Photophysical properties of wavelength-tunable methylammonium lead halide perovskite nanocrystals

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2016-11, Vol.5 (1)
• Main Authors: Freppon, Daniel J., Men, Long, Burkhow, Sadie J., Petrich, Jacob W., Vela, Javier, Smith, Emily A.
• Format: Article
• Language: English
• Subjects: 30 DIRECT ENERGY CONVERSION; MATERIALS SCIENCE
• ISSN: 2050-7526; 2050-7534

Here we present the time-correlated luminescence of isolated nanocrystals of five methylammonium lead mixed-halide perovskite compositions (CH3NH3PbBr3$-$xIx) that were synthesized with varying iodide and bromide anion loading. All analyzed nanocrystals had a spherical morphology with diameters in the range of 2 to 32 nm. The luminescence maxima of CH3NH3PbBr3$-$xIx nanocrystals were tuned to wavelengths ranging between 498 and 740 nm by varying the halide loading. Both CH3NH3PbI3 and CH3NH3PbBr3 nanocrystals exhibited no luminescence intermittency for more than 90% of the 250 s analysis time, as defined by a luminescence intensity three standard deviations above the background. The mixed halide CH3NH3PbBr0.75I0.25, CH3NH3PbBr0.50I0.50, and CH3NH3PbBr0.25I0.75 nanocrystals exhibited luminescence intermittency in 18%, 4% and 26% of the nanocrystals, respectively. Irrespective of luminescence intermittency, luminescence intensities were classified for each nanocrystal as: (a) constant, (b) multimodal, (c) photobrightening, and (d) photobleaching. Finally, based on their photophysics, the CH3NH3PbBr3$-$xIx nanocrystals can be expected to be useful in a wide-range of applications where low and non-intermittent luminescence is desirable, for example as imaging probes and in films for energy conversion devices.