Highly efficient tin-based perovskite solar cells are prepared by introducing the formamidinium thiocyanate additive into quasi-two-dimensional tin-based perovskites.

The development of bright fluorescent proteins (FPs) emitting beyond 600 nm continues to be of interest both from a fundamental perspective in understanding protein-chromophore interactions and from a practical perspective as these FPs would be valuable for cellular imaging. We previously reported ultrafast spectral observations of the excited-state dynamics in mPlum resulting from interconversion between direct hydrogen bonding and water-mediated hydrogen bonding between the chromophore acylimine carbonyl and the Glu16 side chain. Here, we report temperature-dependent steady-state and time-resolved fluorescence measurements of mPlum and its E16H variant, which does not contain a side-chain permitting hydrogen bonding with the acylimine carbonyl. Lowering the temperature of the system freezes interconversion between the hydrogen-bonding states, thus revealing the spectral signatures of the two states. Analysis of the temperature-dependent spectra assuming Boltzmann populations of the two states yields a 205 cm–1 energy difference. This value agrees with the predictions from a quantum mechanics/molecular mechanics study of mPlum (198 cm–1). This study demonstrates the first use of cryogenic spectroscopy to quantify the energetics and timescales of FP chromophore structural states that were only previously obtained from computational methods and further confirms the importance of acylimine hydrogen-bonding dynamics to the fluorescence spectral shifts of red FPs.

The need for cutting-edge solar power generation has led to the rapid development of organic–inorganic hybrid perovskites with unique photophysical properties. Photoinduced band-filling by free charge carriers, which is a consequence of the dynamic filling of the densities of states, modulates the optical transition toward high energy. Here, we observe strong band-filling in FA0.5MA0.5­Pb0.5­Sn0.5I3 polycrystalline films under continuous-wave excitation, which is much more evident than that in typical MAPbI3. Inspired by this fact, we propose novel electronic barrier adaptive concentrator-type photovoltaics, achieved by inserting an electronic barrier-inducing indene-C60 bisadduct layer (ICBA). Under concentrated illumination, the potential barrier between FA0.5MA0.5­Pb0.5­Sn0.5I3 and ICBA remarkably decreases, leading to a greater fill factor and a higher power conversion efficiency of 17.0% compared to that (15.6%) of the reference device. Our results provide a proof-of-concept demonstration of a novel photovoltaic system using the photophysical property of perovskites.

Symmetry-breaking charge transfer reaction of 9,9’-bianthracene is driven exclusively by the rotational fluctuation of solvents, not including the inertial component in the solvation dynamics. Torsional motion and bond shortening during the reaction were observed.