Environmentally friendly quantum-dot color filters for ultra-high-definition liquid crystal displays

Abstract

This work reports the synthesis and application of highly tuned cadmium-free green and red InPZnSe1−xSx/ZnS quantum dots (QDs) in QD enhanced liquid crystal displays (LCD). The emissions of the quantum dots were synthetically tuned to sharp emissions at low full-width at half maximum. The QDs were incorporated in LCD devices as quantum dot enhancement film (QDEF) or as a quantum dot incorporated color filter (QDCF). Synthetic tuning of the gradient inter-shell in the QDs leads to reduced full width at half-maximum, resulting in sharp green and red emissions from both types of devices. The application of the same QDs to devices using these different integration techniques shows the superiority of QDCF devices over QDEF ones. The RGB color gamut of a QDCF-LCD was 81.4% of REC.2020 in the CIE 1931 color space compared to 71.2% obtained for a QDEF-LCD display. The improved performance of QDCF was mainly due to the optimal interactions between the green QDs and the green color filter. The superior performance of cadmium-free InPZnSe1−xSx/ZnS QDCFs in LCDs make them well-suited for ultra-high-definition TV formats.

Are substitutes to Cd-based quantum dots in displays more sustainable, effective, and cost competitive? An alternatives assessment approach

“…3B). Touted as more sustainable than Cd-QDs in industry, 64 In-QDs do not score as less hazardous in this assessment. Although In-QDs do score better than Cd-QDs in their environmental safety by 1 point, In-QDs score an average of 0.3 and 0.1 worse in health and physical properties, respectively, than Cd-QDs.…”

“…This was surprising to us given the excitement in the literature regarding the sustainability of perovskites 55 and In-QDs. 64 However, this alternatives assessment was not meant to conclusively rank all different substance classes or substances in this field, but rather to illustrate a method that could be used to assess new materials. This method has gaps in each assessment that can be filled by other researchers.…”

Prospects and challenges of mini‐LED, OLED, and micro‐LED displays

“…Recently, they have increased the color coverage of InP-based QDEF LCD panels to 71.2% Rec.2020 in the CIE 1931 color space. 132 Compared with the cadmium-based QDEF that can cover more than 80% Rec.2020 in the 1931 color space, there is still room for improvement.…”

Development of Quantum Dot (QD) Based Color Converters for Multicolor Display

“…They have been used as color conversion layers in liquid crystal displays (LCDs) as well as in LED (including OLED) displays because of their color purity (narrow emission) and high luminescence efficiency [ 7 , 10 , 11 , 12 ]. In LCDs, they have been extensively explored as QD-enhancement films (QDEFs) [ 7 , 10 , 13 , 14 , 15 ] where a mixture of green and red QDs on top of a blue backlight is used to partially convert the blue light into green and red color at the back of the display. This mixture of white light is then used to generate perfectly blue, green and red color using color filters at the front of the displays.…”