Proceedings of nanoGe September Meeting 2017 (NFM17)
Publication date: 20th June 2016
Semiconductor nanoheterostructures are of high interest due to the wide range of possibilities they offer for band structure engineering. Confinement or separation of excited charge carriers is employed to optimise photoluminescence, carrier extraction, upconversion, carrier multiplication, or optical gain.[1-3] The nature of the interfaces makes an integral contribution to the resulting electronic structure: while lattice mismatch exerts strain on the crystal lattice alloying between the adjacent materials releases this pressure.[4-7] Both effects may distort the band structure away from the simple step function that is often assumed as first approximation of the system.
We present recent results on the formation of interfaces between two II-VI semiconductors in colloidal nanocrystals. Shell formation or annealing at high temperatures is used to promote mixing of the two phases at the interface. We use transient absorption spectroscopy to observe the effects on charge carrier relaxation and extraction.[8] In core/shell/shell nanocrystals electron scavengers were employed to map the extent of alloying, which has strong implications on synthesis design for specific applications.
In nanorods the potential landscape across an axial heterojunction will dominate carrier relaxation. In these anisotropic systems the axial interface also competes with the potential step at the particle surface. We present evidence that suggests retarded carrier cooling across a CdTe/CdS type-II junction and models that explain these observations. A full characterisation of the electronic state from which the charges relax is highly relevant for applications such as two photon upconversion or as buildung blocks for nanoelectronic devices.[3]
[1] de Mello Donegá, Chem. Soc. Rev. 2011, 40, 1512-1546.
[2] Boldt, Kirkwood, Beane, Mulvaney, Chem. Mater. 2013, 25, 4731-4738.
[3] Deutsch, Neeman, Oron, Nat. Nanotech. 2013, 8, 649-653.
[4] Christodoulou, Rajadell, Casu, Vaccaro, Grim, Genovese, Manna, Climente, Meinardi, et al., Nat. Commun. 2015, 6, 1-8.
[5] Boldt, Schwarz, Kirkwood, Smith, Mulvaney, J. Phys. Chem. C 2014, 118, 13276-13284.
[6] Boldt, Ramanan, Chanaewa, Werheid, Eychmüller, J. Phys. Chem. Lett. 2015, 6, 2590-2597.
[7] Boldt, Z. Phys. Chem. 2017, 231, 77-92.
[8] Zeng, Kirkwood, Mulvaney, Boldt, Smith, Nanoscale 2016, 8, 10380-10387.
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.