Phosphine Oxide Derivative as a Passivating Agent to Enhance the Performance of Perovskite Solar Cells

Defects of metal-halide perovskites detrimentally influence the optoelectronic properties of the thin film and, ultimately, the photovoltaic performance of perovskite solar cells (PSCs). Especially, defect-mediated nonradiative recombination that occurs at the perovskite interface significantly limits the power conversion efficiency (PCE) of PSCs. In this regard, interfacial engineering or surface treatment of perovskites has become a viable strategy for reducing the density of surface defects, thereby improving the PCE of PSCs. Here, an organic molecule, tris(5-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)phosphine oxide (THPPO), is synthesized and introduced as a defect passivation agent in PSCs. The P=O terminal group of THPPO, a Lewis base, can passivate perovskite surface defects such as undercoordinated Pb2+. Consequently, improvement of PCEs from 19.87 to 20.70% and from 5.84 to 13.31% are achieved in n−i−p PSCs and hole-transporting layer (HTL)-free PSCs, respectively

Strategies for Tuning Emission Energy in Phosphorescent Ir(III) Complexes

. Research into phosphorescent Ir(III) complexes has grown immensely since their first report. Talented chemists have successfully synthesized complexes capable of emitting from the UV to the near-IR regions of the electromagnetic spectrum. Tuning the emission energy in a selective manner requires knowledge of how ligand substitution affects not only energy levels such as the HOMO and LUMO, but also the emissive triplet energy level. This review describes fundamental principles involved in energy-level engineering and substituent selection as well as fundamental methods of device c..

An Efficient Synthesis of Bis-1,3-(3′-aryl‑<i>N</i>‑heterocycl-1′-yl)arenes as CCC-NHC Pincer Ligand Precursors

A report that demonstrated an efficient methodology for the arylation of imidazoles has been extended to bis­(<i>N</i>-heterocyclic) compounds. Using bis­(aryl) iodonium salts provides high-yielding access to CCC-NHC ligand precursors in a single step. Examples of arylation using various iodonium salts are reported herein with an investigation into the factors governing their relative rate of reactivity. The metalation of one of these compounds using Zr­(NMe₂)₄ and its subsequent treatment with [Pt­(COD)­Cl₂] to yield a transmetalated product are reported

Homobimetallic Rhodium NHC Complexes as Versatile Catalysts for Hydrosilylation of a Multitude of Substrates in the Presence of Ambient Air

Two recently reported air- and water-stable di-Rh complexes based on 1,3-bis­(3′-butylbenzimidazol-2′-ylidene)­benzene were utilized as catalysts for hydrosilylation. Among the substrates investigated were aldehydes, ketones, α,β-unsaturated carbonyls, acyl chlorides, nitriles, alkenes, nitro groups, isocyanates, and tertiary amides. Additionally, carbon dioxide underwent hydrosilylation to produce dimethylphenylsilylformate. The catalysts compared well to other previously reported hydrosilylation catalysts, and the Rh–Cl catalyst was found to be faster and more selective than the Rh–I complex in each case

Photocatalytic Reduction of CO₂ with Re-Pyridyl-NHCs

A series of Re­(I) pyridyl N-heterocyclic carbene (NHC) complexes have been synthesized and examined in the photocatalytic reduction of CO₂ using a simulated solar spectrum. The catalysts were characterized through NMR, UV–vis, cyclic voltammetry under nitrogen, and cyclic voltammetry under carbon dioxide. The complexes were compared directly with a known benchmark catalyst, Re­(bpy) (CO)₃Br. An electron-deficient NHC substituent (PhCF₃) was found to promote catalytic activity when compared with electron-neutral and -rich substituents. Re­(PyNHC-PhCF₃) (CO)₃Br was found to exceed the CO production of the benchmark Re­(bpy) (CO)₃Br catalyst (51 vs 33 TON) in the presence of electron donor <b>BIH</b> and photosensitizer <i>fac</i>-Ir­(ppy)₃. Importantly, Re­(PyNHC-PhCF₃) (CO)₃Br was found to function without a photosensitizer (32 TON) at substantially higher turnovers than the benchmark catalyst Re­(bpy) (CO)₃Br (14 TON) under a solar simulated spectrum

A low recombination rate indolizine sensitizer for dye-sensitized solar cells

A sensitizer incorporating a heavily alkylated surface blocking indolizine donor exhibits excellent light absorption and diminished recombination rates in dye-sensitized solar cells (DSCs). DSC device efficiencies (up to 8%) using either I-/I-3(-) or Co(bpy)(3)(2+/3+) redox shuttles were obtained, which compare favourably to the known excellent surface coverage co-sensitization dye, D35

Synthesis and Characterization of a 1,3-Phenylene-Bridged N‑Alkyl Bis(benzimidazole) CCC-NHC Pincer Ligand Precursor: Homobimetallic Silver and Rhodium Complexes and the Catalytic Hydrosilylation of Phenylacetylene

A new CCC-NHC pincer ligand precursor architecture based on 1,3-bis­(N-alkylbenzimidazole)­benzene has been synthesized and metalated using Ag₂O, forming a homobimetallic Ag complex with a metal to ligand ratio of 1:1. The Ag complex was treated with either [Rh­(COD)­Cl]₂ or Rh­(COD)₂OTf and NBu₄I to yield a homobimetallic Rh complex by transmetalation. The Rh complexes were characterized, and an X-ray structure is reported. Their catalytic activity in the hydrosilylation of phenylacetylene is reported