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⁻/I₃ ⁻ or Co(bpy)₃ ^2+/3+ redox shuttles were obtained, which compare favourably to the known excellent surface coverage co-sensitization dye, D35.

Re(pyNHC-PhCF₃)(CO)₃Br is a highly active photocatalyst for CO₂ reduction. The PhCF₃ derivative was previously empirically shown to be a robust catalyst. Here, the role of the PhCF₃ group is probed computationally and the robust nature of this catalyst is analyzed with regard to the presence of water and oxygen introduced in controlled amounts during the photocatalytic reduction of CO₂ to CO with visible light. This complex was found to work well from 0–1% water concentration reproducibly; however, trace amounts of water were required for benchmark Re(bpy)(CO)₃Cl to give reproducible reactivity. When ambient air is added to the reaction mixture, the NHC complex was found to retain substantial performance (~50% of optimized reactivity) at up to 40% ambient atmosphere and 60% CO₂ while the Re(bpy)(CO)₃Cl complex was found to give a dramatically reduced CO₂ reduction reactivity upon introduction of ambient atmosphere. Through the use of time-correlated single photon counting studies and prior electrochemical results, we reasoned that this enhanced catalyst resilience is due to a mechanistic difference between the NHC- and bpy-based catalysts. These results highlight an important feature of this NHC-ligated catalyst: substantially enhanced stability toward common reaction contaminates.