Raman Spectroscopy and Thermoelectric Characterization of Composite Thin Films of Cu2ZnSnS4 Nanocrystals Embedded in a Conductive Polymer PEDOT:PSS

Yevhenii Havryliuk; Volodymyr Dzhagan; Anatolii Karnaukhov; Oleksandr Selyshchev; Julia Hann; Dietrich R T Zahn

doi:10.3390/nano13010041

Raman Spectroscopy and Thermoelectric Characterization of Composite Thin Films of Cu₂ZnSnS₄ Nanocrystals Embedded in a Conductive Polymer PEDOT:PSS

Nanomaterials (Basel). 2022 Dec 22;13(1):41. doi: 10.3390/nano13010041.

Authors

Yevhenii Havryliuk^{1

2

3}, Volodymyr Dzhagan^{3

4}, Anatolii Karnaukhov³, Oleksandr Selyshchev^{1

2}, Julia Hann², Dietrich R T Zahn^{1

2}

Affiliations

¹ Semiconductor Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany.
² Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), 09126 Chemnitz, Germany.
³ V.E. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine, 03028 Kyiv, Ukraine.
⁴ Physics Department, Taras Shevchenko National University of Kyiv, 60 Volodymyrs'ka str., 01601 Kyiv, Ukraine.

Abstract

Cu₂ZnSnS₄ (CZTS) is an intensively studied potential solar cell absorber and a promising thermoelectric (TE) material. In the form of colloidal nanocrystals (NCs), it is very convenient to form thin films on various substrates. Here, we investigate composites of CZTS NCs with PEDOT:PSS, a widely used photovoltaics polymer. We focus on the investigation of the structural stability of both NCs and polymers in composite thin films with different NC-to-polymer ratios. We studied both pristine films and those subjected to flash lamp annealing (FLA) or laser irradiation with various power densities. Raman spectroscopy was used as the main characterization technique because the vibrational modes of CZTS NCs and the polymer can be acquired in one spectrum and thus allow the properties of both parts of the composite to be monitored simultaneously. We found that CZTS NCs and PEDOT:PSS mutually influence each other in the composite. The thermoelectric properties of PEDOT:PSS/CZTS composite films were found to be higher compared to the films consisting of bare materials, and they can be further improved by adding DMSO. However, the presence of NCs in the polymer deteriorates its structural stability when subjected to FLA or laser treatment.

Keywords: Cu2ZnSnS4 (CZTS); PEDOT:PSS; nanocrystals; thermoelectric properties.

Grants and funding

This research was funded by DFG Project ZA 146/45-1 and Alexander von Humbold Foundation, Ref 3.3-1212157-UKR-GF-P.