Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV16)
Publication date: 28th March 2016
Among the variety of spectroscopic techniques employed to investigate hybrid halide perovskite materials, electron magnetic resonance (EPR) methods are not extensively applied so far[1]. However, EPR methods are often used to study paramagnetic species in semiconducting materials. In particular, the microscopic insight of EPR has been profitably applied to investigate point defects, intrinsic and extrinsic defects and photoinduced processes in oxide perovskites[2], in semiconducting polymers and in complex photoactive materials[3].
We undertook the task of investigating some organolead trihalide hybrid perovskites (MAPbX3; X=Br or I) and composite perovskite/organic semiconductor materials, using EPR spectroscopy, with the aim of identifying the presence of intrinsic paramagnetic defects, photogenerated paramagnetic species and charge formation and recombination processes, all involving unpaired spin species. Furthermore, we synthesized some extrinsically doped perovskite materials using paramagnetic metals, where the doping centre is used to probe the local environment and the paramagnetic species dynamics.
We observed a low level of intrinsic paramagnetic species both in single crystals and in microcrystalline powders. After photoexcitation of perovskite samples the formation of paramagnetic species is observed, although in very low yield. In composite perovskite/PCBM materials, a stronger photoinduced formation of charges, mainly observed as PCBM anion radicals, is detected, demonstrating a stabilization of separated charges in the mixed material.
In some chemically doped perovskite single crystals we observed a reversible quenching of paramagnetism induced by visible light absorption, a phenomenon attributed to trapping of charge carriers by the dopant species.
[1] I. A. Shkrob et al., J. Phys. Chem. Lett. 5, 1066–1071 (2014)
[2] Properties of Perovskites and Other Oxides, K. A. Müller and T. W. Kool, World Scientific Publishing, Singapore (2010)
[3] F. Kraffert, J. Phys. Chem. C, 118, 28482–28493 (2014)
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.