Search

Perovskite quantum dots (PeQDs) are seen as the credible alternative to traditional QDs ascolor converter in liquid crystal display (LCD). Unfortunately, PeQDs sufferfrom instability and color separation, and the prepared PeQDs enhanced films(PQDFs) need the protection of expensive barrier layers, which significantly increases price and limits their application. Herein, large‐area yellow monolithic PQDF is fabricated with both green CsPbBr3 and red CsPbBr1I2QDs encapsulated in the dual matrices of inorganic glass and polypropylene (PP) via an industrialized melt extruding & rolling method. The PQDF shows high photoluminescence quantum yield (PLQY) of 92% and narrow full width at half maximum (FWHM) of 19 nm (green) and 33 nm (red). Importantly, the bare PQDF without barrier layers can pass harsh aging test at 85 °C/85% RH and reach anoperating T90 lifetime over 1000 h. Finally, a white backlit unit is designed by coupling yellow monolithic PQDF with blue light guide panel, and the constructed prototype display shows superior color rendering performance forits narrow green/red emissions, reaching a color gamut of 110% National Television System Committee (NTSC). This work provides a novel and easy‐to‐industrialize route to prepare PQDFs to realize their commercial application in backlit display. [ABSTRACT FROM AUTHOR]

Robust amorphous glass protected CsPbBr3 (CsPbBr3@glass) perovskite quantum dots (PeQDs) with ultra‐pure green emission and superior long‐term stability are highly desirable for developing wide‐color‐gamut liquid crystal displays. However, most of the reported CsPbBr3@glass nanocomposites are subject to low external quantum efficiency (EQE). This work demonstrates that ZrO2 additive has an "accumulation" effect on the borosilicate glass network structure to promote in situ nucleation/growth of PeQDs inside glass rather than self‐crystallization. This effect is beneficial in reducing surface defects, improving the quality of PeQDs, and thus boosting radiative recombination of excitons. As a consequence, the as‐prepared CsPbBr3@glass shows a record EQE of up to 75% and can pass the accelerated aging tests at 85 °C/85% RH for 1000 h and blue light irradiation over 2000 h. Finally, a prototype display using CsPbBr3@glass‐based straight‐down backlit unit is designed and gains more favorable responses in blind selection tests for its high brightness of 2647 cd m−2 and high color purity of 88%. The findings will pave the way for realizing the commercial application of CsPbBr3@glass nanocomposite in PeQDs‐converted backlit display. [ABSTRACT FROM AUTHOR]

The complex and high‐precision patterning of perovskite quantum dots (PeQDs) is of vital importance for exploring their new functionalities and device applications. In this work, a strategy based on the combination femtosecond (fs) laser‐irradiation and humidity‐control is reported to construct patterns of cyan CsPb(Cl/Br)3 PeQDs in a transparent glass medium. Benefiting from their ionic crystal feature and low formation energy, CsPb(Cl/Br)3 PeQDs can be locally crystallized and decomposed via fs laser irradiation without further heat‐treatment. More notably, it is found that a water molecule is able to affect the growth of CsPb(Cl/Br)3 PeQDs in glass. By modulation of relative humidity in air, the selectively decomposed perovskite structure is spontaneously regenerated, and the highly emissive CsPb(Cl/Br)3 PeQDs can be in situ manufactured in the confined glass region. This allows for reversible luminescence from the same patterns of laser printing‐erasing‐recovering, and the process can be repeated for multiple cycles without destruction of optical performance and robustness. The results provide a flexible method to develop new encryption/decryption technology for information security and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

