Development of lithium disilicate‐based glass‐ceramics critically depends on use of nucleating agent in the glass matrix. The present study reports the effect of externally added nucleating agent Li3PO4 in Li2O–K2O–MgO–ZnO–ZrO2–Al2O3–SiO2 system which is compared with a reference composition (GC1) (SiO2:Li2O = 2.16:1) prepared with in situ formed Li3PO4. For externally added Li3PO4, two compositions were studied. In one case (GC2) before addition of Li3PO4, SiO2:Li2O ratio in glass was maintained as 2.87:1 and in another case (GC3) SiO2:Li2O ratio in glass was maintained same as reference GC1 that is, 2.16:1. The glasses were characterized by using MAS‐NMR spectroscopy. Sintering and crystallization behavior of the glass‐ceramics was characterized by using XRD, SEM, DTA. Due to in situ formation of Li3PO4, GC1 resulted in a dense sample with finer crystals of lithium disilicate. In GC2 and GC3, externally added lithium phosphate, which was in the form of ultrafine aggregated particles, formed flower‐like colonies of radially outward crystals. Higher SiO2:Li2O ratio in GC2 resulted in lithium disilicate crystals and high viscous glass causing large air entrapment and so less densification. GC3 with higher lithia in glass showed higher densification than GC2 but only lithium metasilicate crystals were formed.

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The proposed mechanism for the degradation of dye molecules.

The modulation of electronic states of MAPbX3 perovskite nanocrystals (PNCs) (MA = CH3NH3+ and X = Br− and I−) is presented as a function of crystallite size in organic semiconductor matrix forming a type‐I heterostructure with bulk perovskites. Organic semiconductor molecule (4,4′‐bis[9‐dicarbazolyl]‐2,2′‐biphenyl [CBP] and bathocuproine [BCP]) precursors are mixed in different volumetric ratios with MAPbX3 perovskite precursors to prepare thin films. This results into an easy growth of MAPbX3 PNCs of tunable sizes from ≈110 to ≈10 nm in organic semiconductor matrix. A blue shift is observed in the photoluminescence peak (PLmax) energy over a range of ≈200 meV for MAPbI3 PNCs embedded in the BCP matrix. However, PLmax energy tunes over ≈32 meV only with a similar volumetric concentration in the case of MAPbBr3 PNCs in the same BCP matrix. Moreover, the PL blue shift is even lower in the case of CBP matrix in comparison with BCP matrix for both the perovskites. This discrepancy could be resolved by determining the resultant crystallite size using X‐ray diffraction studies and the Debye–Scherrer formula. Results about blue shift in the PL peak can be explained using the classic particle‐in‐a‐box versus excitonic Bohr radius model under a weak confinement regime.

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