Investigation of photocarrier losses in pyrite (FeS2) film consisting single crystal nanocubes

Sudhanshu Shukla; Thirumany Sritharan; Xiong Qihua; Tze Chien Sum; Guichuan Xing; Nripan Mathews; Hu Ge; Thirumalai Venkatesan; Sinu Mathew; Su Zhenghua; Venkatram Nalla

doi:10.11159/icnnfc17.118

Investigation of photocarrier losses in pyrite (FeS₂) film consisting single crystal nanocubes

Sudhanshu Shukla, Thirumany Sritharan^*, Xiong Qihua, Tze Chien Sum, Guichuan Xing, Nripan Mathews, Hu Ge, Thirumalai Venkatesan, Sinu Mathew, Su Zhenghua, Venkatram Nalla

^*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

2 Citations (Scopus)

Abstract

Successful extraction of photo excited carriers from a photo active material is key towards a successful PV device. The high losses exhibited by a device with pyrite as the active layer has been noted previously but never investigated systematically to understand the photo physics and the carrier loss mechanisms to improve its performance. Here we report a detailed characterization of a film made using (100) terminated, pure pyrite single crystal nano cubes. Using ultrafast transient absorption spectroscopy we found fast carrier localization of photo excited carriers to indirect band edge and shallow trap states with characteristic decay time of 1.8 picoseconds, followed by relaxation to deep states and recombination of trapped carriers with long characteristic decay times of 50-990 nanoseconds. Its optical absorption characteristics correlate to a disordered semiconductor. Temperature dependent electrical resistivity exhibits a Mott - variable range hopping (VRH) type conduction mechanism consistent with the presence of high density of defect states. An electron band model with midgap defect states is formulated that could explain all the observed phenomena.

Original language	English
Title of host publication	Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017
Publisher	Avestia Publishing
ISBN (Print)	9781927877289
DOIs	https://doi.org/10.11159/icnnfc17.118
Publication status	Published - 2017
Externally published	Yes
Event	Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017 - Barcelona, Spain Duration: Apr 4 2017 → Apr 6 2017

Publication series

Name	World Congress on Recent Advances in Nanotechnology
ISSN (Electronic)	2371-5308

Conference

Conference	Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017
Country/Territory	Spain
City	Barcelona
Period	4/4/17 → 4/6/17

Bibliographical note

Publisher Copyright:
© Avestia Publishing, 2017.

ASJC Scopus Subject Areas

Biotechnology
Biomedical Engineering
Mechanical Engineering
Management, Monitoring, Policy and Law
Pollution
Biomaterials
Modelling and Simulation
Histology

Keywords

Carrier dynamics
Magnetization
Nanocubes
Optical transient absorption spectroscopy
Variable range hopping

Access to Document

10.11159/icnnfc17.118

Cite this

Shukla, S., Sritharan, T., Qihua, X., Sum, T. C., Xing, G., Mathews, N., Ge, H., Venkatesan, T., Mathew, S., Zhenghua, S., & Nalla, V. (2017). Investigation of photocarrier losses in pyrite (FeS₂) film consisting single crystal nanocubes. In Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017 (World Congress on Recent Advances in Nanotechnology). Avestia Publishing. https://doi.org/10.11159/icnnfc17.118

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title = "Investigation of photocarrier losses in pyrite (FeS2) film consisting single crystal nanocubes",

abstract = "Successful extraction of photo excited carriers from a photo active material is key towards a successful PV device. The high losses exhibited by a device with pyrite as the active layer has been noted previously but never investigated systematically to understand the photo physics and the carrier loss mechanisms to improve its performance. Here we report a detailed characterization of a film made using (100) terminated, pure pyrite single crystal nano cubes. Using ultrafast transient absorption spectroscopy we found fast carrier localization of photo excited carriers to indirect band edge and shallow trap states with characteristic decay time of 1.8 picoseconds, followed by relaxation to deep states and recombination of trapped carriers with long characteristic decay times of 50-990 nanoseconds. Its optical absorption characteristics correlate to a disordered semiconductor. Temperature dependent electrical resistivity exhibits a Mott - variable range hopping (VRH) type conduction mechanism consistent with the presence of high density of defect states. An electron band model with midgap defect states is formulated that could explain all the observed phenomena.",

