Universität zu Köln

Dolatyari, Mahboubeh, Rostami, Ali, Mathur, Sanjay and Klein, Axel ORCID: 0000-0003-0093-9619 (2019). Trap engineering in solution processed PbSe quantum dots for high-speed MID-infrared photodetectors. J. Mater. Chem. C, 7 (19). S. 5658 - 5670. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 2050-7534

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Abstract

The ongoing quest to find methods to control the trap states in solution processed nanostructures (trap engineering) will revolutionise the applications of nanomaterials for optoelectronic purposes. In this paper, we present a new combined experimental/theoretical approach (molecular orbital theory) allowing a new view on trap engineering of nanostructures for applications in photodetectors. PbSe quantum dots (QDs) of about 30 nm diameter were prepared in a solution-based process from lead iodide (PbI2) and chloride (PbCl2), while using lead acetate (PbOAc2) reliably gave particles of about 200 nm in size under the same conditions. Comparison of the dangling acetate (OAc-) versus the spherical monoatomic surface ligands chloride (Cl-) and iodide (I-) and varying the covalent/ionic character of the particle-surface ligand (ionic: OAc- > Cl- > I-: covalent) bond allowed an interesting insight into what governs the trap states. Density functional theory (DFT) calculations are used to study band structures and density of states and show trap states localised within the bandgap moving to the conduction or valence band upon interaction of surface metal atoms with the surface ligands. Infrared detectors based on these materials are fabricated and allowed high-speed mid-infrared photo-detection with 100 ns rise and 110 ns fall response times.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Dolatyari, Mahboubeh UNSPECIFIED UNSPECIFIED UNSPECIFIED Rostami, Ali UNSPECIFIED UNSPECIFIED UNSPECIFIED Mathur, Sanjay UNSPECIFIED UNSPECIFIED UNSPECIFIED Klein, Axel UNSPECIFIED orcid.org/0000-0003-0093-9619 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-147997
DOI:	10.1039/c8tc06093b
Journal or Publication Title:	J. Mater. Chem. C
Volume:	7
Number:	19
Page Range:	S. 5658 - 5670
Date:	2019
Publisher:	ROYAL SOC CHEMISTRY
Place of Publication:	CAMBRIDGE
ISSN:	2050-7534
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INFRARED PHOTODETECTORS; SOLAR-CELLS; LOW-NOISE; HIGH-GAIN; HALIDE; NANOCRYSTALS; NANOPARTICLE; PASSIVATION; FABRICATION Multiple languages Materials Science, Multidisciplinary; Physics, Applied Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/14799