A powder XRD, solid state NMR and calorimetric study of the phase evolution in mechanochemically synthesized dual cation (Cs(CHNH))PbX lead halide perovskite systems.

Methylammonium (MA) lead halide perovskites (MAPbX) have been widely investigated for photovoltaic applications, with the addition of Cs improving structural and thermal stability. This study reports the complete A site miscibility of Cs and MA cations in the lead chloride and lead bromide perovskites with nominal stoichiometric formulae (CsMA)Pb(Cl/Br) ( = 0, 0.13, 0.

Composition-tuned MAPbBr nanoparticles with addition of Cs cations for improved photoluminescence.

Hybrid organic-inorganic lead halide perovskite nanoparticles are promising candidates for optoelectronic applications. This investigation describes the structural and optical properties of MA Cs PbBr mixed cation colloidal nanoparticles spanning the complete compositional range of Cs substitution. A monotonic progression in the cubic lattice parameter () with changes in the Cs content confirmed the formation of mixed cation materials.

Heavy Water Additive in Formamidinium: A Novel Approach to Enhance Perovskite Solar Cell Efficiency.

Heavy water or deuterium oxide (D O) comprises deuterium, a hydrogen isotope twice the mass of hydrogen. Contrary to the disadvantages of deuterated perovskites, such as shorter recombination lifetimes and lower/invariant efficiencies, the serendipitous effect of D O as a beneficial solvent additive for enhancing the power conversion efficiency (PCE) of triple-A cation (cesium (Cs)/methylammonium (MA)/formaminidium (FA)) perovskite solar cells from ≈19.2% (reference) to 20.

Benzyl Alcohol-Treated CHNHPbBr Nanocrystals Exhibiting High Luminescence, Stability, and Ultralow Amplified Spontaneous Emission Thresholds.

We report the high yield synthesis of about 11 nm sized CHNHPbBr nanocrystals with near-unity photoluminescence quantum yield. The nanocrystals are formed in the presence of surface-binding ligands through their direct precipitation in a benzyl alcohol/toluene phase. The benzyl alcohol plays a pivotal role in steering the surface ligands binding motifs on the NC surface, resulting in enhanced surface-trap passivation and near-unity PLQY values.

Effect of Formamidinium/Cesium Substitution and PbI on the Long-Term Stability of Triple-Cation Perovskites.

Altering cation and anion ratios in perovskites has proven an excellent means of tuning the perovskite properties and enhancing the performance. Recently, methylammonium/formamidinium/cesium triple-cation mixed-halide perovskites have demonstrated efficiencies up to 22 %. Similar to the widely explored methylammonium lead halide, excess PbI is added to these perovskite films to enhance their performances.