red QDs (R-QDs) to compensate the orange-red light for WLEDs. We investigated the effect of self-absorption and fluorescence resonance energy transfer (FRET) process in composite-QDs on the spectral controllability and fluorescent quenching in WLEDs. The concentration and donor/acceptor ratios were also taken into account to analyze the FRET efficiency and help identify suitable composite-QDs for color compensation in the orange-red light region. As the result, the optimized composite-QDs effectively improve the color rendering index of the WLED compared with monochromatic QDs.
Highlights
Light-emitting diodes (LEDs) have attracted significant research interests in solid-state lighting applications due to their high efficiency, long lifetime, low-power consumption, fast response time, and high reliability [1–6]
Our study reveals that the concentration of the composite-quantum dots (QDs) and the proportion of donor-QDs and receptor-QDs play an important role in the energy transfer efficiency and spectrum stability
The self-absorption has a significant influence on the fluorescence resonance energy transfer (FRET) between different monochromic QDs in the composite-QDs
Summary
Light-emitting diodes (LEDs) have attracted significant research interests in solid-state lighting applications due to their high efficiency, long lifetime, low-power consumption, fast response time, and high reliability [1–6]. WLEDs are usually fabricated by packaging yellow-, green-, and red-emitting phosphors with blue-LED chips [7–9]. The full-spectrum WLEDs employ composite phosphors with a high proportion of red phosphor [10]. Classical red phosphors have a broad emission that causes lumen loss in the red-light-emitting region because the human eye is insensitive to the wavelength longer than 650 nm [11]. Quantum dots (QDs) have been employed to fabricate high-quality WLEDs. Compared to classical phosphors, QDs have unique optical properties, such as sizedependent wavelength tunability, high photoluminescence
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