Proceedings of September Meeting 2016 (NFM16)
Publication date: 14th June 2016
Colloidal nanocrystals (NCs) of ternary semiconductors, such as CuInX2 (with X = S, Se and Te), are widely investigated as alternative for the toxic heavy-metal-based NCs (CdX and PbX), owing to the tunability of their optoelectronic properties through the visible to the near-infrared spectral window.[1] However, direct synthesis protocols for ternary NCs are limited because multiple precursor reactivities must be tuned simultaneously.[1] Cation exchange (CE) reactions have emerged as alternative for direct synthesis protocols, due to the post-synthetic control over the composition with size and shape preservation, which results in NCs otherwise not attainable.[2] In this way, we have been able to produce CuInS2 quantum dots[3] and CuInSe2/CuInS2 (CISe/CIS) dot-in-rod heterostructures,[4] using partial, self-limited In3+ for Cu+ cation exchange reactions, by taking advantage of the synthetic versatility of parent Cu2-xS and CdSe/CdS nanocrystals.
In this work, we study for the first time the carrier localization regime in ternary CISe/CIS hetero-nanocrystals. To this end, we synthesized a series of CdSe/CdS core/shell nanocrystals with variable core diameter (ranging from 2 nm to 5 nm) and shell thickness (2 to 6 CdS monolayers overgrown on each core size). Subsequently, these heteronanocrystals were used as templates and converted to the CuIn analogues by using a sequential cation exchange protocol (Cd2+ for Cu+ followed by partial, self-limited Cu+ for In3+). In this way, we can effectively tune the band offset between the CuInSe2 and CuInS2 segments, thereby affecting the carrier localization and exciton lifetimes. We study these CISe/CIS NCs with time-resolved photoluminescence decay measurements and find that the exciton lifetime depends strongly on the size/thickness of the different segments.
[1] J. Kolny-Olesiak, H. Weller, ACS Appl. Mater. Interfaces, 2013, 5, 12221.
[2] B. Beberwyck, Y. Surendranath, A. Alivisatos, J. Phys. Chem. C., 2013, 117, 19759.
[3] W. van der Stam et al., Chem. Mater., 2015, 27, 621.
[4] W. van der Stam et al., ACS Nano, 2015, 9, 11430.
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.
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.
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.