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Nano Research 2019, 12(1): 77-84 https://doi.org/10.1007/s12274-018-2183-9
Research Article | Issue | Published: 30 August 2018

Surface molecular doping of all-inorganic perovskite using zethrenes molecules

Show Author's Information Arramel1( ),  Hu Pan2,  Aozhen Xie3,4,5,  Songyan Hou3,4,  Xinmao Yin1,6,  Chi Sin Tang1,6,7,  Nguyen T. Hoa3,  Muhammad D. Birowosuto3,  Hong Wang3,4,  Cuong Dang3,4,5( ),  Andrivo Rusydi1,6,8,  Andrew T. S. Wee1,9,10,  Jishan Wu2( )
Department of Physics,National University of Singapore,2 Science Drive 3,Singapore,117542,Singapore;
Department of Chemistry,National University of Singapore,3 Science Drive 3,Singapore,117543,Singapore;
CINTRA UMI CNRS/NTU/THALES 3288,Research Techno Plaza,50 Nanyang Drive, Level 6, Border X Block,Singapore,637553,singapore;
School of Electrical and Electronic Engineering,Nanyang Technological University,50 Nanyang Avenue,Singapore,639798,Singapore;
Energy Research Institute @NTU (ERI@N),Nanyang Technological University,Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive,Singapore,637553,Singapore;
Singapore Synchrotron Light Source,National University of Singapore,5 Research Link,Singapore,1176033,Singapore;
NUS Graduate School for Integrative Sciences and Engineering (NGS),National University of Singapore,Singapore,117456,Singapore;
NUSNNI-NanoCore,National University of Singapore,Singapore,117411,Singapore;
Institute of Materials Research & Engineering (IMRE),Agency for Science,Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis,Singapore,138634,Singapore;
Centre for Advanced 2D Materials,National University of Singapore,Block S14, Level 6, 6 Science Drive 2,Singapore,117546,Singapore
Keywords:
perovskite, zethrene, photoelectron spectroscopy, near edge X-ray absorption fine structure and molecular doping
Topics:
Atomic physicsBromine compoundsCesium compoundsCharge transferElectronic propertiesHeterojunctionsPerovskitePhotoelectron spectroscopyPhotoelectronsPhotonsSemiconductor dopingSingle crystalsSpectroscopic analysisVan der Waals forcesX-ray absorption
Cite this article:
Arramel, Pan H, Xie A, et al. Surface molecular doping of all-inorganic perovskite using zethrenes molecules. Nano Research, 2019, 12(1): 77-84. https://doi.org/10.1007/s12274-018-2183-9
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Abstract Full text Electronic supplementary material About this article

We present an optical and photoelectron spectroscopic study to elucidate the interfacial electronic properties of organic-inorganic semiconductor heterojunctions formed in a kinetically blocked heptazethrene triisopropylsilyl ethynylene (HZ-TIPS) and its homologue, octazethrene (OZ-TIPS) on an all-inorganic perovskite cesium lead bromide (CsPbBr3) surface. The photoluminescence behavior of the underlying perovskites upon differing molecular doping conditions was examined. It turns out that the charge transfer dynamics of thermally-evaporated OZ-TIPS molecule exhibited a faster average lifetime than that of the HZ-TIPS case suggesting the importance of the biradical state in the former molecule. An interfacial dipole was formed at the interface due to the competing interaction between the dispersion force of the bulky TIPS-substituent group and the attractive van der Waals interaction at the first few layers. Photoemission spectroscopy of the physisorbed HZ-TIPS shows chemical shifts, which indicates electron transfer from HZ-TIPS molecules to the CsPbBr3 perovskite single crystal. In contrast, the adsorbed OZ-TIPS molecular layer on CsPbBr3 demonstrates the opposite trend indicating a hole transfer process. The average molecular orientation as determined by near edge X-ray absorption fine structure (NEXAFS) suggests that the HZ-TIPS molecular plane is generally lifted with respect to the perovskite surface. We suggest that the nature of the closed-shell electronic ground state of HZ-TIPS could contribute to the formation of interfacial dipole at the molecule/perovskite interface.


