Effect of Size on the Luminescent Efficiency of Perovskite Nanocrystals

Abstract

Perovskite colloidal nanocrystals have emerged as important new optical materials, with tuneable light emission across the visible spectrum, narrow linewidths for high colour purity, and quantum efficiencies approaching unity. These materials can be solution processed in large volumes at low cost making them promising for optoelectronic devices. The structure of nanocrystals influences the radiative and non-radiative recombination of carriers within them through trap states and Auger recombination. To optimise the emission properties it is vital to understand the relationship between the optical emission of individual nanocrystals and their structure, size, and composition of individual nanocrystals.

Liquid-phase sintering of lead halide perovskites and metal-organic framework glasses

“…S34). The variation of CL intensity is complex in origin, highly sensitive to the crystal quality and exposure to unpassivated surface states and particle size effects ( 28 ). Despite this, the CL spectra from individual grains provided incontrovertible evidence of luminescence from glass-bound nanocrystals of γ-CsPbI 3 .…”

Water-assisted synthesis of lead-free Cu based fluorescent halide perovskite nanostructures

“…One explanation is that the luminescence is due to defects associated with the core or volume of the nanoparticle and not on the surface. 24,27 The un-shifted emission spectra of Cs2CuCl4, Cs2CuBr4, and Cs2CuBr2Cl2 perovskites can be due to d-d transition in d levels for Cu. This phenomenon has been described in the previous report, varying the halide ions in (CH3NH3)2CuCl4, (CH3NH3)2CuCl2I2, and (CH3NH3)2CuCl2Br2 perovskites the emission wavelength don't shift.…”

“…Noteworthy, the solubility of CsBr and CsCl in polar solvents (DMF and DMSO) is low than that of CuCl2 and CuBr2 precursors. 24 To overcome this solubility concern and check the long-term stability of lead-free halide perovskites, an ideal amount of water can dissolve the halide precursors in the LARP method.…”

Gradient Alloy Shell Enabling Colloidal Quantum Wells Light-Emitting Diodes with Efficiency Exceeding 22%

“…The proportion of τ 1 for the G-CQWs is much smaller than that for the control CQWs, indicating the gradient shell could effectively reduce the Auger recombination. The slow component in the nanosecond range (τ 2 ) for G-CQWs and control CQWs should be radiative charge recombination. , The τ 2 of control CQWs (1.2 ns) is much shorter than that of G-CQWs, which indicates the increased nonradiative charge recombination probability in control CQWs, such as the defect induced recombination. These results further demonstrate that the gradient shell is beneficial to reduce the exciton quenching due to Auger recombination or the defect induced nonradiative.…”