keywords = "Carrier dynamics, Magnetization, Nanocubes, Optical transient absorption spectroscopy, Variable range hopping",

author = "Sudhanshu Shukla and Thirumany Sritharan and Xiong Qihua and Sum, {Tze Chien} and Guichuan Xing and Nripan Mathews and Hu Ge and Thirumalai Venkatesan and Sinu Mathew and Su Zhenghua and Venkatram Nalla",

note = "Publisher Copyright: {\textcopyright} Avestia Publishing, 2017.; Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017 ; Conference date: 04-04-2017 Through 06-04-2017",

year = "2017",

doi = "10.11159/icnnfc17.118",

language = "English",

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Shukla, S, Sritharan, T, Qihua, X, Sum, TC, Xing, G, Mathews, N, Ge, H, Venkatesan, T, Mathew, S, Zhenghua, S & Nalla, V 2017, Investigation of photocarrier losses in pyrite (FeS₂) film consisting single crystal nanocubes. in Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017. World Congress on Recent Advances in Nanotechnology, Avestia Publishing, Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017, Barcelona, Spain, 4/4/17. https://doi.org/10.11159/icnnfc17.118

Investigation of photocarrier losses in pyrite (FeS₂) film consisting single crystal nanocubes. / Shukla, Sudhanshu; Sritharan, Thirumany; Qihua, Xiong et al.
Proceedings of the 2nd World Congress on Recent Advances in Nanotechnology, RAN 2017. Avestia Publishing, 2017. (World Congress on Recent Advances in Nanotechnology).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

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T1 - Investigation of photocarrier losses in pyrite (FeS2) film consisting single crystal nanocubes

AU - Shukla, Sudhanshu

AU - Sritharan, Thirumany

AU - Qihua, Xiong

AU - Sum, Tze Chien

AU - Xing, Guichuan

AU - Mathews, Nripan

AU - Ge, Hu

AU - Venkatesan, Thirumalai

AU - Mathew, Sinu

AU - Zhenghua, Su

AU - Nalla, Venkatram

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N2 - Successful extraction of photo excited carriers from a photo active material is key towards a successful PV device. The high losses exhibited by a device with pyrite as the active layer has been noted previously but never investigated systematically to understand the photo physics and the carrier loss mechanisms to improve its performance. Here we report a detailed characterization of a film made using (100) terminated, pure pyrite single crystal nano cubes. Using ultrafast transient absorption spectroscopy we found fast carrier localization of photo excited carriers to indirect band edge and shallow trap states with characteristic decay time of 1.8 picoseconds, followed by relaxation to deep states and recombination of trapped carriers with long characteristic decay times of 50-990 nanoseconds. Its optical absorption characteristics correlate to a disordered semiconductor. Temperature dependent electrical resistivity exhibits a Mott - variable range hopping (VRH) type conduction mechanism consistent with the presence of high density of defect states. An electron band model with midgap defect states is formulated that could explain all the observed phenomena.

AB - Successful extraction of photo excited carriers from a photo active material is key towards a successful PV device. The high losses exhibited by a device with pyrite as the active layer has been noted previously but never investigated systematically to understand the photo physics and the carrier loss mechanisms to improve its performance. Here we report a detailed characterization of a film made using (100) terminated, pure pyrite single crystal nano cubes. Using ultrafast transient absorption spectroscopy we found fast carrier localization of photo excited carriers to indirect band edge and shallow trap states with characteristic decay time of 1.8 picoseconds, followed by relaxation to deep states and recombination of trapped carriers with long characteristic decay times of 50-990 nanoseconds. Its optical absorption characteristics correlate to a disordered semiconductor. Temperature dependent electrical resistivity exhibits a Mott - variable range hopping (VRH) type conduction mechanism consistent with the presence of high density of defect states. An electron band model with midgap defect states is formulated that could explain all the observed phenomena.

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