Ultrafast Triplet Generation at the Lead Halide Perovskite/Rubrene Interface

Triplet sensitization of rubrene by bulk lead halide perovskites has recently resulted in efficient infrared-to-visible photon upconversion via triplet-triplet annihilation. Notably, this process occurrs under solar relavant fluxes, potentially paving the way toward integration with photovoltaic devices. In order to further improve the upconversion efficiency, the fundamental photophysical pathways at the perovskite/rubrene interface must be clearly understood to maximize charge extraction. Here, we utilize ultrafast transient absorption spectroscopy to elucidate the processes underlying the triplet generation at the perovskite/rubrene interface. Based on the bleach and photoinduced absorption features of the perovskite and perovskite/rubrene devices obtained at multiple pump wavelengths and fluences, along with their resultant kinetics, our results do not support charge transfer states or long-lived trap states as the underlying mechanism. Instead, the data points towards a triplet sensitization mechanism based on rapid extraction of thermally excited carriers on the picosecond timescale.

Variation of Energy Density and Mass Density of Photon with Wavelength

The mass density and energy density of visible photon is calculated as and , respectively. Moreover it is also observed that mass density and energy density of photon depend upon photons mass, wavelength, volume and energy. This is clear from figure 1, figure 2 and literatures. Therefore the mass density and energy density of photon varies with masses of photon, wavelength, volume, etc.

Variation of Energy Density and Mass Density of Photon with Wavelength

The mass density and energy density of visible photon is calculated as 10-8 Kgm-3 and 109jm3 respectively. Moreover it is also observed that mass density and energy density of photon depend upon photons mass, wavelength, volume and energy. This is clear from figure 1, figure 2 and literatures. Therefore the mass density and energy density of photon varies with masses of photon, wavelength, volume, etc.

Non-linear interferometry with infrared metasurfaces

The optical elements comprised of sub-diffractive light scatterers, or metasurfaces, hold a promise to reduce the footprint and unfold new functionalities of optical devices. A particular interest is focused on metasurfaces for manipulation of phase and amplitude of light beams. Characterisation of metasurfaces can be performed using interferometry, which, however, may be cumbersome, specifically in the infrared (IR) range. Here, we realise a new method for characterising metasurfaces operating in the telecom IR range using accessible components for visible light. Correlated IR and visible photons are launched into a non-linear interferometer so that the phase profile, imposed by the metasurface on the IR photons, modifies the interference at the visible photon wavelength. Furthermore, we show that this concept can be used for broadband manipulation of the intensity profile of a visible beam using a single IR metasurface. Our method unfolds the potential of quantum interferometry for the characterization of advanced optical elements.

Hole-mediated photoredox catalysis: tris(p-substituted)biarylaminium radical cations as tunable, precomplexing and potent photooxidants

Triarylamines are demonstrated as novel, tunable electroactivated photocatalysts that use dispersion precomplexation to harness the full potential of the visible photon (>4.0 V vs. SCE) in anti-Kasha photo(electro)chemical super-oxidations of arenes.