Preparation And Characterization Of Mn-Doped All-Inorganic Perovskite Quantum Dots

All-inorganic perovskite quantum dots?QDs?provide prominent applications in the fields of optoelectronic devices,especially low-cost light source or display,because of their remarkable properties including low cost solution preparation method,high photoluminescence quantum yields?PLQYs?,full visible spectrum of luminescence,and other excellent characteristics.But the main component,Pb is highiy toxic,which is a major hurdler for the practical manufacturing.Mn-doped all-inorganic perovskite QDs with reduced lead content has excellent optical properties of dual-color emission.However,the existing synthesis approaches of hot injection usually require hash conditions,such as high temperature and nitrogen protection.In this thesis.We design a gram-scale approach to synthesize CsPbxMn1-xCl QDs and CsPbxMn1-xBryCl3-y QDs.The Mn-doped all-inorganic perovskite QDs are synthesized in gram-scale at the low temperature in the air.The main contents of the paper are as follows.?1?We use Pb?CH₃COO?₂ instead of PbCl₂ as Pb precursor.The effects of different synthesis temperatures,different Cs²⁺precursors,and different MnCl₂ and Pb?CH₃COO?₂feed ratios on the morphology,luminescence,and PLQYs of quantum dots have been investigated.The as-prepared CsPb_xMn_1-xCl₃ QDs have dual-color emission,the weaker emission peak around at 400nm,and the Mn-related emission peak around 600nm.The quality of Mn-doped all inorganic QDs prepared by the cesium acetate are better than the cesium carbonate.The best reaction temperature for gram-scale synthesis of Mn-doped all inorganic QDs is 100°C,and the best MnCl₂ and Pb?CH₃COO?₂ feed ratio is 7:3.The crystalline phase of the CsPb_x Mn_1-xCl₃ quantum dots synthesized by different feed ratios are consistent with tetragonal CsPbCl₃.?2?We study the influence of MnCl₂ and PbBr₂ feed ratio on the synthesis of CsPb_xMn_1-xBr_yCl_3-y QDs.The as-prepared CsPb_1-xMn_x Cl_yBr_3-y QDs exhibit dual-color emission with two strong emission peaks around at 400-450 nm and 600 nm.Whereas,the emission peak around at 400nm shows consistently enhanced intensity with decreased Mn-to-Pb feed ratio.However,the position of the wavelength around at 400nm has a shift with change of halogen.?3?The CsPb_x Mn_1-xCl₃ QDs has been demonstrated as invisible ink for encryption applications.We mix the CsPb_xMn_1-xBr_yCl_3-y QDs with PDMS for producing polymer composites.