Vapour-Deposited Cesium Lead Iodide Perovskites: Microsecond Charge Carrier Lifetimes and Enhanced Photovoltaic Performance.

Metal halide perovskites such as methylammonium lead iodide (MAPbI3) are highly promising materials for photovoltaics. However, the relationship between the organic nature of the cation and the optoelectronic quality remains debated. In this work, we investigate the optoelectronic properties of fully inorganic vapour-deposited and spin-coated black-phase CsPbI3 thin films. Using the time-resolved microwave conductivity technique, we measure charge carrier mobilities up to 25 cm2/(V s) and impressively long charge carrier lifetimes exceeding 10 μs for vapour-deposited CsPbI3, while the carrier lifetime reaches less than 0.2 μs in the spin-coated samples. Finally, we show that these improved lifetimes result in enhanced device performance with power conversion efficiencies close to 9%. Altogether, these results suggest that the charge carrier mobility and recombination lifetime are mainly dictated by the inorganic framework rather than the organic nature of the cation

Treatment of household greywater laden with household chemical products in a multi-chambered anaerobic biofilm reactor

Anaerobic treatment of greywater (GW) is challenging due to the presence of recalcitrant household chemical products (HCP) that inhibit the activity and growth of organic pollutant degrading anaerobic microbes. This research attempted to overcome this challenge through a novel, mull-chambered anaerobic biofilm reactor (AnBR) containing fluidized PVC media and packed bed lignocellulosic fiber (Cows nucifera) as biofilm support. The long-term effects of feeding HCP laden GW and effluent recycling on the performance of AnBR were corroborated with the bioconversion data and microbial community dynamics. The results indicated that the composition of wastewater and recycling both determine the rates of COD removal, microbial population, and diversity in AnBR. The inhibitory effects exhibited by GW constituents reduced the COD removal efficiencies by 74-94% in comparison to standard substrates (SS), while simultaneously reducing microbial population and diversity by 30-40%. Effluent recycling in GW and SS fed AnBR enhanced the rates of COD removal from 160 mg/L.day to 214 mg/L.day, and 627 mg/L.day to 3540 mg/L.day respectively, with the selective enrichment of Proteobacteria sp. and Methanogenic sp. The GW fed AnBR was dominated by aromatics degrading species of alpha-Proteobacteria, Synergistetes, etc., whereas, SS fed AnBR were inhabited by fermentative species of delta-Proteobacteria, Bacteroidetes, etc

Development of a Perovskite Solar Cell Architecture for Opaque Substrates

To date, substrate-configuration metal-halide perovskite solar cells (PSCs) fabricated on opaque substrates such as metal foils provide inferior efficiencies compared with superstrate-configuration cells on transparent substrates such as glass. Herein, a substrate-configuration PSC on planarized steel is presented. To quantify the differences between the two configurations, a 15.6%-efficient n–i–p superstrate-configuration PSC is transformed step wise into a substrate-configuration cell. Guided by optical modeling, the opaque Au electrode is replaced by a transparent MoO3/thin Au/polystyrene dielectric–metal–dielectric electrode. The semitransparent device affords efficiencies of 15.4% and 11.4% for bottom and top illumination, respectively. Subsequently, substrate-configuration PSCs with a metal bottom electrode are fabricated on glass and planarized steel, using a thin MoO3 interlayer between the Au bottom electrode and the SnO2 electron transport layer. The glass-based substrate-configuration cell provides 14.0% efficiency with identical open-circuit voltage and fill factor as the superstrate cell. The cell on planarized steel reaches 11.5% efficiency due to a lower fill factor. For both substrate-configuration cells, the lower short-circuit current density limits the efficiency. Optical modeling explains this quantitatively to be due to absorption and reflection by the top electrode and absorption by the organic hole transport layer