High‐quality backlit display puts forward urgent demand for color‐converting materials. Recently, metal halide perovskites (MHPs) with full spectral tunability, high photoluminescence quantum yields (PLQYs), and high color purity have found potential application in wide‐color‐gamut display. Regrettably, naked MHPs suffer from long‐term instable issue and cannot pass harsh stability tests. Herein, amorphous‐glass‐protected green/red CsPbX3 quantum dots (QDs) are prepared by elaborately optimizing glass structure, perovskite concentration, and in situ crystallization. PLQYs of green CsPbBr3@glass and red CsPbBr1.5I1.5@glass reach 94% and 78%, respectively, which are the highest ones of CsPbX3@glass composites reported so far and comparable to colloidal counterparts. Benefited from complete isolation of QDs from external environment by glass network, CsPbX3@glass can endure harsh commercial standard aging tests of 85 °C/85%RH and blue‐light‐irradiation, which are applied to construct white light‐emitting diodes (wLEDs) with high external quantum efficiency of 13.8% and ultra‐high luminance of 500 000 cd m−2. Accordingly, the perovskite wLED arrays‐based backlit unit and a prototype display device are designed for the first time, showing more vivid and wide‐color‐gamut feature benefited from narrowband emissions of CsPbX3 QDs. This work highlights practical application of CsPbX3@glass composite as an efficient and stable light color converter in backlit display. [ABSTRACT FROM AUTHOR]

Laser‐driven projection display puts forward urgent demand for color converter materials to achieve wide‐color‐gamut and high‐quality image presentation. In this study, a hierarchical structure quantum dots‐in‐glass film (QiGF) is fabricated via co‐sintering stable green/red‐emitting CsPbX3@glass (X3 = Br3, Br1.5I1.5) and commercial low‐melting glass on the sapphire substrate. Benefiting from the well‐retained optical properties of CsPbX3 quantum dots in amorphous glass and high thermal conductivity, QiGF succeeded in inhibiting luminescence saturation after 20 W mm−2 blue laser irradiation. A brand‐new white‐lighting source designed by coupling a blue laser with a pattern "QiGF wheel" produced ultra‐narrow blue/green/red tri‐color emissions and total luminous flux of 146 lm. Accordingly, a QiGF‐converted laser projection system is successfully designed for the first time, showing more natural and real color restoration for its wide color gamut display feature (157% of conventional light‐emitting diode projection and 107% of NTSC standard). The present study highlights the practical application of CsPbX3 quantum dots composite as an efficient laser‐driven color converter in projection display. [ABSTRACT FROM AUTHOR]

Halogen‐mixed CsPb(Br/I)3 perovskite quantum dots (PeQDs) embedded glass can address the issue of stability, but suffers from low photoluminescence quantum yields (PLQYs) for the hindered in situ nucleation/growth inside the robust glass network. Uncovering the exact mechanism is highly desirable to develop high‐performance CsPb(Br/I)3@glass for commercial applications, but the topic remains unexplored. Here, based on femtosecond transient (fs‐TA) absorption, temperature‐dependent PL spectra, and theoretical calculations, a comprehensive understanding on heat‐treatment (HT) temperature‐induced modification of microstructures and carrier dynamics in the CsPb(Br/I)3@glass is build. It is evidenced that high‐temperature HT will promote more I− ions diffusion from glass matrix into CsPb(Br/I)3 lattice, leading to the retarded hot carrier (HC) cooling, and improved exciton recombination. This is attributed to the synergistic effect of the reduced effect carrier mass, the weakened carrier‐phonon coupling, the inhibited Klemens channel, and the eliminated defect states. Revealing these underlying mechanisms will empower to exert precise control and optimize PLQY of CsPb(Br/I)3@glass up to near unity. [ABSTRACT FROM AUTHOR]

Elaborate engineering of emitting wavelength of green down‐converter in the spectral range of ≈525–535 nm with narrow full‐width at half‐maximum (fwhm < 25 nm) is an essential prerequisite for faithfully reproducing colors in the quantum dot (QD)‐based backlit display. Herein, different from the previous complex synthesis for green films, FAPbBr3 perovskite QDs films are fabricated by a dual‐additive assisted in situ growth strategy. Both C6H5CH2CH2NH3+ and 1,4,7,10,13,16‐hexaoxacyclooctadecane additives are introduced to synergistically tune green emitting (≈525–535 nm) with the narrowest fwhm down to 21 nm and the highest photoluminescence quantum yield (PLQY) up to 99%. Improved nanocomposite film with excellent long‐term stability is used to construct a prototype liquid crystal display (LCD) with a wide color gamut (118% National Television System Committee and 88% Recommendation BT 2020), a high saturation, and a remarkable color rendition. The performance is superior to that of the commercial white‐LED‐based LCD, showing a great potential of the present green film for high‐definition display application in the future. [ABSTRACT FROM AUTHOR]