Copper Iron Chalcogenide Nanocrystals: Spectroscopy and Devices

Anumol s^a, Biswajit Bhattacharyya^a, V. V. R. Kishore^a, Abhinav Kumar^a, Guru Pratheep Rajasekar^a, D. D. Sarma^a, Anshu Pandey^a

^aSolid State and Structural Chemistry Unit (SSCU), Indian Institute of Science, IN, Bangalore, Bengaluru, India

Materials for Sustainable Development Conference (MATSUS)
Proceedings of nanoGe Fall Meeting19 (NFM19)

#NCFun19. Fundamental Processes in Semiconductor Nanocrystals

Berlin, Germany, 2019 November 3rd - 8th

Organizers: Ivan Infante and Jonathan Owen

Oral, Anumol s, presentation 333
DOI: https://doi.org/10.29363/nanoge.nfm.2019.333
Publication date: 18th July 2019

CuFeS2 quantum dots (QDs) have emerged as promising alternative to conventional lead and cadmium based QDs in recent years, courtesy of their narrow band gap and environmentally benign nature [1]. However, the full potential of this material remains unrealized because of the lingering doubts regarding their true nature. For instance, despite being a semiconductor, CuFeS2 QDs bear a striking resemblance to gold nanoparticles. The similarities extend all the way from the purple color of the QD solution and the metallic golden luster of the QD films to even the optical absorption spectrum of the QD solution. In particular, there is a bump at ~500 nm in the absorbance spectra of the QDs which look very similar to the localized surface plasmon resonance (LSPR) in gold nanoparticles. The literature reports on this feature, however, are conflicting and this band has been variously assigned to a LSPR as well as to an intermediate band by different researchers [2, 3]. A material which can support a LSPR could be useful for charge transport, while a material with an intermediate band could find direct uses in light harvesting. Given the vastly different implications of either of the two interpretations, it is quite necessary to understand the real nature of the 500 nm feature; i.e. whether it’s a LSPR or an intermediate band. Here, I will briefly describe the various techniques, namely, optical, ultrafast and electrical measurements undertaken by us to understand the true nature of the 500 nm feature and hence the material [4].

References:

[1] Bhattacharyya, B.; Pandey, A. CuFeS2 Quantum Dots and Highly Luminescent CuFeS2 Based Core/Shell Structures: Synthesis, Tunability, and Photophysics J. Am. Chem. Soc. 2016, 138, 10207−10213

[2] Gabka, G.; Bujak, P.; Ostrowski, A.; Tomaszewski, W.; Lisowski, W.; Sobczak, J. W.; Pron, A. Cu−Fe−S Nanocrystals Exhibiting Tunable Localized Surface Plasmon Resonance in the Visible to NIR Spectral Ranges. Inorg. Chem. 2016, 55, 6660−6669.

[3] Ghosh, S.; Avellini, T.; Petrelli, A.; Kriegel, I.; Gaspari, R.; Almeida, G.; Bertoni, G.; Cavalli, A.; Scotognella, F.; Pellegrino, T.; Manna, L. Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency. Chem. Mater. 2016, 28, 4848−4858

[4] Sugathan, A.; Bhattacharyya, B.; Kishore, V. V. R.; Kumar, A.; Rajasekar, G. P.; Sarma, D. D.; Pandey, A. Why Does CuFeS2 Resemble Gold? J. Phys. Chem. Lett. 2018, 9, 696−701

Acknowledgements:

We acknowledge DST and ISRO-IISc STC for funding

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