Dual-Protective CsPbX₃ Perovskite Nanocomposites with Improved Stability for Upconverted Lasing and Backlight Displays

Abstract

Recently, perovskite nanocrystals (NCs) have been recognized as a substitute for the conventional phosphor color converters, which can improve the color gamut and reproduction of liquid crystal displays (LCDs). However, the issue of instability has always been a stumbling block to practical applications. Here, a novel dual-phase mixed@glass@styrene−ethylene−butylene−styrene (SEBS) (MGS) nanocomposite is synthesized by three simple steps and the optimal photoluminescence quantum yield (PLQY) is 50%. Benefiting from the dual protection of the glass matrix and SEBS film re-encapsulation, the MGS composite shows typical bright green emission, significant improvement in water/ thermal/photon resistance, and environmental friendliness. Moreover, combining the as-prepared red emitter and the green-emitting MGS film with a blue InGaN chip as the backlight, an efficient white light-emitting diode (wLED) for backlights is fabricated. The gamut of the prepared LCD covers 131 and 97.7% National Television System Committee (NTSC) 1953 and Rec. 2020, respectively. In addition, random upconverted laser emission is achieved by low-power two-photon pumping. Hence, the dual-protective composite material with exceptional stability provides a feasible path for backlight display and upconverted lasing.

Synthesizing Bright CsPbBr3 Perovskite Nanocrystals with High Purification Yields and Their Composites with In Situ-Polymerized Styrene for Light-Emitting Diode Applications

“…Since their debut in 2014, lead halide perovskite nanocrystals (PNCs) with a formula of APbX 3 (A = Cs + , HC­(NH 2 ) 2 + , CH 3 NH 3 + ; X = Cl – , Br – , or I – ) have received considerable attention. − This is due to the fact that they possess outstanding photophysical properties, such as large absorption cross section, short radiative lifetimes, high photoluminescence (PL) quantum yields (PLQYs), and tunable PL. , Together with facile solution-phase synthesis under ambient conditions, these excellent features make PNCs promising luminescent materials for diverse optoelectronic applications, such as light-emitting diodes (LEDs), − lasers, photodetectors, liquid-crystal display (LCD) backlights, etc . Up to now, significant progress in device performance has been made.…”

Space-confined growth of large-mismatch CsPb(BrxCI1−x)3/GaN heterostructures with tunable band alignments and optical properties

“…The similar phenomenon about the ambient stability of CsPbX 3 (X = Cl, Br) has also been reported in the literature. 44,45…”

“…The similar phenomenon about the ambient stability of CsPbX 3 (X = Cl, Br) has also been reported in the literature. 44,45 In order to further confirm that the CsPb(Br x Cl 1−x ) 3 samples with high Cl composition have higher ambient stability, we have made a stability comparison between the asgrown CsPbBr 3 and CsPbCl 3 on the GaN substrate. Here the perovskite samples were exposed to air and etched under hightemperature conditions (300 °C).…”

Intragap State Engineering for Tunable Single-Photon Upconversion Photoluminescence of Lead Halide Perovskite

“…Lead halide perovskites have shown immense potential in photovoltaic and photoelectronic areas owing to their compelling photophysical properties, such as large absorption cross-section, long charge carrier diffusion length, and superior defect tolerance . Specifically, their composition-tunable bandgap and high photoluminescence quantum yield (PLQY) make them promising as the active medium for light-emitting diode, lasing, and displays . In recent years, remarkable single-photon upconversion photoluminescence (SPUC-PL) from perovskites has been reported, which, combined with the intrinsically small Stokes shift, is responsible for their high-efficiency photon recycling , and laser cooling. , Unlike the traditional multiphoton upconversion mediated by a virtual state, the intermediate state of the SPUC-PL is “actual”, whereby the upconversion takes place in a phonon-assisted manner. , As a result, the SPUC-PL usually possesses a much larger light absorption cross-section than the multiphoton one, which brings about versatile applications of the SPUC-PL including but not limited to background-free fluorescence microscopy imaging, broadband sunlight conversion, optical refrigeration, and infrared (IR) photodetection .…”

“…3 Specifically, their compositiontunable bandgap 4 and high photoluminescence quantum yield (PLQY) 5 make them promising as the active medium for lightemitting diode, lasing, and displays. 6 In recent years, remarkable single-photon upconversion photoluminescence (SPUC-PL) from perovskites has been reported, which, combined with the intrinsically small Stokes shift, is responsible for their high-efficiency photon recycling 7,8 and laser cooling. 9,10 Unlike the traditional multiphoton upconversion mediated by a virtual state, the intermediate state of the SPUC-PL is "actual", whereby the upconversion takes place in a phonon-assisted manner.…”