This study evaluated the inactivation of SARS-CoV-2, the virus responsible for COVID-19, by ozone using virus grown in cell culture media either dried on surfaces (plastic, glass, stainless steel, copper, and coupons of ambulance seat and floor) or suspended in liquid. Treatment in liquid reduced SARS-CoV-2 at a rate of 0.92±0.11 log 10 -reduction per ozone CT dose(mg.min/L); where CT is ozone concentration times exposure time. On surface, the synergistic effect of CT and relative humidity (RH) was key to virus inactivation; the rate varied from 0.01 to 0.27 log 10 -reduction per ozone CT value(g.min/m 3 ) as RH varied from 17% to 70%. Depletion of ozone by competitive reactions with the medium constituents, mass transfer limiting the penetration of ozone to the bulk of the medium, and occlusion of the virus in dried matrix were postulated as potential mechanisms that reduce ozone efficacy. RH70% was found plausible since it provided the highest disinfection rate while being below the critical RH that promotes mould growth in buildings. In conclusion, through careful choice of (CT, RH), gaseous ozone is effective against SARS-CoV-2 and our results are of significance to a growing field where ozone is applied to control the spread of COVID-19.

A mathematical model was developed to estimate the number of logarithmic cycles (LDec) of lipopolysaccharide concentration destroyed by a dry-heat sterilization process. The LDec values calculated from the mathematical model agreed well with those obtained from the destruction of lipopolysaccharide by a dry-heat treatment. A discussion of how the mathematical model may be used to evaluate a dry-heat sterilization cycle is presented. This mathematical model and the dryheat destruction curves indicated existence of a maximum LDec value at each temperature. The implications of this finding are discussed.

Properties of the electron transport layer (ETL) are known to influence the performance of lead halide perovskite solar cells (PSCs). But so far very little emphasis has been given on the increased impact of this layer at low light. In this work we compare the effect of thickness and coverage of a TiO2 compact layer on the performance and hysteresis of standard methyl ammonium lead iodide planar devices tested under 200 lux vs. 1 sun illumination. Standard TiO2 layers are produced with incremental thickness and coverage by application of spray pyrolysis of a Ti-acetylacetonate precursor (0-50 sprays, 1 spray ~ 1 nm TiO2). Thorough materials characterisation combining FEG-SEM, XPS, and cyclic voltammetry shows that a crystalline, nearly pin-hole free TiO2 layer is achieved by sequential deposition of ≥ 15 sprays over small to large areas (0.2 mm 2-1 cm 2). Device performance is affected by two main parameters, namely the coverage yield and thickness of the TiO2 layer, especially under 200 lux illumination. A 25 vs. 50 sprays-TiO2 layer is found to provide the best compromise between coverage and thickness to avoid charge recombination at the TiO2/perovskite interface whilst minimizing resistive losses with 11.7 % average PCE at 200 lux vs 7.8 % under 1 sun. Finally, the analysis of I/V forward vs. reverse scans and open circuit voltage decay data suggests that hysteresis is greatly affected by the capacitive properties of the ETL at low light, whilst other phenomena such as ion migrations may dominate under 1 sun.

A commercially available glass substrate which incorporates both a fluorine‐doped tin oxide and compact TiO2 layer deposited through chemical vapor deposition that is commonly used in “solar control products,” is presented. The substrate, known commercially as Pilkington Eclipse Advantage, is designed for use as an infrared radiation control product and this is the first known instance of it being employed and extensively characterized for use as a mass manufactured n‐type contact in perovskite solar cells. Using this substrate with no additional compact TiO2 layer, perovskite solar cells with PCEs of up to 15.9% are achieved. These devices are superior in performance to those where the compact TiO2 is deposited via spray pyrolysis. The reproducibility and large scale manufacturing base already established with this substrate represents significant potential for solving the problem of upscaling a uniform and pinhole free n‐type compact TiO2 blocking layer.

Solution processing of TiO 2 compact layers for 3 rd generation p h o t o v o l t a i c s , Ceramics International,