Tuning the Luminescence Properties of Organometal Halide Perovskites for Light-Emitting Applications

Organometal halide perovskites are inexpensive materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology, but suffering from the low photoluminescence quantum yields at low excitation fluencies.² We developed a ligand-assisted reprecipitation (LARP) strategy to fabricate CH₃NH₃PbX₃ (X=Br, I, Cl) nanocrystals.³ By controlling their size and shape, we demonstrated the size- and shape- dependent photoluminescence properties. Especially, we obtain brightly-luminescent and color-tunable colloidal quantum dots with absolute quantum yield up to 70% at room temperature and low excitation fluencies. The comparisons between small sized CH₃NH₃PbBr₃ quantum dots (average diameter 3.3 nm) and corresponding micrometer-sized bulk particles (2-8 μm) suggest that the intense increased photoluminescence quantum yield originates from the increase of exciton binding energy due to size reduction as well as proper chemical passivations of the Br rich surface. We further demonstrated the fabrication of prototype light-emitting devices, providing enhanced color quality for display technology.

[1] Shirasaki, Y.; Supran, G. J.; Bawendi, M. G.; Bulovic, V. Nat. Photon. 2013, 7, 13-23

[2] Stranks, S. D.; Burlakov, V. M.; Leijtens, T.; Ball, J. M.; Goriely, A.; Snaith, H. J. Phys. Rev. Appl. 2014, 2, 034007.

[3] Zhang, F.; Zhong, H. Z.; Chen, C.; Wu, X. G.; Hu, X. M.; Huang, H. L.; Han, J. B.; Zou, B. S.; Dong, Y. P. ACS Nano 2015, DOI: 10.1021/acsnano.5b01154