Effect of hot-casted NiO hole transport layer on the performance of perovskite solar cells

Mamun, Abdullah Al,Ava, Tanzila Tasnim,Abdel-Fattah, Tarek M.,Jeong, Hyeon Jun,Jeong, Mun Seok,Han, Seonhye,Yoon, Hargsoon,Namkoong, Gon Elsevier Science B.V., Amsterdam. 2019 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.188 No.-

<P><B>Abstract</B></P> <P>NiO is extensively studied as a hole transport layer in perovskite solar cells but syntheses of NiO precursor involves toxic chemicals and time-consuming processes. Moreover, the synthesized NiO contains surface defects acting as trapping sites at the NiO/perovskite interfaces, resulting in poor charge extraction, hysteresis and light soaking. In this manuscript, we developed a non-toxic methodology for NiO precursor solution by using a simple mixture of NiO powder and HCl in an air environment. In addition, a new hot-casting technique was developed to successfully fabricate densely-packed, less defective NiO films. Interestingly, the hot-casting temperature was found to significantly affect morphology, film coverage and surface defects of NiO films. When a hot-casting temperature was below 100 °C, non-uniform NiO films were sparsely formed on the FTO surface and were characterized by defects in the form of hydroxyl groups and water on the surface. Such defective NiO films resulted in severe hysteresis and light soaking effect due to the trapped charges at the defective NiO/perovskite interface of perovskite solar cells. In contrast, when the hot-casting temperature was 120 °C, the NiO film formed densely-packed morphologies, covering the FTO surface. Furthermore, this film exhibited an ordered chemistry with strong Ni-O octahedral bonding and facilitated charge extraction at NiO/perovskite interface, resulting in a negligible hysteresis and light soaking. Finally, this non-toxic and simple method of fabricating NiO film will assist further development of perovskite solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A quick, simple, inexpensive, and non-toxic methodology was developed for preparing NiO precursor solution. </LI> <LI> A new hot-casting technique was developed to fabricate densely-packed, less defective NiO films. </LI> <LI> Hot-casted NiO resulted in a negligible hysteresis and light soaking of perovskite solar cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Lead Sorption by Carbon Nanofibers Grown on Powdered Activated Carbon - Kinetics and Equilibrium

Abdullah Al Mamun,Yehya M. Ahmed,Ma'an Fahmi R. AlKhatib,Ahmad Tariq Jameel,Mohammed Abdul Hakeem Abdul Rahman AlSaadi 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.2

Carbon nanofibers (CNFs) were synthesized by using a safe and less hazardous method, compared to using floating catalysts in chemical vapor deposition (CVD) process. This process used C2H2 as carbon source and oil palm kernel shell-based powdered activated carbon (PAC) as cheap solid substrate. Use of nickel (Ni2+) impregnated PAC as fixed substrate for the synthesis of CNF is one of the novelties of the research work accomplished by the authors. The PAC–CNFs porous nanocomposite product was used for the sorption of lead ions (Pb2+) from synthetic aqueous solution. Kinetics of Pb2+ adsorption and isotherms were investigated by varying initial concentration of lead and contact time. PAC–CNFs were found to remove Pb2+ better at acidic pH of about 5.5. Langmuir and Freundlich isotherms were applied to the sorption equilibrium data to find the best fitted model. Langmuir isotherm model with R2=0.965 fitted the adsorption data better than the Freundlich isotherm. The kinetic processes of Pb2+ adsorption on CNFs were investigated by applying different kinetic models, namely zero-order, pseudo-first-order and pseudo-second-order. The pseudo-second-order rate equation exhibited the best results with R=0.999, qe=74.79 (mg/g) and K2=0.029 (min·g/mg). The novel nanocomposite product seemed to have the potential to remove Pb2+ ions from aqueous solution.

