Cathode Interface Engineering for High Performance Planar Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cells (PSCs) have already improved their power conversion efficiency (PCE) from 3.9% to ~22.1% at present. This demonstrated that PSCs can be a promising alternative to conventional silicon solar cells. PSCs have been marked as one of the most favorable next-generation solar cells due to their high extinction coefficient, broad light absorption range and ambipolar charge transport properties, low production cost, and simple fabrication processing. Various device architectures have been designed and investigated for constructing high performance PSCs consisting of different electron transport layers (ETL) and hole transport layers (HTL). In general, PSCs are fabricated in two structures: mesoporous scaffold n-i-p and planar heterojunction p-i-n PSCs. Although mesoscopic PSCs have obtained an impressive PCE, it requires high temperature process (\u3e 450oC) for forming compact TiO2 and mesoporous TiO2 that hinders their applications that require mechanical flexibility. On the other hand, planar p-i-n PSCs have drawn attention due to low temperature processing, mechanical flexible devices. The goal of this work is to introduce a non-conjugated polymer material Polyvinylpyrrolidone (PVP) as cathode buffer layer (CBL) and understand interfacial engineering in planar p-i-n PSCs. PVP was used for the first time as a CBL in PSCs. The ETL and HTL are highly responsible to increase carrier separation, improve charge collection and reduce recombination. Additionally, the buffer layer between ETL and metal cathode (like Ca, Al, Ag) electrode in PSCs plays a crucial role in energy-level alignment, trap state passivation and PSCs film morphology. A comparative study on PSCs without and with CBL was investigated where rhodamine as CBL was considered for control device. The thickness of PVP CBL was analyzed by changing spin speed from 1000 rpm to 5000 rpm at an interval of 2000 rpm. The optimal spin speed was found at 3000 rpm, which achieved an average efficiency of 15.30%. The concentrations of PVP dissolved in isopropanol was optimized from 0.5 mg/ml to 2.0 mg/ml. There was simultaneous enhancement of short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and overall power conversion efficiency (PCE) due to incorporation of PVP. The best device achieved a PCE of 16.35%. Various device characterizations such as atomic force microscopy (AFM), scanning electron microscopy (SEM) etc. were performed to interpret the enhancement of device performance

Online Content Popularity in the Twitterverse: A Case Study of Online News

With the advancement of internet technology, online news content has become very popular. People can now get live updates of the world's news through online news sites. Social networking sites are also very popular among Internet users, for sharing pictures, videos, news links and other online content. Twitter is one of the most popular social networking and microblogging sites. With Twitter's URL shortening service, a news link can be included in a tweet with only a small number of characters, allowing the rest of the tweet to be used for expressing views on the news story. Social links can be unidirectional in Twitter, allowing people to follow any person or organization and get their tweet updates, and share those updates with their own followers if desired. Through Twitter thousands of news links are tweeted every day. Whenever there is a popular new story, different news sites will publish identical or nearly identical versions (``clones'') of that story. Though these clones have the same or very similar content, the level of popularity they achieve may be quite different due to content agnostic factors such as influential tweeters, time of publication and the popularities of the news sites. It is very important for the content provider site to know about which factor plays a important role to make their news link popular. In this thesis research, a data set is collected containing the tweets made for the 218 members of 25 distinct sets of news story clones. The collected data is analyzed with respect to basic popularity characteristics concerning number of tweets of various types, relative publication times of clone set members, tweet timing and number of tweeter followers. Then, several other factors are investigated to see their impact in making some news story clones more popular than others. It is found that multiple content-agnostic factors i.e. maximum number of followers, self promotional tweets plays an impact on news site's stories overall popularity, and a first step is taken at quantifying their relative importance

Isolation, screening and molecular identification of antagonistic bacteria against Colletotrichum gloeosporioides in mango

The study was conducted at the Postharvest and plant Biotechnology laboratory, Department of Horticulture, Patuakhali Science and Technology University, Patuakhali, Bangladesh during the period from January to July 2017 to isolate, screening and molecular identification of antagonistic bacteria against anthracnose of mango. All treatments were arranged in a completely randomized design (CRD) with replications and repeated twice. Epiphytic bacteria, isolated from leaf and fruit surfaces of mango, were tested as biocontrol agent against anthracnose disease caused by Colletotrichum gloeosporioides wherein 20 strains were confirmed as antagonistic. Molecular characterization of the three potential strains of bacteria were done by the amplification of 16S rDNA gene following the extraction of genomic DNA, polymerase chain reaction (PCR) amplification, gel electrophoresis and gel documentation. The PCR amplified products and the genomic DNA samples were sent to the Macrogen Company through Sunchon National University, Seoul, South Korea for molecular identification by sequence analysis. Among the 20 antagonistic bacteria screened in vitro by dual and concomitant tests, two isolates, namely GB6 (PSTU-Hort-8), and GB19 (PSTU-Hort-14) were recognized as antagonistics to the test fungus. Using the molecular identification systems, isolated bacterial strains PSTU-Hort-8 was identified as B. subtilis with National Center for Biotechnology Information (NCBI) accession numbers MW659188; on the other hand, strain PSTU-Hort-14 was identified as Stenotrophomonas rhizophila with NCBI accession number MW659190

