Extrinsic nature of the broad photoluminescence in lead iodide-based Ruddlesden-Popper perovskites
Extrinsic nature of the broad photoluminescence in lead iodide-based Ruddlesden-Popper perovskites
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DOI：
10.1038/s41467-020-15970-x
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发表时间：
2020-05-11
影响因子：
16.6
通讯作者：
Loi, Maria A.
中科院分区：
文献类型：
--
作者：
Kahmann, Simon;Tekelenburg, Eelco K.;Loi, Maria A.
Ruddlesden-Popper 型二维金属卤化物钙钛矿最近成为钙钛矿研究的关注焦点，因为它们具有发光和稳定 3D 对应物的潜力。该领域已广泛将具有大斯托克斯位移的宽发光归因于自俘获激子，这些激子是由于这些化合物中强烈的载流子-声子相互作用而形成的。相反，通过研究两种类型的碘化铅基单晶的行为，我们在这里强调了它们宽带发射的外在起源。如带隙下方激发所示，晶体块中的带隙内态是造成宽发射的原因。有了这种见解，我们进一步了解了低维钙钛矿的发射特性，并对金属卤化物钙钛矿和相关化合物中宽带发射归因于自俘获激子的普遍性提出了质疑。 Ruddlesden-Popper 型卤化物钙钛矿正引起人们的兴趣，但其宽带发射的起源仍然难以捉摸。卡曼等人在这里。表明带隙内态，而不是通常认为的自俘获激子，是晶体样品中宽带发射的原因。
Two-dimensional metal halide perovskites of Ruddlesden-Popper type have recently moved into the centre of attention of perovskite research due to their potential for light generation and for stabilisation of their 3D counterparts. It has become widespread in the field to attribute broad luminescence with a large Stokes shift to self-trapped excitons, forming due to strong carrier-phonon interactions in these compounds. Contrarily, by investigating the behaviour of two types of lead-iodide based single crystals, we here highlight the extrinsic origin of their broad band emission. As shown by below-gap excitation, in-gap states in the crystal bulk are responsible for the broad emission. With this insight, we further the understanding of the emission properties of low-dimensional perovskites and question the generality of the attribution of broad band emission in metal halide perovskite and related compounds to self-trapped excitons. The Ruddlesden-Popper type of halide perovskites are gaining interest but the origin of their broad band emission remains elusive. Here Kahmann et al. suggest that in-gap states, instead of the commonly believed self-trapped excitons, are responsible for the broad band emission in crystalline samples.