Experimental Investigation of Chloride Ion Penetration and Reinforcement Corrosion in Reinforced Concrete Member

Al Mamun, Md. Abdullah,Islam, Md. Shafiqul Korea Institute of Construction Engineering and Ma 2017 Journal of construction engineering and project ma Vol.7 No.1

This paper represents the experimental investigation of chloride penetration into plain concretes and reinforced concretes. The main objective of this work is to study the main influencing parameters affecting corrosion of steel in concrete. Plain cement concrete and reinforced cement concrete with different water-cement ratios and different cover depth were subjected to ponding test. Ponding of specimens were done for different periods into 10% NaCl solution. Depth of penetration of chloride solution into specimens was measured after ponding. Specimens were crushed and reinforcements were washed using $HNO_3$ solution and weight loss due to corrosion was calculated accordingly. There was a linear relationship between depth of penetration and water-cement ratio. It was also observed that, corrosion of reinforcing steel increases with chloride ponding period and with water-cement ratio. Corrosion of steel in concrete can be minimized by providing good quality concrete and sufficient concrete cover over the reinforcing bars. Water-cement ratio has to be low enough to slow down the penetration of chloride salts into concrete.

Issues in DSMC Application to the Prediction of Micro Nozzle Flow

Mamun Md Abdullah Al,Tae Ho Kim,Heuy Dong Kim 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.08

Seasonal Shift in Community Structure of Periphytic Ciliates in Estuarine Waters in the Northern Bay of Bengal, Bangladesh

Mamun Abdullah Al,Rahman Muhammed Forruq,Aysha Akhtar,Md. Wahidul Alam,Mohammad Nurul Azim Sikder,Alan Warren,Henglong Xu 한국해양과학기술원 2018 Ocean science journal Vol.53 No.4

To investigate the seasonal heterogeneity of the periphytic ciliate communities, a 1-year baseline survey was conducted in the Karnaphuli River estuary, northern Bay of Bengal, Bangladesh. A total of 54 ciliate species were recorded, including seven common and 14 dominant species. Maximum species number was in autumn whereas maximum abundance was in winter; the minimum for both occurred in summer. Multivariate analyses, i.e., canonical analysis of principal coordinates (CAP) and principal co-ordinates analysis (PCoA), revealed a clear seasonal heterogeneity of community structure and environmental variables. Multivariate correlation analysis (RELATE) demonstrated that the community structure of the periphytic ciliate communities was significantly correlated with environmental variables, and best matching analysis (BIOENV) indicated that heterogeneity of community patterns was mainly driven by water temperature, pH, dissolved oxygen, total dissolved solids and nutrients. Species richness and diversity peaked in autumn whereas species evenness peaked in summer. These results suggest that environmental conditions shape periphytic ciliate community structure, which is a potentially useful bio-indicator of estuarine water quality.

Coastal Afforestation Effect on Soil Physiochemical Properties at Sitakunda Coast of Chittagong, Bangladesh

Mamun, Abdullah-Al,Kabir, Md. Humayain,Kader, Mohammed Abdul,Hossain, Mohammed Kamal Institute of Forest Science 2021 Journal of Forest Science Vol.37 No.1

This study was conducted at Sitakunda coastal afforestation range, comprised of four beats- Bansbaria, Bakkhali, Baterkhil and Bogachattar, in Chittagong. Afforestation effects on soil physicochemical properties in comparison to adjacent barren land were analysed. In the study area, an area of 3277.33 ha was planted with Sonneratia apetala, Avecinnia officinalis, Excoecaria agallocha, Bruguiera sexangula, Ceriops decandra from 1968 to 2011. We found positive soil physicochemical changes in plantations in comparison to adjacent barren land. Soil bulk density of plantation was lower than the adjacent barren land. Soil pH and soil salinity were significantly higher in barren land whereas soil organic matter, organic carbon, nitrogen, phosphorus, potassium of plantations were higher in afforested land. Soil texture ranged from clay loam to sandy loam in different depth of these two types of land. However, this study concludes that there is clear evidence that afforestation has positive impacts on all soil properties in different location and soil depths in the study area.