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Electronic supplementary material
About this article

Surface molecular doping of all-inorganic perovskite using zethrenes molecules

Show Author's information Arramel1( ), Hu Pan2, Aozhen Xie3,4,5, Songyan Hou3,4, Xinmao Yin1,6, Chi Sin Tang1,6,7, Nguyen T. Hoa3, Muhammad D. Birowosuto3, Hong Wang3,4, Cuong Dang3,4,5( ), Andrivo Rusydi1,6,8, Andrew T. S. Wee1,9,10, Jishan Wu2( )
Department of Physics,National University of Singapore,2 Science Drive 3,Singapore,117542,Singapore;
Department of Chemistry,National University of Singapore,3 Science Drive 3,Singapore,117543,Singapore;
CINTRA UMI CNRS/NTU/THALES 3288,Research Techno Plaza,50 Nanyang Drive, Level 6, Border X Block,Singapore,637553,singapore;
School of Electrical and Electronic Engineering,Nanyang Technological University,50 Nanyang Avenue,Singapore,639798,Singapore;
Energy Research Institute @NTU (ERI@N),Nanyang Technological University,Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive,Singapore,637553,Singapore;
Singapore Synchrotron Light Source,National University of Singapore,5 Research Link,Singapore,1176033,Singapore;
NUS Graduate School for Integrative Sciences and Engineering (NGS),National University of Singapore,Singapore,117456,Singapore;
NUSNNI-NanoCore,National University of Singapore,Singapore,117411,Singapore;
Institute of Materials Research & Engineering (IMRE),Agency for Science,Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis,Singapore,138634,Singapore;
Centre for Advanced 2D Materials,National University of Singapore,Block S14, Level 6, 6 Science Drive 2,Singapore,117546,Singapore

Abstract

We present an optical and photoelectron spectroscopic study to elucidate the interfacial electronic properties of organic-inorganic semiconductor heterojunctions formed in a kinetically blocked heptazethrene triisopropylsilyl ethynylene (HZ-TIPS) and its homologue, octazethrene (OZ-TIPS) on an all-inorganic perovskite cesium lead bromide (CsPbBr3) surface. The photoluminescence behavior of the underlying perovskites upon differing molecular doping conditions was examined. It turns out that the charge transfer dynamics of thermally-evaporated OZ-TIPS molecule exhibited a faster average lifetime than that of the HZ-TIPS case suggesting the importance of the biradical state in the former molecule. An interfacial dipole was formed at the interface due to the competing interaction between the dispersion force of the bulky TIPS-substituent group and the attractive van der Waals interaction at the first few layers. Photoemission spectroscopy of the physisorbed HZ-TIPS shows chemical shifts, which indicates electron transfer from HZ-TIPS molecules to the CsPbBr3 perovskite single crystal. In contrast, the adsorbed OZ-TIPS molecular layer on CsPbBr3 demonstrates the opposite trend indicating a hole transfer process. The average molecular orientation as determined by near edge X-ray absorption fine structure (NEXAFS) suggests that the HZ-TIPS molecular plane is generally lifted with respect to the perovskite surface. We suggest that the nature of the closed-shell electronic ground state of HZ-TIPS could contribute to the formation of interfacial dipole at the molecule/perovskite interface.

Keywords: perovskite, zethrene, photoelectron spectroscopy, near edge X-ray absorption fine structure and molecular doping

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Publication history
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Acknowledgements

Publication history

Received: 23 May 2018
Revised: 18 August 2018
Accepted: 20 August 2018
Published: 30 August 2018
Issue date: January 2019

Copyright

© Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Acknowledgements

Acknowledgements

We acknowledge Wong How Kwong for the assistance during UPS measurements. Xiaojiang Yu is appreciated for his technical support in the Singapore Synchrotron Light Source (SSLS). We note synchrotron facility plays indispensable part in this work as a National Research Infrastructure under the National Research Foundation Singapore. This work is financially supported by several funding agencies. Thus, authors are acknowledged a research grant from MOE Tier 3 programme (No. MOE2014-T3-1-004). The work at SSLS is supported by Singapore National Research Foundation under its Competitive Research Funding (No. NRF-CRP 8-2011-06), MOE-AcRF Tier-2 (No. MOE2015-T2-1-099), FRC and PHC Merlion. NTU authors acknowledge the Ministry of Education funding (No. MOE2016-T2-1-052).

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