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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 22: Perovskite and Photovoltaics II (joint session HL/KFM)

KFM 22.10: Talk

Thursday, March 21, 2024, 12:00–12:15, EW 203

Damping the phase segregation in mixed halide perovskites: Influence of X-site anion — •Maria Azhar — Universitz of Konstanz, Konstanz, Germany

This study reveals that phase segregation becomes more prominent on decreasing bromine content in mixed halide CsPbBr3-xClx perov*skites, when bromine content is 50NCs have been synthesized to mitigate the phase segregation. The grain size of the synthesized NCs exists in the range of 20*25 nm. The selected area electron diffraction exhibits the faint rings of the CsPbBr1.5Cl1.5 indicating the presence of defects in NCs and the X-rays diffraction analysis confirms the NCs exist in monoclinic crystal structure. Mixed halides perovskites have same crystal structure but exhibit a slight shift in 2θ values. The trend in stability follows the order as, CsPbBr3-xClx > CsPbCl3 > CsPbBr3 that is estimated by the values of octahedral factor (µ) and tolerance factor (t). The UV*Vis and steady-state photoluminescence (PL) analysis depict a blue-shift in the spectra by substituting bromine with chlorine in CsPbBr3. The PL kinetics analysis predicts the CsPbBr2.5Cl0.5 exhibits the longest average PL lifetime amongst all other CsPbBr3-xClx perovskites NCs. Our study provides insights in designing stable mixed halides perovskites by suppressing the phase segregation.

Keywords: Phase segregation; Mixed halides; perovskites nanocrystalls; Triple halide perovskites; photoluminiscence analysis