Improved recovery of bioenergy and osmotic water in an osmotic microbial fuel cell using micro-diffuser assisted marine aerobic biofilm on cathode

Al-Mamun, Abdullah,Baawain, Mahad Said,Dhar, Bipro Ranjan,Kim, In S. Elsevier 2017 Biochemical engineering journal Vol.128 No.-

<P><B> <B>A</B>bstract</B></P> <P>The research work demonstrated the performance of an integrated MFC capable of recovering osmotic water and electricity using forward osmosis in a double-chambered baffled channel reactor. The potential of applying electrochemically active (EA) aerobic marine biofilms on the cathode electrode was explored by eliminating the costly Pt-catalyst, thus making the system more eco-friendly and sustainable. The bio-cathode osmotic microbial fuel cell (OsMFC) used in this study was operated by two different conditions of oxygen supplied into the marine EA biofilms (i.e., the conventional oxygen supply by perforated pipes, and the enhanced oxygen supply by micro-pore air diffuser). The system recovered a maximum electrical power, 28.90 Wm<SUP>−3</SUP> net cathodic compartments (NCC), while removing 63±8% of COD from raw domestic wastewater. The rate of osmotic water recovery was 1.46±0.04Lm<SUP>−2</SUP> h<SUP>−1</SUP>. The amount of recovered osmotic water showed a great potential for integrating osmosis into the marine bio-cathode OsMFC. The dominating bacterial communities identified in the cathodic biofilms were mainly gamma-Proteobacteria and alpha-Proteobacteria.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An osmotic microbial fuel cell is investigated for securing freshwater and clean energy. </LI> <LI> Electro-chemically active marine aerobic biofilms are applied to catalyzed cathodic reaction. </LI> <LI> Micro-diffuser aeration enhances power generation, but slightly reduces osmotic water flux. </LI> <LI> Micro-diffuser aeration shows slightly high tendency of membrane fouling due to low shear effect. </LI> </UL> </P>

DSMC Study on Supersonic Mirco-Orifice Flow

Md Abdullah Al Mamun,Huey Dong Kim 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12

Preference and Consumption Pattern of Horticultural Species in the Offshore Homestead Forest of Bangladesh

Kazi Mohammad Masum,Abdullah Al Mamun,Mohammad Mamun-Or-Rashid,M. M. Abdullah-Al-Mamun,Mohammad Nabidul Islam 강원대학교 산림과학연구소 2012 Journal of Forest Science Vol.28 No.2

An explanatory survey was conducted to assess preference and consumption pattern of horticultural species, their sources,location-wise planting preferences and diversity of these speci es in the rural homestead forest of the offshore island of Bangladesh. Assessment was done through multistage random sampling. Based on homestead size respondents were categorized into small (<0.05 ha), medium (0.05-0.25 ha) and large (>0.25 ha) and twenty from each category were selected randomly for the study. The study revealed that most of the farmer (75.5%) preferred to plant fruit tree species for future plantation followed by timber species (62.2%). But fruit-bearing plants were being gradually replaced by some exotic timber species such as Swietenia mahagoni, Acacia auriculiformis, Tectona grandis, Eucalyptus spp., etc. Diversity and abundance of fruit species was found higher in almost all homestead. A total of 41 horticultural species were identified and seven horticultural species among them were recognized as the most preferred ones in the study area. Consumption pattern was chiefly to meet the nutritional demand and to gain a quick monetary benefit. Average annual income from horticultural species was 7,183.33 Taka (US$102).

Preference and Consumption Pattern of Horticultural Species in the Offshore Homestead Forest of Bangladesh

Masum, Kazi Mohammad,Mamun, Abdullah Al,Mamun-Or-Rashid, Mohammad,Abdullah-Al-Mamun, M. M.,Islam, Mohammad Nabidul Institute of Forest Science 2012 Journal of Forest Science Vol.28 No.2

An explanatory survey was conducted to assess preference and consumption pattern of horticultural species, their sources, location-wise planting preferences and diversity of these species in the rural homestead forest of the offshore island of Bangladesh. Assessment was done through multistage random sampling. Based on homestead size respondents were categorized into small (<0.05 ha), medium (0.05-0.25 ha) and large (>0.25 ha) and twenty from each category were selected randomly for the study. The study revealed that most of the farmer (75.5%) preferred to plant fruit tree species for future plantation followed by timber species (62.2%). But fruit-bearing plants were being gradually replaced by some exotic timber species such as Swietenia mahagoni, Acacia auriculiformis, Tectona grandis, Eucalyptus spp., etc. Diversity and abundance of fruit species was found higher in almost all homestead. A total of 41 horticultural species were identified and seven horticultural species among them were recognized as the most preferred ones in the study area. Consumption pattern was chiefly to meet the nutritional demand and to gain a quick monetary benefit. Average annual income from horticultural species was 7,183.33 Taka (US$102).