Recently developed CsPbX 3 (X = Cl, Br, and I) perovskite quantum dots (QDs) hold great potential for various applications owing to their superior optical properties, such as tunable emissions, high quantum efficiency, and narrow linewidths. However, poor stability under ambient conditions and spontaneous ion exchange among QDs hinder their application, for example, as phosphors in white-light-emitting diodes (WLEDs). Here, a facile two-step synthesis procedure is reported for luminescent and color-tunable CsPbX 3 - zeolite-Y composite phosphors, where perovskite QDs are encapsulated in the porous zeolite matrix. First zeolite-Y is infused with Cs + ions by ion exchange from an aqueous solution and then forms CsPbX 3 QDs by diffusion and reaction with an organic solution of PbX 2 . The zeolite encapsulation reduces degradation and improves the stability of the QDs under strong illumination. A WLED is fabricated using the resulting microscale composites, with CommissionInternationale de I'Eclairage (CIE) color coordinates (0.38, 0.37) and achieving 114% of National Television Standards Committee (NTSC) and 85% of the ITU-R Recommendation BT.2020 (Rec.2020) coverage.

CsPbX (X = Cl, Br, I) perovskite quantum dots (QDs) have emerged as competitive candidate luminescent materials in the photoelectric fields due to their superior luminescence properties. However, the major drawback such as poor resistance to temperature, moisture, and irradiation of light, especially for the red QDs with I, hinders their practical applications. Herein, we synthesized Mn-doped CsPbCl embedded in the cage of zeolite-Y as a new orange-red phosphor for the white light-emitting diode (WLED). The composites have significantly improved resistance to both elevated temperature and water over the bare Mn-doped QDs. The former exhibits little degradation whereas the latter shows apparent decline upon the irradiation of lights in the orange LED devices, which are fabricated by employing each material as a color-conversion phosphor coated on a 365 nm UV chip. A WLED is also achieved with a 365 nm UV chip coated with a CsPb(Cl,Br)-Y blue phosphor and a CsPbMnCl-Y orange phosphor. The device possesses a Commission Internationale de l'Éclairage coordinate of (0.34, 0.36), a correlated color temperature of 5336 K and a color rendering index of 81.

Herein, a new red phosphor Na3GaF6:Mn4+ has been designed and synthesized by a facile two-step co-precipitation method at room temperature.

We present a brief review of predictions of solar cycle maximum amplitude with a lead time of 2 years or more. It is pointed out that a precise prediction of the maximum amplitude with such a lead-time is still an open question despite progress made since the 1960s. A method of prediction using statistical characteristics of solar cycles is developed: the solar cycles are divided into two groups, a high rising velocity (HRV) group and a low rising velocity (LRV) group, depending on the rising velocity in the ascending phase for a given duration of the ascending phase. The amplitude of Solar Cycle 24 can be predicted after the start of the cycle using the formula derived in this paper. Now, about 5 years before the start of the cycle, we can make a preliminary prediction of 83.2-119.4 for its maximum amplitude.

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