Aspiration-assisted fabrication of patterned quantum dot films for photo-emissive color conversion
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Aspiration-assisted fabrication of patterned quantum dot films for photo-emissive color conversion Yalian Weng1, Xiaocong Lai1, Guixiong Chen1, Xiongtu Zhou1,2,* , Qun Yan1,2, Chaoxing Wu1,2, Tailiang Guo1,2, Jie Sun1,2, and Yongai Zhang1,2,* 1 2
College of Physics and Information Engineering, Fuzhou University, Fuzhou 350116, Fujian, People’s Republic of China Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350116, Fujian, People’s Republic of China
Received: 26 July 2020
ABSTRACT
Accepted: 19 September 2020
The fabrication of patterned quantum dot (QD) films is of great importance for color displays based on photo-emissive color conversion. In this work, a novel and precise alignment-free fabrication method of patterned quantum dot color conversion (QDCC) films was proposed by introducing into aspiration-assisted lithography. QDs dispersed in mixed polymer/toluene solvent can be imbibed via predetermined micro-channels with the assist of aspiration. The results show that uniform QDCC films with multicolor QDs could be achieved by adjusting the polymer/toluene ratios and the aspiration time. Superfine QD patterns with a width of around 8 lm could also be obtained by varying the interfacial free energies of substrates. A color conversion device using a turquoise OLED and the QDCC films incorporated with distributed Bragg reflector have been demonstrated, exhibiting a conversion efficiency up to 23.27%.
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
Introduction In comparison with liquid crystal displays (LCDs), emissive displays such as organic light emitting diodes (OLEDs) and light emitting diodes (LEDs) possess great natural advantages in key issues like deep black level (high contrast ratio), high response speed and high brightness [1–4]. To realize three primary-color emissive displays, three methods can be usually adopted. The first is to initially produce a
white light source and then separate its component colors at each pixel using color filter (CF); this CFbased route often suffers from severe loss of light efficiency and low color gamut [4, 5]. The second is to create individually addressable light with excitation wavelengths of red (R), green (G) and blue (B), this RGB light emitting route has much higher light efficiency, and however, it requires precise alignment for each pixel and complicated driving circuit to maintain the color rendering index (CRI) during operation [6, 7]. In particular, it becomes technical challenging
Handling Editor: Pedro Camargo.
Address correspondence to E-mail: [email protected]; [email protected]
https://doi.org/10.1007/s10853-020-05369-w
J Mater Sci
when the pixels scale down [8]. The last but not least is the photo-emissive color conversion method, in which short-wavelength light emitting matrixes (e.g., blue light matrixes) are used; then, the green and red light is down converted by color conversion layer after absorbing the blue light [9–12]. This approach has many benefits
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