This paper reports the utilization of ZnO nanorod arrays (NRAs) doped with various concentrations of Ga (0, 0.5, 1, 2, and 3 at %) as electron acceptors in organic solar cells. The donor, poly(3-hexylthiophene) (P3HT), was spin coated onto Ga-doped ZnO NRAs that were grown on fluorine-doped tin oxide (FTO) substrates, followed by the deposition of a Ag electrode by a magnetron sputtering method. Adjusting the Ga precursor concentration allowed for the control of the structural and optical properties of ZnO NRAs. The short circuit current density increased with increasing Ga concentration from 0 to 1 at %, mainly because of improved exciton dissociation and increased charge extraction. Meanwhile, the reduced charge recombination and lower hole leakage current led to an increase in the open circuit voltage with Ga concentrations up to 1 at %. The device with the optimum Ga concentration of 1 at % exhibited power conversion efficiency nearly three times higher compared to the device without Ga doping. This finding suggests that the incorporation of Ga can be a simple and effective approach to improve the photovoltaic performance of organic solar cells.
The crystallographic plane of the ZnO nanocrystals photocatalyst is considered as a key parameter for an effective photocatalysis, photoelectrochemical reaction and photosensitivity. In this paper, we report a simple method for the synthesis of a new (101) high-energy plane bounded ZnO nanocubes photocatalyst directly on the FTO surface, using a seed-mediated ultrasonic assisted hydrolysis process. In the typical procedure, high-density nanocubes and quasi-nanocubes can be grown on the substrate surface from a solution containing equimolar (0.04 M) zinc nitrate hydrate and hexamine. ZnO nanocubes, with average edge-length of ca. 50 nm, can be obtained on the surface in as quickly as 10 min. The heterogeneous photocatalytic property of the sample has been examined in the photodegradation of methyl orange (MO) by UV light irradiation. It was found that the ZnO nanocubes exhibit excellent catalytic and photocatalytic properties and demonstrate the photodegradation efficiency as high as 5.7 percent/μg mW. This is 200 times higher than those reported results using a relatively low-powered polychromatic UV light source (4 mW). The mechanism of ZnO nanocube formation using the present approach is discussed. The new-synthesized ZnO nanocubes with a unique (101) basal plane also find potential application in photoelectrochemical devices and sensing.
Adolescence is the developmental process of becoming an adult. This journey of physical and psychological maturation is filled with challenges and hormonal chaos, and teenagers experience unhappiness at times. From a psychological perspective, this study aimed to examine the association between motivation, self-esteem and happiness; and to explore the mediating role of motivation in the association between self-esteem and happiness among adolescents in Malaysia. 480 secondary school students were recruited using a multistage cluster sampling method and answered the Malay versions of the Subjective Happiness, Brief Motivation and Rosenberg Self-esteem scales. Both self-esteem and motivation were found positively correlated to happiness. The hypothetical mediating role of motivation on the association between self-esteem and happiness was also supported, indicating that individuals with higher self-esteem have higher motivation which may result in greater happiness. Since the direct association between self-esteem and happiness remained significant, a partial mediation of adolescents' motivation between self-esteem and happiness is indicated. The results showed that perceived self-esteem plays a role in predicting happiness and the presence of motivation enhances happiness, providing an insight to nurture happier adolescents for parents and educators in Malaysia.
Perovskite solar cells (PSCs) have raised research interest in scientific community because their power conversion efficiency is comparable to that of traditional commercial solar cells (i.e., amorphous Si, GaAs, and CdTe). Apart from that, PSCs are lightweight, are flexible, and have low production costs. Recently, graphene has been used as a novel material for PSC applications due to its excellent optical, electrical, and mechanical properties. The hydrophobic nature of graphene surface can provide protection against air moisture from the surrounding medium, which can improve the lifetime of devices. Herein, we review recent developments in the use of graphene for PSC applications as a conductive electrode, carrier transporting material, and stabilizer material. By exploring the application of graphene in PSCs, a new class of strategies can be developed to improve the device performance and stability before it can be commercialized in the photovoltaic market in the near future.
In recent years, there has been a rise in studies aimed at better understanding the needs and traits of emerging adults and the role that higher education institutions play in their development and success. Despite the relevance of higher education institutions to the emerging adulthood development, there has been scant work done to synthesise the literature on this topic. A bibliometric method was utilised to retrieve 2484 journal articles from Web of Science (WoS). Utilizing co-citation analysis and co-word analysis, we determined the most influential publications, mapped the knowledge structure, and predicted future trends. The results of the co-citation analysis indicate five clusters, while the co-word analysis indicates four. The results could be used as a roadmap for the future of research on emerging adults by a variety of interested parties, including policymakers, university administrators, funders, and academics.
