MXenes, a newly intriguing family of 2D materials, have recently attracted considerable attention owing to their excellent properties such as high electrical conductivity and mobility, tunable structure, and termination groups. Here, the Ti3C2Tx MXene is incorporated into the perovskite absorber layer for the first time, which aims for efficiency enhancement. Results show that the termination groups of Ti3C2Tx can retard the crystallization rate, thereby increasing the crystal size of CH3NH3PbI3. It is found that the high electrical conductivity and mobility of MXene can accelerate the charge transfer. After optimizing the key parameters, 12% enhancement in device performance is achieved by 0.03 wt% amount of MXene additive. This work unlocks opportunities for the use of MXene as potential materials in perovskite solar cell applications.

For the first time, a new lead-free double perovskite Cs2NaBiI6 material was synthesized and applied to the perovskite solar cells.

All-inorganic perovskites are attracting increasing attention due to their superior thermal stability than that of the traditional CH 3 NH 3 PbI 3 , while their inferior phase stability in ambient conditions is still an unsolved issue. Here, for the first time, we report the incorporation of niobium (Nb 5+ ) ions into the CsPbI 2 Br perovskite. Results indicate that Nb 5+ can effectively stabilize the photoactive α-CsPbI 2 Br phase by the possible substitution of Pb 2+ . With 0.5% Nb doping, the carbon electrode-based all-inorganic perovskite solar cells achieved a high photoconversion efficiency value of 10.42%, 15% higher than that of the control device. The Nb 5+ incorporation reduces the charge recombination in the perovskite, leading to a champion V oc value of 1.27 V and a negligible hysteresis effect. This work explicates the high compatibility of all-inorganic perovskite materials and unlocks the opportunities for the use of high-valence ions for perovskite property modification.

The Voc of carbon based CsPbIBr2 PSCs can be highly boosted through the surface passivation of SnO2 films.

For the rapid growth of population electrical and electronics equipment waste are generated 20 to 50 million tones in world-wide. Half a tonne of e-waste creates by the resident of advanced country in every year. E-waste contains different toxic substances including metals, plastics and refractory oxides which are hazardous or risky for our environment and human wellbeing, thus e-waste management is an essential. Hence, this review outlined the global status of e-waste and its current progress on management worldwide. An exhaustive survey of literature was made on the latest technological approaches in noble and base metals recovery from waste printed circuit boards (PCBs) of electrical and electronic equipment. An emphasis was given to review the most important features of existing industrial routes associated with the metal recovery systems from PCBs. The discussions of green technologies as alternatives of conventional approaches to obtain precious metals from e-waste were overviewed. The application of microbial bioleaching approaches in the extraction metals from e-waste was highlighted. Finally, the concern for the challenges and barriers associated with the e-waste management process in Bangladesh was outlined.

Global energy crisis are as a result of gradual depletion of fossil fuel reserves, coupled with population growth in developing countries. Besides, fossil fuels are not environmentally benign as they are associated with problems, i.e. global warming, high toxicity and non biodegradability, hence it is considered as non sustainable source of energy. Without doubt, biofuel-based energy is a promising long-term energy source that can reduce the over dependence on fossil fuels as a result of feedstocks availability and renewability. However, biodiesel production from vegetable oil using the traditional homogeneous catalytic system is no longer defensible by industries in the near future, particularly due to food-fuel rivalry and ecological problems related to the conventional homogeneous catalytic system. This review presents a comprehensive step by step process of converting waste cooking oil (WCO) to biodiesel, using modified waste egg shell catalyst. The modified waste egg shell derived bifunctional catalyst could easily be removed from the fatty acid methyl esters (FAME) with limited environmental effects. The new modified catalytic system is able to convert the high free fatty acid (FFA) content waste cooking oil to FAME efficiently under moderate reaction conditions. Utilization of waste cooking oil as a feedstock for biodiesel production will reduce the food security issues that stem the biodiesel production from food-grade oil. Moreover, it will reduce the total production cost of the FAME due to its low cost. The major objective of this article is to demonstrate the current state of the use of heterogeneous bifunctional acid/base catalyst to produce biodiesel from green and nonedible waste cooking oil. At the end of the article, perspectives and future developments are also presented.

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Perovskite solar cells based on series of inorganic cesium lead bromide and iodide mixture, CsPbBr3-xIx, where x varies between 0, 0.1, 0.2, and 0.3 molar ratio were synthesized by two step-sequential deposition at ambient condition to design the variations of wide band gap light absorbers. A device with high overall photoconversion efficiency of 3.98 % was obtained when small amount of iodide (CsPbBr2.9I0.1) was used as the perovskite and spiro-OMeTAD as the hole transport material (HTM). We investigated the origin of variation in open circuit voltage, Voc which was shown to be mainly dependent on two factors, which are the band gap of the perovskite and the work function of the HTM. An increment in Voc was observed for the device with larger perovskite band gap, while keeping the electron and hole extraction contacts the same. Besides, the usage of bilayer P3HT/MoO3 with deeper HOMO level as HTM instead of spiro-OMeTAD, thus increased the Voc from 1.16 V to 1.3 V for CsPbBr3 solar cell, although the photocurrent is lowered due to charge extraction issues. The stability studies confirmed that the addition of small amount of iodide into the CsPbBr3 is necessarily to stabilize the cell performance over time.