Factors Affecting Employee Engagement: A Study on Private Organizations in Bangladesh

Employee engagement is essential for a company to maintain positive and productive work environment. Employee engagement and motivation at work are key factors in the success of teams and the entire organization. It improves productivity, reduces turnover rates, and fosters a positive work culture. This study explores the various ways in which organizations can increase employee engagement and motivation. The study also highlights the importance of leaders and managers in promoting a supportive work culture. Employee engagement is used to describe a worker's emotional and intellectual attachment to their organization, which expresses as dedication, enthusiasm, excitement, focused work, and enthusiasm. Engaged workers typically feel better about their jobs. Companies with engaged employees also typically generate higher profit. The study discusses the importance of work independency, equitable pay structure, professional growth, work-life balance, and cooperation of supervisor co-worker. This study identifies the most influential drivers that motivate employees to engage their job psychologically and physically. This study also determine the factor that policy maker should consider in order to increase employee engagement. Keywords: Employee engagement, work independency, work-life balance, Professional growth DOI: 10.7176/EJBM/15-16-03 Publication date:September 30th 2023

Managing environmental responsibility in small-scale manufacturing firms: Examining indigenous tanneries in Bangladesh.

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Sustainable and socially responsible business: doable reality or just a luxury? An exploratory study of the Bangladeshi manufacturing SMEs

Drawing on the ISO 26000: 2010 – Guidance on Social Responsibility, this study investigates the extent to which Bangladeshi manufacturing SMEs are incorporating sustainability into their day-to-day business activities. The findings reconfirm the existence of the so called ‘attitude-behaviour’ gap. The barriers that hinder the sustainable engagement of SMEs include corruption, a weak regulatory environment, inefficient or ill-suited government and external support, and a lack of awareness of the environmental aspects of SR. In addition, this research reveals that Bangladeshi manufacturing SMEs do, to a certain degree, implement sustainability; only those few issues that suit the owner-managers’ personal motives are addressed, while some others are neglected. Finally, it has been found that the business type and size, and the owner-managers’ educational attainments have no significant influence on the degree of adoption of sustainable and socially responsible business practices by Bangladeshi manufacturing SMEs

Impact of FDI and Joint Venture on Employment Generation: A Multi-sector Experience of Bangladesh Economy

Foreign Direct Investment (FDI) is very crucial for the sustainable development of developing countries in general and in specific for LDCs-like Bangladesh. For Bangladesh, inflow of foreign direct investment is the major stimulus for the sturdy and long-standing economic growth which is subject to the improvement of many socio-economic and political factors. As a promising hub for foreign direct investment, Bangladesh has already conquered popularity for its simplistic, liberal and most investments friendly climate throughout the globe. Being an open, flexible and promising destination for foreign direct investment, Bangladesh has been drawing attention of the global investors into a focal investment destination within South-Asian region. Its investment climate is mostly featured by munificent and alluring packages of incentives to investors. In addition, there is no discrimination between the local and foreign investors in facilitating the incentives they owe from the investment destination. The existing rules and regulations are structured in such a way so as to fully guarantee the safety of the incoming investment and their returns with gained profit or surplus. The positive and ensuring economic growth brings dramatic changes in the employment scenario of a country. The increased flow of foreign direct investment into multifarious sectors namely Agricultural, Chemical, Engineering, Textile and Service sectors significantly trims down the unemployment predicament of our country. Bangladesh has a large pool of vibrant young working force that is highly trained and skilled enough to cater the demands of the globalized world. Due to global economic recession of 2008, the financial markets were crashed jobs disappeared and growth took a sharp plunge in much of the developed world and its ripple effects were felt in the other parts of the globe. Though, many economists forecasted that Bangladesh would be severely affected by this speedy storm. Rather, the economy Bangladesh demonstrated extraordinary resilience, driven by sound macroeconomic policies, dynamic pool of private entrepreneurs and productive labour force. New and dynamic opportunities are emerging for foreign direct investment (FDl) in the traditional and emerging sectors while significantly improving involvement of female into the workforce. Keywords: FDI, Joint Venture Investment, Sectoral Investment, Employment Generation