Food waste is a global challenge that threatens the sustainable development of human societies. Although food waste is produced in all stages of the food supply chain, household food waste is the biggest contributor to the food waste fraction. In this research, we systematically reviewed 54 empirical studies to explore drivers and barriers to household food waste reduction and prevention. Key aspects, such as comprehension and perception of food waste issues, practices and lifestyles, were examined. Our findings suggest that a great understanding of the impact of one's food waste on health, environment and economy directly promotes food waste management. Additionally, the food waste issue is not attributed to a single factor, it may differ varies across countries. The majority of the reviewed literature on household food waste comes from European countries, where similar geographical, economic and cultural characteristics may lead to comparable drivers and barriers. This could be the reason for showing optimistic experience to the respective food waste management interventions. However, the applicability of these findings and interventions to regions beyond Europe are uncertain. Future studies should also be expanded to include regions such as Asia, North America, Africa, Oceania, Latin America and the Caribbean. To support the sustainable management of household food waste, mapping country-specific food waste determinants is crucial in developing easy-to-implement food waste interventions that can specifically address the food waste issue in each country.
This study aimed to generate localized knowledge by investigating the perceptions and experiences of preadolescent grandchildren and grandparents regarding grandparenting and intergenerational interactions and how these processes were related to the social skills of preadolescents from three ethnic groups in Malaysia. Using a concurrent quantitative-qualitative mixed method research design, Chinese, Malay, and Indian preadolescents (N = 465; ages 9-12 years old; M = 10.27 years; SD = 1.03) from rural areas in Malaysia completed a self-administered quantitative survey; furthermore, 25 grandparents participated in one-on-one interviews. Survey findings showed that preadolescent grandchildren who reported higher grandparental warmth and support had greater social skills, mediated by positive grandparent-grandchildren (GP-GC) relationships. The GP-GC relationship and preadolescent social skills association was stronger for skipped generation compared to three-generation households. Interview findings revealed that grandparents expressed unconditional love and autonomy support in their grandparenting roles by guiding and encouraging their preadolescent grandchildren to make decisions. The GP-GC interactions served as a dynamic force in promoting preadolescents' social skills. By employing a decolonized approach and drawing on the lived experiences of grandparents from three ethnic backgrounds in rural Malaysia, the study provided an understanding of grandparenting practices and their general implications across the three ethnic groups. The interview responses highlighted both commonalities and specificities in grandparenting practices and relationship dynamics shaped by religious, class, and sociocultural dimensions in rural Malaysia.
This Research Article reports an unusually high efficiency heterogeneous photodegradation of methyl orange (MO) in the presence of Ag nanoparticle-loaded ZnO quasi-nanotube or nanoreactor (A-ZNRs) nanocatalyst grown on FTO substrate. In typical process, photodegradation efficiency of as high as 21.6% per μg per Watts of used catalyst and UV power can be normally obtained within only a 60-min reaction time from this system, which is 10(3) order higher than the reported results. This is equivalent to the turnover frequency of 360 mol mol(-1) h(-1). High-density hexagonal A-ZNRs catalysts were grown directly on FTO substrate via a seed-mediated microwave-assisted hydrolysis growth process utilizing Ag nanoparticle of approximately 3 nm in size as nanoseed and mixture aqueous solution of Zn(NO3)·6H2O, hexamethylenetetramine (HMT), and AgNO3 as the growth solution. A-ZNRs adopts hexagonal cross-section morphology with the inner surface of the reactor characterized by a rough and rugged structure. Transmission electron microscopy imaging shows the Ag nanoparticle grows interstitially in the ZnO nanoreactor structure. The high photocatalytic property of the A-ZNRs is associated with the highly active of inner side's surface of A-ZNRs and the oxidizing effect of Ag nanoparticle. The growth mechanism as well as the mechanism of the enhanced-photocatalytic performance of the A-ZNRs will be discussed.
Anion passivation effect on metal-oxide nano-architecture offers a highly controllable platform for improving charge selectivity and extraction, with direct relevance to their implementation in hybrid solar cells. In current work, we demonstrated the incorporation of fluorine (F) as an anion dopant to address the defect-rich nature of ZnO nanorods (ZNR) and improve the feasibility of its role as electron acceptor. The detailed morphology evolution and defect engineering on ZNR were studied as a function of F-doping concentration (x). Specifically, the rod-shaped arrays of ZnO were transformed into taper-shaped arrays at high x. A hypsochromic shift was observed in optical energy band gap due to the Burstein-Moss effect. A substantial suppression on intrinsic defects in ZnO lattice directly epitomized the novel role of fluorine as an oxygen defect quencher. The results show that 10-FZNR/P3HT device exhibited two-fold higher power conversion efficiency than the pristine ZNR/P3HT device, primarily due to the reduced Schottky defects and charge transfer barrier. Essentially, the reported findings yielded insights on the functions of fluorine on (i) surface -OH passivation, (ii) oxygen vacancies (Vo) occupation and (iii) lattice oxygen substitution, thereby enhancing the photo-physical processes, carrier mobility and concentration of FZNR based device.