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Abstract The noticeable growth in the power conversion efficiency of solution-processed organo-inorganic halide perovskite solar cells (OIHPSCs) incited the photovoltaic community to look for limitations that hurdle the commercialization process. The surface and interface defects between the perovskite and electron transport layers are among the main challenges that cause significant non-radiative recombination losses, thereby they result in poor performance and stability. In this work, tetracyanoquinodimethane (TCNQ), a strong electron acceptor molecule, is applied at the interface between the photoactive perovskite and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) layers to modify the interface, and enhance device performance and stability. Steady-state and time-resolved photoluminescence measurements were used to characterize the role of the TCNQ passivation in reducing non-radiative recombination of charge carriers. Current density versus voltage (J-V) measurements show improvement in devices open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF) for devices with TCNQ interface passivation, which is attributed to suppressed non-radiative recombination. In addition, a noticeable improvement in the device’s stability was observed. This study reveals the dual role of TCNQ passivation in improving the photoelectric properties and stability of ambient air processed perovskite devices with the pin architecture.

Abstract The unprecedented increase in power conversion efficiency (PCE) of low‐cost organo‐inorganic halide perovskite solar cells (OIHPSCs) toward its Shockley‐Queisser limit intriguingly has prompted researchers to investigate the disadvantages of these devices. The issue of operational stability is the main hurdle challenging the way forward for commercialization. To address this, various engineering processes like composition, additives, anti‐solvents, bulk and interface passivation, and deposition techniques have been widely applied to manage both extrinsic and intrinsic factors that induce degradation of the OIHPSCs. In this work, we employed interface passivation, which is an efficient approach to reduce nonradiative recombination. An ultrathin layer of electron donor diketopyrrolopyrrole‐oligothiophene copolymer (DPP860) was applied as an interface passivator between the photoactive layer and [6,6]‐phenyl C61 butyric acid methyl ester (PCBM). The role of the interface passivation on optoelectronic properties of the OIHPSCs was assessed using current density versus voltage (J‐V) characteristics, photoluminescence spectroscopy and time‐resolved photoluminescence spectroscopy. The findings show devices treated with DPP860 exhibit enhanced current density (Jsc) and fill factor, attributing for suppressed nonradiative recombination. Moreover, it shows relative improvement in the stability of the device. The results of this finding reveal that using oligothiophene copolymer can enhance the photovoltaic performance and the stability of inverted OIHPSCs in the ambient environment.

This study was carried out with one of the physiochemical techniques of coal sample beneficiation using froth flotation technique for upgrading the quality of Achibo-Sombo-Dabaso coal, southwestern Ethiopia. The investigations aimed to beneficiate high impure Ethiopian coal and to minimize its impurities present, so that it can replace the imported coal and the environmental pollution generated during combustion is reduced. The proximate and ultimate characterization studies show that the raw coal samples contain 11.81–20.27% moisture, 22.47–36.58% ash, 22.74–34.85% volatile matter, 23.85–38.31% fixed carbon, 1.22–1.44% nitrogen, 0.57–1.9% sulfur with 3243.59–5295.34 kcal/kg calorific value. Froth flotation experiments were carried out on the raw coal samples at varying parameters of collector dosages (0.0095 kg/ton, 0.0283 kg/ton, 0.0472 kg/ton, 0.0661 kg/ton and 0.085 kg/ton of diesel oil), frother dosages (0.0922 kg/ton, 0.1845 kg/ton, 0.2767 kg/ton, 0.3689 kg/ton and 0.4611 kg/ton of n-octanol) and particle size (500–250, 250–125, 125-63 μm). The experimental results for the treated coal samples are 8.12–14.02% moisture, 7.49–13.62% ash, 21.92–30.64% volatile matter, 44.47–55.87% fixed carbon, 0.52–0.92% nitrogen, 0.25–0.41% sulfur content with 5243.40–6531.46 kcal/kg of calorific value. The results of this study indicate that the treated coal samples are relative with high calorific value, fixed carbon and low ash content compared to the raw samples. The coal samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) to understand the flotation and size distribution of coal. Therefore, the froth flotation technique at parameters of collector dosages (0.0472 kg/ton of diesel oil), frother dosages (0.3689 kg/ton of n-octanol) and particle size (125-63 μm) is effective to increase the calorific value above 5000 kcal/kg and increment carbon content of Achibo-Sombo-Dabaso coal that suitable as an energy source in cement and steel industries.

The focus of this research was to synthesize biogenic silver nanoparticles (AgNPs) using the essential oil of the aerial part of Cyclospermum leptophyllum (CLEO) and investigate their colorimetric determination of metallic ions. In the synthesis of CLEO mediated AgNPs (CLEO-AgNPs), the one-factor-at-a-time method was used to optimize the reaction parameters. Ultraviolet-visible (UV-Vis) peak of CLEO-AgNPs was determined at 426 nm. Fourier transform-infrared (FTIR) spectra analysis identified the functional groups participating in the bio-reducing, capping, and stabilizing processes in the CLEO-AgNPs synthesis. Scanning electron microscope (SEM) image demonstrated the predominately spherical shape and the average size of 70.86+1.80 nm of CLEO-AgNPs. Energy dispersive X-ray spectroscopy (EDX) peak profile depicted the presence of Ag elements in CLEO-AgNPs. The X-ray diffraction (XRD) peaks observed at 38.5°, 44°, 65°, and 77° which represent Ag(111), Ag(200), Ag(220), and Ag(311) lattice faces, respectively. The average zeta nanosize, zeta potential, and polydispersity index of CLEO-AgNPs were determined as 69.70 nm, -43.5 mV, and 0.256, respectively. The stability test exhibited the prolonged storage stability of CLEO-AgNPs for over six months at room temperature. CLEO-AgNPs demonstrated the potential colorimetric detection of K+, Mg2+, Al3+, Cr6+, Mn2+, Fe3+, Ni2+, Cu2+, Zn2+, Hg2+, Pb2+, and Cd2+ ions in the real samples. [ABSTRACT FROM AUTHOR]