CsPbX3 (X = Cl, Br, I) Perovskite Nanocrystals: Beyond CdSe Quantum Dots

Angshuman Nag^a, Pankaj Mandal^a, Yettapu Gurivi Reddy^a, Ganesh B. Markad^a, Vikash Kumar Ravi^a, Abhishek Swarnkar^a, Ramya Chulliyil^b, Arindam Chowdhury^b

^aIndian Institute of Science Education and Research (IISER), Pune, IN, Pune, Maharastra 411008, India, Pune, India

^bDepartment of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India

Materials for Sustainable Development Conference (MATSUS)
Proceedings of September Meeting 2016 (NFM16)

Berlin, Germany, 2016 September 5th - 13th

Organizers: Marin Alexe, Enrique Cánovas, Celso de Mello Donega, Ivan Infante, Thomas Kirchartz, Maksym Kovalenko, Federico Rosei, Lukas Schmidt-Mende, Laurens Siebbeles, Peter Strasser, Teodor K Todorov, Roel van de Krol and Ulrike Woggon

Oral, Angshuman Nag, presentation 136
Publication date: 14th June 2016

Colloidal quantum dots (cQDs), such as those based on CdSe are widely known for their interesting electronic, optical andoptoelectronic properties. In the beginning of 2015, Protesescu et al¹ reported CsPbX₃ perovskite nanocrystals with ~90% photoluminescence efficiency, suggesting that these perovskite nanocrystals have the possibility to perform better as an optoelectronic material compared to traditional cQDs like CdSe based ones. In this presentation, I will discuss our recent results showing (i) unique advantages in both ensemble and single-nanocrystal photluminescence of colloidal CsPbBr₃ nanocrystals compared to traditional CdSe cQDs,² (ii) the influence of halide composition on valence and conduction band edges, (iii) ultrafast terahertz (THz) spectroscopy results signifying surface defects do not trap charge carriers.

Colloidal CsPbBr₃ nanocrystals (11 nm) exhibit ~90% PL quantum yield with narrow (FWHM = 86 meV) spectral width. FWHM of a single-nanocrystal and ensemble are almost identical, ruling out the problem of size-distribution in photoluminescence broadening, along with batch-to-batch reproducibility of nanocrystals exhibiting photoluminescence peak within ±1 nm. Tuning of luminescence color across the visible region can be achieved by controlling halide composition, and our cyclic voltammetry results show that change in valence band maximum with halide composition is mainly responsible for the change in optical gap. However, conduction band minimum (CBM) also shift (though to a smaller extent) systematically with halide composition, suggesting contribution of X np orbital to the CBM is not negligible. Finally, CsPbBr₃ nanocrystals exhibit very high (~ 5000 cm²V^-1S^-1) THz carrier mobility within a nanocrystal suggesting minimal influence of the surface defects as mid-gap deep trap states.

Reference:

1. Protesescu, L.; Yakunin, S.; Bodnarchuk, M. I.; Krieg, F.; Caputo, R.; Hendon, C. H.; Yang, R. X.; Walsh, A.; Kovalenko, M. V. Nano Lett. 2015, 15, 3692.

2. Swarnkar, A; Chulliyil, R.; Ravi, V. K.; Irfanullah, M.; Chowdhury, A.; Nag A. Angew. Chem. Int. Ed. 2015, 53, 15424.

nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.

MATSUS

Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.

International Conference on Hybrid and Organic Photovoltaics

International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.

Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics

The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.

International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics

The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.