Breaking Forbidden Transitions for Emission of Self-Trapped Excitons in Two Dimensional (F2CHCH2NH3)2CdBr4 Perovskite through Pb Alloying

In this work, a new two-dimensional Cd-based (F2CHCH2NH3)2CdBr4 perovskite
(Cd–P)
with indirect bandgap and a direct Pb-based (F2CHCH2NH3)2PbBr4 (Pb–P)
are successfully synthesized with isostructural features. Compared
to the blueish white light emission of Pb–P, almost no white
light can be observed for Cd–P due to the forbidden transition
of self-trapped exciton (STE) emission. Interestingly, the white light
emission of CdxPb1–x–P (x represents the feed
ratio of Cd) is significantly improved with the photoluminescence
(PL) quantum yield (QY) raising from

在本项研究中，成功合成了具有间接带隙的新型二维铯基钙钛矿 (F2CHCH2NH3)2CdBr4 (Cd–P)，以及与其结构相似的直接带隙铅基钙钛矿 (F2CHCH2NH3)2PbBr4 (Pb–P)。与Pb–P呈现的淡蓝色白光发射相比，Cd–P由于自陷激子发射的禁带跃迁，几乎不发出白光。值得注意的是，随着光致发光量子产率 (PL QY) 的显著提升，CdxPb1–x–P（x代表铯的投料比）的白光发射性能得到了显著改善。