One-step synthesis of all-inorganic high-entropy dual-phase Cs‘B’Br3/Cs‘B’2Br5 perovskite nanocrystals by high-energy ball milling

All-inorganic lead halide perovskite nanocrystals (NCs) have attracted considerable attention in field of optoelectronics due to their excellent properties such as high PLQY , tunable emission spectra in visible light region, and narrow emission peaks. However, problems existing in the research of all-inorganic lead halide perovskite materials are high lead content, low stability, and complex synthesis processes. Those problems need to be solved urgently. Therefore, dual-phase Cs‘B’Br 3 /Cs‘B’ 2 Br 5 perovskite material (Cs(Pb 1/5 Mn 1/5 Ni 1/5 Zn 1/5 Cd 1/5 )Br 3 /Cs(Pb 1/5 Mn 1/5 Ni 1/5 Zn 1/5 Cd 1/5 ) 2 Br 5 ) was synthesized by doping the B-site of CsPbBr 3 and CsPb 2 Br 5 using high-energy ball milling in this thesis. This dual-phase perovskite material has maximum absorption edge of 540 nm, a band gap width of 2.22 eV, the maximum emission peak at 600 nm with FWHM of 72 nm, PLQY of 24.50%, and an average fluorescence lifetime of 227.87 μs. After 21 days at room temperature, luminescent intensity of NCs increased to 156%, and still retained 109% at 120 days. After treatment at 150 °C, luminescent intensity decreased to 47%. Results show that this high-entropy dual-phase perovskite has great stability in different temperature. This proves that synthesis of high-entropy dual-phase halide perovskite by high-energy ball milling is feasible, and has great significance in solving poor stability and high lead content of all-inorganic lead halide perovskite in the future.