Correlating phase behavior with photophysical properties in mixed‐cation mixed‐halide perovskite thin films

Mixed cation perovskites currently achieve very promising efficiency and operational stability when used as the active semiconductor in thin‐film photovoltaic devices. However, an in‐depth understanding of the structural and photophysical properties that drive this enhanced performance is still lacking. Here the prototypical mixed‐cation mixed‐halide perovskite (FAPbI3)0.85(MAPbBr3)0.15 is explored, and temperature‐dependent X‐ray diffraction measurements that are correlated with steady state and time‐resolved photoluminescence data are presented. The measurements indicate that this material adopts a pseudocubic perovskite α phase at room temperature, with a transition to a pseudotetragonal β phase occurring at ≈260 K. It is found that the temperature dependence of the radiative recombination rates correlates with temperature‐dependent changes in the structural configuration, and observed phase transitions also mark changes in the gradient of the optical bandgap. The work illustrates that temperature‐dependent changes in the perovskite crystal structure alter the charge carrier recombination processes and photoluminescence properties within such hybrid organic–inorganic materials. The findings have significant implications for photovoltaic performance at different operating temperatures, as well as providing new insight on the effect of alloying cations and halides on the phase behavior of hybrid perovskite materials

Synthesis and characterisation of pentacarbonyl(thiazolyl)manganese(0) complexes and their conversion to cationic 2,3-dihydro-thiazol-2-ylidene(pentacarbonyl)manganese(0) compounds

Treatment of BrMn(CO)5 with the corresponding thiazolyllithium precursor produced [(CO)5Mn{C=NCH= CH3}] (1) or [(CO)5Mn{C=N(CH3)=CHS}] (2). Protonation or alkylation of 1 or 2 yields [(CO)5Mn{CN(H)CH=CHS}][CF3SO3] (3), [(CO)5- Mn{CN(H)C(CH3)=CHS}][CF3SO3] (4), [(CO)5Mn{CN(CH3)CH=CHS}][CF3SO3] (5) or [(CO)5Mn{CN(CH3)C(CH3)=CHS}] [CF3SO3] (6). The relatively long Mn-C(carbene) bond in the molecular structures of 3 [2.010(12) Å] and 4 [2.044(3) Å] and structural features of the 2,3-dihydro-thiazol-2-ylidene ligand, attest to stabilisation of the carbene ligand by π-bonding from the N atom and little π-acceptance by the ligand from the metal. © 2001 Elsevier Science Ltd. All rights reserved.Articl