Fig. 6: CNC-size-dependent asymmetric PL spectra. | Communications Physics

Fig. 6: CNC-size-dependent asymmetric PL spectra.

From: Semi-empirical approach to assess externally-induced photoluminescence linewidth broadening of halide perovskite nanocrystals with particle-size distribution

Fig. 6

a Schematic representation of the asymmetric PL-\(\lambda\) spectrum \(f\)(λ) and the corresponding PL-\(\omega\) spectrum f\((\omega )\) which arise solely from the asymmetric CNC-size distribution \(g(R)\) for \({D}_{{{{{{\rm{p}}}}}}} < 3.0\ {{{{{\rm{nm}}}}}}\,\left(={R}_{{{{{{\rm{p}}}}}}} < 1.5\ {{{{{\rm{nm}}}}}}\right).\) In this small-\(R\) region, all three FWHMs \({\varGamma }_{{{{{{\rm{SD}}}}}}}\left(R\right),{\varGamma }_{{{{{{\rm{SD}}}}}}}\)(λ)\(,\) and \({\varGamma }_{{{{{{\rm{SD}}}}}}}(\omega )\) are exclusively caused by the CNC-size distribution because \({\varGamma }_{{{{{{\rm{LO}}}}}}}\left(\lambda \right)=0\) and \({\varGamma }_{{{{{{\rm{SD}}}}}}}(\lambda )\gg {\Gamma }_{{{{{{\rm{QC}}}}}}}(\lambda )\) for \({D}_{p} < 3.2\ {{{{{\rm{nm}}}}}}.\) b Size-distribution function \(g\left(R\right)\) and the corresponding \(f(\lambda )\) spectrum with a pronounced line broadening for \(R < 1.5\ {{{{{\rm{nm}}}}}}\) vs. the size-distribution function \(\bar{g}\left(R\right)\) and the corresponding \(\bar{f}(\lambda )\) spectrum with a significant linewidth narrowing for the large-\(R\) region near \({R}_{{{{{{\rm{c}}}}}}}\) (the onset of the PL blue shift, \(13.75\ {{{{{\rm{nm}}}}}}\) for MAPbBr3). c Symmetric Lorentzian PL-\(\omega\) spectrum \(I(\omega )\) vs. asymmetric pseudo-Lorentzian PL-\(\lambda\) spectrum \(I(\lambda )\) for \({D}_{p} > \) exciton Bohr diameter (\(\approx 9\ {{{{{\rm{nm}}}}}}\) for MAPbBr3).

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