Degradation of Perovskite Thin Films and Solar Cells with Candle Soot C/Ag Electrode Exposed in a Control Ambient

Perovskite solar cells (PSCs) have already achieved efficiencies of over 25%; however, their instability and degradation in the operational environment have prevented them from becoming commercially viable. Understanding the degradation mechanism, as well as improving the fabrication technique for achieving high-quality perovskite films, is crucial to overcoming these shortcomings. In this study, we investigated details in the changes of physical properties associated with the degradation and/or decomposition of perovskite films and solar cells using XRD, FESEM, EDX, UV-Vis, Hall-effect, and current-voltage (I-V) measurement techniques. The dissociation, as well as the intensity of perovskite peaks, have been observed as an impact of film degradation by humidity. The decomposition rate of perovskite film has been estimated from the structural and optical changes. The performance degradation of novel planner structure PSCs has been investigated in detail. The PSCs were fabricated in-room ambient using candle soot carbon and screen-printed Ag electrode. It was found that until the perovskite film decomposed by 30%, the film properties and cell efficiency remained stable.

Optimization Study of Adsorption Parameter for Removal of Dye Pollutant Using Candle Soot Coated Egg Carton

In this study, several parameters that affect the adsorption capacity of Rhodamine B (RhB) dyes were reviewed which include initial pH, temperature, contact time and initial dye concentration. Experimental data was extracted from other literatures as input for subsequent optimization study. Design Expert version 11.1.2.0 software was used to find the optimal condition for adsorption of RhB dyes from wastewater by using candle soot coated on egg carton (CS-Egg) as absorbent. The Central Composite Design (CCD) in response surface methodology (RSM) was employed to perform the optimization and analysis process as it was effective in determining the optimal condition for the adsorption process. CCD evaluated many parameters at the same time and thus reducing the number of experiments required. The optimum condition to maximize the adsorption efficiency was obtained at pH 7, 262.5 mg/L, 60 min of contact time and 55 °C. The highest predicted adsorption efficiency of RhB dye was 90 % at optimum condition. The optimization of parameter provides a better understanding on the adsorption efficiency before conducting the actual experimental work.

Efficient Oil-Water Separation Coating With Robust Superhydrophobicity and High Transparency

There has been a growing interest in oil-water separation due to the massive economic and energy loss caused by world-wide oil spill. In the past decades, a new type of superhydrophobic surface has been developed for the efficient oil-water separation, but its large-scale use is significantly limited by its expensive, sophisticated, and fragile roughness structure. Meanwhile, to handle complex operating conditions, the transparency of the superhydrophobic surface has been more attractive due to its potential visual oil-water separation and optical applications. Herein, we showed a simple and versatile strategy to fabricate superhydrophobic coating with robustness and high transparency. Subsequently, this multifunctional superhydrophobic coating was utilized for oil-water separation and indicated excellent separation efficiency. In this strategy, candle soot composed of carbon nanoparticles was deposited onto the substrate and used as a rough surface template. Then, a filmy and hard silica shell was modified onto this template via chemical vapor deposition to reinforce the roughness structure. Following, this soot-silica coated substrate was calcined in air to remove the candle soot template. Finally, based on a rational surface design, this robust silica coating achieved excellent superhydrophobicity thereby showing inherently oil-water separation benefits. This reinforced superhydrophobic coating presented robust superhydrophobicity even after 410 s sand impacting with the height of 40 cm. Also, it retained excellent oil-water separation efficiency even after reuses.