TY - JOUR
T1 - The Origin of Broad Emission in ⟨100»Two-Dimensional Perovskites
T2 - Extrinsic vs Intrinsic Processes
AU - Kahmann, Simon
AU - Meggiolaro, Daniele
AU - Gregori, Luca
AU - Tekelenburg, Eelco K.
AU - Pitaro, Matteo
AU - Stranks, Samuel D.
AU - De Angelis, Filippo
AU - Loi, Maria A.
N1 - Funding Information:
Arjen Kamp and Teodor Zaharia are thanked for technical support. S.K. is grateful for a postdoctoral fellowship (91793256) from the German Academic Foreign Service (DAAD). This work was financed through the Materials for Sustainability (Mat4Sus) programme (739.017.005) of The Netherlands Organisation for Scientific Research (NWO).
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/12/9
Y1 - 2022/12/9
N2 - 2D metal halide perovskites can show narrow and broad emission bands (BEs), and the latter's origin is hotly debated. A widespread opinion assigns BEs to the recombination of intrinsic self-trapped excitons (STEs), whereas recent studies indicate they can have an extrinsic defect-related origin. Here, we carry out a combined experimental-computational study into the microscopic origin of BEs for a series of prototypical phenylethylammonium-based 2D perovskites, comprising different metals (Pb, Sn) and halides (I, Br, Cl). Photoluminescence spectroscopy reveals that all of the compounds exhibit BEs. Where not observable at room temperature, the BE signature emerges upon cooling. By means of DFT calculations, we demonstrate that emission from halide vacancies is compatible with the experimentally observed features. Emission from STEs may only contribute to the BE in the wide-band-gap Br- and Cl-based compounds. Our work paves the way toward a complete understanding of broad emission bands in halide perovskites that will facilitate the fabrication of efficient narrow and white light emitting devices.
AB - 2D metal halide perovskites can show narrow and broad emission bands (BEs), and the latter's origin is hotly debated. A widespread opinion assigns BEs to the recombination of intrinsic self-trapped excitons (STEs), whereas recent studies indicate they can have an extrinsic defect-related origin. Here, we carry out a combined experimental-computational study into the microscopic origin of BEs for a series of prototypical phenylethylammonium-based 2D perovskites, comprising different metals (Pb, Sn) and halides (I, Br, Cl). Photoluminescence spectroscopy reveals that all of the compounds exhibit BEs. Where not observable at room temperature, the BE signature emerges upon cooling. By means of DFT calculations, we demonstrate that emission from halide vacancies is compatible with the experimentally observed features. Emission from STEs may only contribute to the BE in the wide-band-gap Br- and Cl-based compounds. Our work paves the way toward a complete understanding of broad emission bands in halide perovskites that will facilitate the fabrication of efficient narrow and white light emitting devices.
UR - http://www.scopus.com/inward/record.url?scp=85141498745&partnerID=8YFLogxK
U2 - 10.1021/acsenergylett.2c02123
DO - 10.1021/acsenergylett.2c02123
M3 - Article
AN - SCOPUS:85141498745
SN - 2380-8195
VL - 7
SP - 4232
EP - 4241
JO - ACS Energy Letters
JF - ACS Energy Letters
IS - 12
ER -