scholarly journals Improvement in Luminous Efficacy and Thermal Performance Using Quantum Dots Spherical Shell for White Light Emitting Diodes

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 618 ◽  
Author(s):  
Songmao Chen ◽  
Caiman Yan ◽  
Yong Tang ◽  
Jiasheng Li ◽  
Xinrui Ding ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Spherical Shell ◽  
Thermal Performance ◽  
White Light ◽  
Shell Structure ◽  
Light Emitting Diodes ◽  
Planar Structure ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
White Light Emitting Diodes

White light-emitting diodes (WLEDs) based on quantum dots (QDs) are gaining increasing attention due to their excellent color quality. QDs films with planar structure are universally applied in WLEDs for color conversion, while they still face great challenges in high light extraction and thermal stability. In this study, a QDs film with a spherical shell structure was proposed to improve the optical and thermal performance for WLEDs. Compared with the conventional planar structure, the luminous efficacy of the QDs spherical shell structure is improved by 12.9% due to the reduced total reflection effect, and the angular-dependent correlated color temperature deviation is decreased from 2642 to 283 K. Moreover, the highest temperature of the WLED using a QDs spherical shell is 4.8 °C lower than that of the conventional WLED with a planar structure, which is mainly attributed to larger heat dissipation area and separated heat source. Consequently, this QDs spherical shell structure demonstrates superior performance of QDs films for WLEDs applications.

53% Efficient Red Emissive Carbon Quantum Dots for High Color Rendering and Stable Warm White‐Light‐Emitting Diodes

2017 ◽  
Vol 29 (37) ◽  
pp. 1702910 ◽  
Author(s):  
Zifei Wang ◽  
Fanglong Yuan ◽  
Xiaohong Li ◽  
Yunchao Li ◽  
Haizheng Zhong ◽  
...  
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Light Emitting Diodes ◽  
Carbon Quantum Dots ◽  
Light Emitting ◽  
Warm White Light ◽  
White Light Emitting Diodes ◽  
Color Rendering

scholarly journals Solvent regulation synthesis of single-component white emission carbon quantum dots for white light-emitting diodes

2021 ◽  
Vol 10 (1) ◽  
pp. 465-477
Author(s):  
Longshi Rao ◽  
Qing Zhang ◽  
Mingfu Wen ◽  
Zhongfa Mao ◽  
Huaxian Wei ◽  
...  
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Light Emitting Diodes ◽  
Carbon Quantum Dots ◽  
Single Component ◽  
Great Promise ◽  
Solvent Engineering ◽  
Light Emitting ◽  
White Emission ◽  
White Light Emitting Diodes

Abstract White light-emitting diodes (WLEDs) hold great promise in lighting, display, and visible light communication devices, and single-component white emission carbon quantum dots (SCWE-CQDs) as the key component of WLEDs have many outstanding advantages. However, rapid and efficient synthesis of SCWE-CQDs with high photoluminescence quantum yield (PLQY) and stability remains challenging. Here, we report a novel solvent engineering strategy to obtain highly photoluminescent SCWE-CQDs by controlling the dilution ratios between N,N-dimethylformamide (DMF) and pristine red carbon quantum dots (RCQDs) solution. By optimizing synthesis conditions, the relative PLQY of the SCWE-CQDs solution reached 53%. Morphological, structural, and optical property characterizations indicate that the combined action of the hydrogen bond (HB) effect and the size effect leads to the blue shift of RCQDs, but the HB effect is more dominant than the particle size in causing large spectral shifts. In addition, the WLEDs with high color rendering index of 89 and remarkable reliability were obtained based on the highly photoluminescent SCWE-CQDs. This facile solvent engineering approach for synthesizing tunable emission CQDs will promote the progress of carbon-based luminescent materials for applications in optoelectronic devices.

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