Publication date: 22nd July 2026
Two-dimensional (2D) Ruddlesden–Popper metal halide perovskites exhibit one of the most intriguing optical responses among layered semiconductors. Their spectra frequently display multiple sidebands, broad quasi-plateaus, and pronounced thickness-dependent features that challenge straightforward excitonic interpretations. Here, we critically reassess the optical response of 2D perovskites by examining the intertwined roles of electronic structure, exciton fine structure, exciton–phonon coupling, and photonic effects. We show that the exceptionally large excitonic oscillator strength and high refractive index of these materials naturally give rise to polaritonic stop bands and interference phenomena that can dominate reflection, transmission, and absorption spectra, even in nominally freestanding crystals. These photonic contributions, often overlooked, substantially reshape spectral line shapes and complicate the identification of distinct excitonic resonances, calling for a more integrated electronic–photonic framework for interpreting the optical response of two-dimensional perovskites.
In the second part of my talk, I will revisit the lattice dynamics of 2D layered perovskites and show that Raman active modes, involve substantial motion of the organic sublattice. This finding challenges the conventional assignment of low-frequency modes to predominantly inorganic framework motion and instead reveals their intrinsically hybrid organic–inorganic character. Moreover, these modes can be selectively engineered through chemical substitution of the organic spacer, establishing an additional degree of freedom for controlling lattice dynamics in 2D perovskites. We next probe the lattice response under electronic excitation and identify signatures consistent with polaron formation. These polarons are hybrid in nature: their stabilization requires the coupled response of both organic and inorganic sublattices. Such coupling provides a route to tune the polaronic state through hybrid phonon modes. This hybrid polarons shape the linear optical response of layered 2D perovskites
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.