Semiconducting molecules have been employed to passivate traps extant in the perovskite film for enhancement of perovskite solar cells (PSCs) efficiency and stability. A molecular design strategy to passivate the defects both on the surface and interior of the CH3NH3PbI3 perovskite layer, using two phthalocyanine (Pc) molecules (NP‐SC6‐ZnPc and NP‐SC6‐TiOPc) is demonstrated. The presence of lone electron pairs on S, N, and O atoms of the Pc molecular structures provides the opportunity for Lewis acid–base interactions with under‐coordinated Pb2+ sites, leading to efficient defect passivation of the perovskite layer. The tendency of both NP‐SC6‐ZnPc and NP‐SC6‐TiOPc to relax on the PbI2 terminated surface of the perovskite layer is also studied using density functional theory (DFT) calculations. The morphology of the perovskite layer is improved due to employing the Pc passivation strategy, resulting in high‐quality thin films with a dense and compact structure and lower surface roughness. Using NP‐SC6‐ZnPc and NP‐SC6‐TiOPc as passivating agents, it is observed considerably enhanced power conversion efficiencies (PCEs), from 17.67% for the PSCs based on the pristine perovskite film to 19.39% for NP‐SC6‐TiOPc passivated devices. Moreover, PSCs fabricated based on the Pc passivation method present a remarkable stability under conditions of high moisture and temperature levels.

Although bis­(diarylamino) mixed-valence radical cations have been quite extensively studied, their bis­(carbazolyl) analogues have not, even though the hole-transporting properties of species such as of 4,4′-bis­(9H-carbazol-9-yl)-1,1′-biphenyl, CBP, are widely exploited in organic light-emitting diodes. This work reports the generation by chemical oxidation of the radical cations of 4,4′-bis­(3,6-di-tert-butyl-9H-carbazol-9-yl)-1,1′-biphenyl (a model for the unstable radical cation of CBP), 2,7-bis­(3,6-di-tert-butyl-9H-carbazol-9-yl)-4,5,9,10-tetrahydropyrene, and 2,7-bis­(3,6-di-tert-butyl-9H-carbazol-9-yl)­pyrene. The visible and near-IR spectra of these cations have been compared to those of the corresponding dication spectra, to the spectrum of the 3,6-di-tert-butyl-9-(4-(tert-butyl)­phenyl)-9H-carbazole radical cation, and to the results of time-dependent density-functional calculations. The biphenyl- and pyrene-bridged species are found to be localized (class-II) mixed-valence compounds, whereas stronger coupling between the redox centers in the tetrahydropyrene-bridged radical cation results in a delocalized (class-III) species. For all three radical cations, the electronic couplings are lower than those obtained for delocalized 4,4′-bis­(diarylamino)-1,1′-biphenyl radical cations.

Nine 1,3,6,8-tetraarylpyrenes were prepared and characterized for OLED-based blue-light emission.

Dioxiranes are multi-tasking reagents inheriting mild and selective oxygen transfer attributes. These oxidants are accessed from the reaction of ketones with an oxidant and are employed stoichiometrically or catalytically (in...

A new metal-free ortho oxidation of 2,7-di-tert-butylpyrene provides in high yield the corresponding 4,5-dione and 4,5,9,10-tetraone in environmentally benign solvents.