Proceedings of September Meeting 2016 (NFM16)
Publication date: 14th June 2016
As the average photon energy of solar radiation is well above the band gap energy of most photovoltaic materials, the role of “hot” states in the generation and extraction of free charge carriers is subject of ongoing discussion. It has been proposed that excess energy promotes the formation of free charge versus hot CT states, thereby by-passing low lying CT excitons. Also, recent work revealed a pronounced slow-down of free carrier motion, caused by the thermalization of photogenerated “hot” carriers in an inhomogeneous density of state distribution [1]. On the other hand, the JV-characteristics of organic solar cells can be well understand on the basis of steady state transport and recombination data [2], questioning a severe contribution of hot pathways to the photon-to-electron conversion in a working device.
This talk summarizes results on the role of excess energy in generating free charge, and on whether and how thermalization of photogenerated charge affects the dynamics of non-geminate recombination. We show that for a wide range of systems and illumination conditions, the efficiency and field-dependence of free charge generation is independent of excitation energy, ruling out a significant influence of excess energy on CT splitting [3]. Time delayed charge collection following pulsed illumination is then performed to study the dynamics of non-geminate recombination in a working solar cell. The data show non-geminate recombination to be indeed dispersive in some organic and hybrid solar cells [4], but with the steady state recombination kinetics being essentially determined by the recombination properties of thermalized free carriers.
[1] A. Melianas et al., Nat. Commun. 6, 8778 (2015)
[2] D. Bartesaghi et al., Nat. Commun. 6, 7083 (2014)
[3] K. Vandewal et al., Nat. Mater.13, 63 (2014); S. Albrecht et al., Adv. Mater. 26, 2533 (2014)
[4] J. Kurpiers et al., Scientific Reports, in press; A. Paulke et al., Appl. Phys. Lett. 108, 113505 (2016)
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.