Improving Thermal Stability of High-Efficiency Methylammonium-Free Perovskite Solar Cells via Chloride Additive Engineering.

Tin dioxide (SnO2), in perovskite solar cells (PSCs), stands out as the material most suited to the electron transport layer (ETL), yielding advantages with regard to ease of preparation, high mobility, and favorable energy level alignment. Nonetheless, there is a chance that energy losses from defects in the SnO2 and interface will result in a reduction in the Voc. Consequently, optimizing the interfaces within solar cell devices is a key to augmenting both the efficiency and the stability of PSCs. Herein this present study, we introduced butylammonium chloride (BACl) into the SnO2 ETL. The resulting optimized SnO2 film mitigated interface defect density, thereby improving charge extraction. The robust bonding capability of negatively charged Cl- ions facilitated their binding with noncoordinated Sn4+ ions, effectively passivating defects associated with oxygen vacancies and enhancing charge transport within the SnO2 ETL. Concurrently, doped BA+ and Cl- diffused into the perovskite lattice, fostering perovskite grain growth and reducing the defects in perovskite. In comparison to the control device, the Voc saw a 70 mV increase, achieving a champion efficiency of 22.86%. Additionally, following 1000 h of ambient storage, the unencapsulated device based on SnO2 preburied with BACl retained around 90% of its initial photovoltaic conversion efficiency.

A new mono-functionalized organoimido hexa-molybdate derivative: bis-(tetra-n-butyl-ammonium) (5-chloro-2-methyl-phenyl-imido)-µ(6)-oxido-dodeca-µ(2)-oxido-penta-oxidohexa-molybdate(VI).

The title complex, [(C(4)H(9))(4)N](2)[Mo(6)(C(7)H(6)ClN)O(18)], was prepared by the reaction of (Bu(4)N)(4)[α-Mo(8)O(26)] and 2-methyl-5-chloro-aniline hydro-chloride with N,N'-dicyclo-hexyl-carbodiimide as dehydrating agent in dry acetonitrile solution. The aryl-imido ligand is linked to an Mo atom of the Lindqvist-type hexamolybdate anion by an Mo N triple bond, with a bond length of 1.732 (4) Šand an Mo N-C bond angle of 169.1 (4)°, typical for monodentate imido groups in such hybrid complexes. Due to the inter-action between one H atom in the aryl group and an O atom of a symmetry-related hexa-molybdate cluster, the anions form centrosymmetric dimers in the crystal structure. Weak C-H⋯O contacts are observed between the cations and anions. Unresolved disorder in some of the butyl chains of the ammonium cation is noted.