The Effect of Lithium Doping in Solution-Processed Nickel Oxide Films for Perovskite Solar Cells

The effect of substitutional Li doping into NiO_x hole transporting layer (HTL) for use in inverted perovskite solar cells was systematically studied. Li doped NiO_x thin films with preferential crystal growth along the (111) plane were deposited using a simple solution-based process. Mott-Schottky analysis showed that hole carrier concentration (N_A) is doubled by Li doping. Utilizing 4 % Li in NiO_x improved the power conversion efficiency (PCE) of solar devices from 9.0 % to 12.6 %. Photoluminescence quenching investigations demonstrate better hole capturing properties of Li:NiO_x compared to that of NiO_x, leading to higher current densities by Li doping. The electrical conductivity of NiO_x is improved by Li doping. Further improvements of the device were made by using an additional ZnO layer onto PCBM, to remove shunt paths, leading to a PCE of 14.2 % and a fill factor of 0.72.     

Synthesis of (±)-cyclic dehypoxanthine futalosine, the biosynthetic intermediate in an alternative biosynthetic pathway for menaquinones

The first synthesis of (±)-cyclic dehypoxanthine futalosine (cyclic DHFL), a biosynthetic intermediate in the futalosine pathway for menaquinones operating in microorganisms, has been achieved. Efficient growth of the Streptomyces coelicolor mutant, which lacks the cyclic DHFL synthetase gene (mqnC gene) was observed in the presence of synthetic (±)-cyclic DHFL.