Synthesis and characterization of centimeter-sized CsPbBr3 perovskite single-crystals by wet chemical methods

In recent years, CsPbBr3, a stable perovskite material that does not contain organic molecules, has attracted much attention due to its excellent optical and electrical properties. However, studies on the synthesis of CsPbBr3 single-crystals are limited. Within the scope of this experimental study, it was aimed to examine the synthesis parameters of CsPbBr3 single crystal by hydrohalic solution method and antisolvent vapor crystallization method to increase the crystal size by using the nucleation method, and finally to characterize the structure of the obtained CsPbBr3 and to investigate its usability in detectors. For these purposes, CsPbBr3 single crystals were synthesized by the hydrohalic solution method and the antisolvent vapor crystallization method. In the hydrohalic solution method, a solubility graph of CsPbBr3 crystals in HBr was created. The effect of the initial ratio (Cs/Pb) in the precursor solution on the formation of different phases (Cs4PbBr6, Cs2PbBr5) was investigated. The effect of controlled temperature lowering and constant temperature conditions on the single-crystal size and morphology was observed. In the antisolvent vapor crystallization method, the initial ratio and the effect of the antisolvent on the final product were studied. In both methods, a seed crystal with uniform morphology was added to the precursor solution to increase the crystal size. As a result, it was observed that the structural properties of CsPbBr3 single crystal synthesized by the hydrohalic solution method and antisolvent vapor crystallization method were compatible with literature values. The solubility graph obtained for the hydrohalic solution method showed a linear relationship between temperature and CsPbBr3 crystal dissolution. In the nucleation method, it was observed that the single crystal seed grew in to a bigger single crystal by preserving its morphology. The seed added under controlled cooling conditions from 80 oC to 40 oC reached a size of 5 mm x 5 mm x 2 mm in just 5 days. The seed added under constant temperature conditions at 80 oC, on the other hand, reached the size of 3 mm x 3 mm x 2 mm in 10 days. In the antisolvent vapor crystallization method, it was observed that antisolvents (acetonitrile, methanol) with dielectric constants close to dimethylsulfoxide supported the formation of CsPbBr3, while antisolvents with low dielectric constant (toluene) supported the formation of Cs4PbBr6. A single crystal of CsPbBr3 with sharp boundaries was obtained in the antisolvent vapor crystallization method when the vapor pressure of methanol was reduced by mixing it with dimethylsulfoxide and a Pb/Cs ratio of 1.5. The seed placed in the precursor solution reached a size of 10 mm x 2 mm x 1 mm in just 4 days. In a relatively short time, phase pure, faceted CsPbBr3 single crystals with a size of about 10 mm and a band gap suitable for the absorption of high-energy photons have been successfully synthesized.