Super Ultra-High Resolution Liquid-Crystal-Display Using Perovskite Quantum-Dot Functional Color-Filters

Abstract

Quantum dot enhancement film (QDEF) working in tandem with a blue light-emitting-diode (LED) back-light-unit (BLU) has been recently used in liquid crystal display (LCD) to minimize the cross talks between the polarized emitting B-, G-, and R-light. However, they still exhibit a fundamental and considerable emitting-light-power loss from QDEF because of the light absorption loss in resin and transparent films of QDEF. In this work, we propose and demonstrate the superiority of the LCD using blue-(B-), green-(G-), and red-(R-) perovskite-quantum-dot (PrQD) functional CFs coupled with a blue LED BLU. This LCD using PrQD functional CFs and a blue LED BLU features cross-talk free spectra of polarized emitting B-, G-, and R-light, maximizing the LCD color gamut and exhibiting a world record performance of over 102.7% (137%) of Rec.2020 standard (NTSC standard). Theoretically, such an improvement in color gamut would facilitate unlimited scaling-down of the pixel leading to super ultra-high resolution LCD.

Light Generation in Lead Halide Perovskite Nanocrystals: LEDs, Color Converters, Lasers, and Other Applications

“…The significant progress that has been made for LHP‐NC‐based LEDs in terms of luminous efficiency has been offset by their unsatisfactory operational stability, leaving the potential of this cutting‐edge display technology uncertain. In principle, without directional ion migration driven by an applied electric field, LHP‐NCs that work as color converter under only optical excitation are significantly more stable, and all of the considerations concerning electrical features, e.g., charge carrier transport and injection, and related technical questions, e.g., film morphology and compatibility, can be neglected ( Table 2 ). Moreover, quasi‐2D LHP NCs, and especially the lead‐free halide double perovskite NCs that are difficult to use in LEDs, can be used appropriately in various applications under optical excitation.…”

“…Moreover, quasi‐2D LHP NCs, and especially the lead‐free halide double perovskite NCs that are difficult to use in LEDs, can be used appropriately in various applications under optical excitation. Similar to consumer TVs using CdSe quantum dots color converters, LHP‐NCs can also be adopted to serve as superb color converters in full color displays in virtue of their high color purity, wide color gamut coverage, near‐unity PLQY, and low cost (Figure c) . Utilizing the color filters integrated with red, green, and blue CsPbX 3 QDs, a liquid crystal display can exhibit an unprecedented color gamut over the NTSC standard under illumination by blue LEDs …”

“…Light emission from lead halide perovskites (LHPs) was reported over a decade ago; however, weak emissions at room temperature hindered the application of LHPs in light‐emitting devices because LHPs did not show any electroluminescence at the time . In the past few years, LHPs have returned to the spotlight in the form of nanoscale emitters because of their superior features in light generation and resulting applications . Low‐cost solution processing techniques are used to fabricate LHP nanocrystals (LHP‐NCs), and impressive achievements have been made in using LHP‐NCs in high‐brightness light‐emitting diodes (LEDs) with high external quantum efficiency (EQE) and as color converters for lighting and full‐color displays that have a wide color gamut and near‐unity luminous efficiency .…”

“…As the most attractive application, red and green LEDs exhibit much higher performances with EQEs >20% and high brightness that are comparable to organic LEDs and CdSe quantum dot LEDs; however, blue LEDs still have an EQE of ≈5.7% and a maximum brightness of 3780 cd m −2 . LHP‐NCs have narrow band emissions and are therefore not the best color convertors for white LEDs in lighting; however, low‐cost phosphors exhibit similar performance to lanthanide based white LEDs . In addition to applications based on efficient luminescence under low excitation density, LHP‐NCs exhibit optically pumped low‐threshold lasing and proof‐of‐principle electrically excited lasing .…”

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

“…We had recently demonstrated a new approach to enhancing the LCD display with perovskite QDs. Blue, green and red inorganic perovskite QDs were incorporated into the color filter element in the LCD to form a functional quantum dot incorporated color filter (QDCF)-to achieve lower overlap between RGB color elements in pixels 8 . Lead halide perovskites has high-intensity emissions with narrow full width at half-maximum (FWHM) 13 .…”