Optical tunability and disorder induced effects in 2D-layered and 3D organic-inorganic perovskite pseudobinary alloys

Jean-Sébastien Lauret^a, Yi Wei^a, Khaoula Jemli^a, Emmanuelle Deleporte^a, Gaëtan Lanty^a, Joël Leymarie^b, Jacky Even^c

^aLAC, Ecole Normale Supérieure de Cachan, 61, avenue du Président Wilson, Cachan, 94235, France

^bLASMEA, Université Balise Pascal, Clermont-Ferrand II, Les Cézeaux, 63177 Aubière, France

^cFOTON, INSA, Université Européenne de Bretagne, 35 708 Rennes, France

Proceedings of International Conference Solution processed Semiconductor Solar Cells (SSSC14)

Organizers: Henry Snaith and Samuel Stranks

Poster, Emmanuelle Deleporte, 062
Publication date: 1st July 2014

Organic-inorganic hybrid semiconductors based on metal halide units have attracted attention due to their interesting structural and optical properties. In particular, attention has been focused on the 2D-layered organic-inorganic perovskite semiconductors (R-NH3)2PbX4 with R an organic group and X the halide (Cl-, Br-, I-) because of their application in emitting optical devices [1,2] and recently on 3D perovskites such as CH3NH3PbX3 which reveal particularly convenient for the photovoltaïc applications [3-5]. Among several advantages, these materials are remarkable due to their excitonic properties: for example the 2D perovskites form self-assembled ordered quantum well structures, in which the excitons are strongly confined in the very thin inorganic wells PbX62-, resulting in a very large exciton binding energy of a few hundred of meV. Understanding the nature of the excitons in perovskites is crucial to optimize the opto-electronic devices, the emitting ones requiring strong excitons at room temperature as well as the absorbing ones where the exciton has to be separated to generate free carriers.

We focus here our attention on 2D mixed perovskites (C6H5-C2H4-NH3)2PbZ4(1-x)Y4x, and 3D mixed perovskites CH3NH3PbZ3-xYx where Z, Y = I, Br or Cl. Firstly, we show that 2D and 3D mixed perovskites afford similar continuous optical tunability at room temperature. Secondly, studying experimentally the disorder induced effects on the optical properties, we demonstrate that they can be considered as pseudobinary alloys, exactly like Ga1-xAlxAs, Cd1-xHgxTe inorganic semiconductors. We develop a theoretical analysis which allows to describe the influence of alloying on the excitonic properties of perovskite molecular crystals. Despite a large binding energy of several 100 meV, the 2D excitons present a Wannier character rather than a Frenkel character. The small inhomogeneous broadening reported in 3D hybrid alloyed compounds is similarly consistent with delocalized electron hole pairs at room temperature rather than strongly localized excitons.

References:

[1] D.B. Mitzi, K. Chondoudris and C. Kagan, IBM J. Res. Dev. 45, 29 (2001)

[2] G. Lanty, J.S. Lauret, D. Byrne, E. Deleporte, S. Bouchoule and X. Lafosse, Appl. Phys. Lett. 93, 81101 (2008)

[3] J. Burschka, N. Pellet, S. J. Moon, R. Humphry-Baker, P. Gao, M. K. Nazeeruddin, and M. Grätzel, Nature 499, 316 (2013)

[4] M. Liu, M. B. Johnston, and H. J. Snaith, Nature 501, 395 (2013)

[5] J. H. Noh, S. H. Im, J. H. Heo, T. N. Mandal, and S. I. Seok, Nano Lett. 13, 1764 (2013)

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.