Here, we survey the synthesis method for colloidal lead halide perovskite nanocrystals (APbX3, NCs, A=Cs+, FA+, FA=formamidinium; X=Cl, Br, I) and prospects of these NCs for optoelectronic applications such as in television displays, light-emitting devices, and solar cells, emphasizing the practical hurdles that remain to be overcome. The sponaneous and stimulated emission spectra of these NCs are readily tunable over the entire visible spectral region of 410-700 nm. The photoluminescence of these NCs is characterized by narrow emission line-widths of 12-42 nm, wide color gamut covering up to 140% of the NTSC color standard, high quantum yields of up to 100%. Cs1-xFAxPbI3 and FAPbI3 reach the near-infrared wavelengths of 800 nm. Their processing and optoelectronic applications are, however, hampered by the loss of colloidal stability and structural integrity due to the facile desorption of surface capping molecules during isolation and purification. To address this issue, we have developed a new ligand capping strategy utilizing common and inexpensive long-chain zwitterionic molecules such as 3-(N,N-dimethyloctadecylammonio) propanesulfonate, resulting in much improved chemical durability. In particular, this class of ligands allows for the isolation of clean NCs with high photoluminescence quantum yields of above 90% after 4 rounds of precipitation/redispersion along with much higher overall reaction yields of uniform and colloidal dispersible NCs. Densely packed films of these NCs exhibit high photoconductivity, high photoluminescence quantum yields and and low thresholds for amplified spontaneous emission. Perovskite NCs also readily form long-range ordered asssemblies known as superlattices. These assemblies exhibit accelerated coherent emission (superfluorescence), not observed before in semiconductor nanocrystal superlattices.

Colloidal nanocrystals of APbX3 perovskites [A=Cs+, CH(NH2)2+, X=Cl-, Br-, I-]: Surface chemistry, self-assembly and potential applications

256th National Meeting (2018)

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