Relationship between personal debt arrears and risk attitude - cross country evidence

Purpose: The paper's objective is to compare differences between people from four European countries in terms of however having or never having debt difficulty is related to risk attitude. Design/Methodology/Purpose: This paper aims to check however having or never having debt arrears is related to risk attitude. The hypothesis put forward is that independently of country, people who have never been in debt arrears are less risk-seeking than people who have ever had arrears; however, the differences in risk aversion between indebted and not indebted individuals are not equal among the nationalities examined. Findings: The hypothesis advanced was confirmed. It can be observed that people who have never had debt arrears are more risk-averse in most cases. In each country, the group of respondents with problems repaying debt rated themselves higher in terms of being a risk-taker and more open to risk than other people. However, the ratings differed in their levels across the different countries. Moreover, in each country, people with debt arrears when asked to give someone advice on investment were more likely to choose the risky option, but the percentages differed among countries. Practical Implications: Present and past debtors are not the same in terms of risk attitude, and sometimes even past debtors resemble more non-debtors in risky behavior Originality: The article results from a large-scale survey (the smallest sample consisted of 802 subjects, the biggest of 1200) conducted in Spain, Italy, Poland, and Romania regarding the emergence of overdue debt.peer-reviewe

Nanoscale structure, dynamics and power conversion efficiency correlations in small molecule and oligomer-based photovoltaic devices

Photovoltaic functions in organic materials are intimately connected to interfacial morphologies of molecular packing in films on the nanometer scale and molecular levels. This review will focus on current studies on correlations of nanoscale morphologies in organic photovoltaic (OPV) materials with fundamental processes relevant to photovoltaic functions, such as light harvesting, exciton splitting, exciton diffusion, and charge separation (CS) and diffusion. Small molecule photovoltaic materials will be discussed here. The donor and acceptor materials in small molecule OPV devices can be fabricated in vacuum-deposited, multilayer, crystalline thin films, or spin-coated together to form blended bulk heterojunction (BHJ) films. These two methods result in very different morphologies of the solar cell active layers. There is still a formidable debate regarding which morphology is favored for OPV optimization. The morphology of the conducting films has been systematically altered; using variations of the techniques above, the whole spectrum of film qualities can be fabricated. It is possible to form a highly crystalline material, one which is completely amorphous, or an intermediate morphology. In this review, we will summarize the past key findings that have driven organic solar cell research and the current state-of-the-art of small molecule and conducting oligomer materials. We will also discuss the merits and drawbacks of these devices. Finally, we will highlight some works that directly compare the spectra and morphology of systematically elongated oligothiophene derivatives and compare these oligomers to their polymer counterparts. We hope this review will shed some new light on the morphology differences of these two systems

Facile synthesis of metal-free organic dyes featuring a thienylethynyl spacer for dye sensitized solar cells

In this article, we report the facile synthesis of metal-free dyes 6 and 7, their solution-based optical and redox properties and their use as sensitizers in dye-sensitized solar cells (DSSCs). Our studies indicate that the addition of the second thiophene unit in dye 7, decreases the oxidation and reduction potential and consequently the band gap of the molecule compared to 6. Furthermore, increasing the length of the conjugated spacer also affects on the properties of the DSSCs, with dye 7 providing a higher power conversion efficiency compared to 6 (η = 4.49 versus 3.23%)

Efficiency evaluation of using resources by hospital units

Purpose: The aim of this article is to present an efficient evaluation methodology for the hospital resources used in a study on units of healthcare system and their analysis in the organizational and legal forms. Design/Methodology/Approach: A research group constituted 48 health care units has been used. For the empirical part, a non-parametric DEA method was used to evaluate the efficiency of functioning of hospital units (surgical and internal medicine, both public and private) for 2014-2018. All the units that were qualified to the study had a contracted hospital agreement. Findings: Past analysis on the units of a healthcare system proved that efficiency of the usage of material or personal resources was underestimated and only a financial result was vital which in the units of healthcare system cannot play a major role. The authors proved that to manage efficiency it has to be previously measured with usage of the DEA method and the outcomes can be treated as a basis for developing and publishing detailed ranking lists that allow comparison between medical units. Results did not confirm that public health care units were less efficient than private units, which is very often taken as given. Practical Implications: Presented results – together with a recommended method – apart from experimental virtue also have a huge practical value. They can be used in a process of benchmarking which is getting more important as one of modern managing conception and is easily used in a health care sector. Originality/Value: Limitation of the resources in a system of health care determines necessity to constantly control the area of input-outcome. Conducted studies and conclusions constitute a new view on efficiency of health care units. The authors believe that it is necessary to continue studies in the regional field and also on different levels of protection systems.peer-reviewe

Charge transfer dynamics in conjugated polymer/MoS2 organic/2D heterojunctions

Heterojunctions between organic and two-dimensional (2D) semiconductors show promising applications in ultrathin electronic and optoelectronic devices, including field-effect transistors, light-emitting diodes, and photovoltaics. These organic/2D heterojunctions form ideal interfaces due to the lack of dangling bonds at the surfaces of the neat (i.e., individual) materials and their propensity to interact via van der Waals forces. Despite this, organic/2D heterojunction devices have had relatively low quantum efficiencies, suggesting limitations on the charge transport within these devices. Understanding the charge transfer dynamics across organic/2D semiconductor interfaces at fundamental time scales is an important part of overcoming these limitations. In this work, we investigate the photoexcited charge carrier dynamics in organic/2D heterojunctions comprised of large-area monolayer MoS2 and solution-deposited organic semiconducting conjugated polymer thin-films. Using photoluminescence and femtosecond transient absorption spectroscopy, we compare the efficiencies of charge transfer for three different conjugated polymer/MoS2 heterojunctions: P3HT, PCDTBT, and PTB7. We show that electron transfer occurs from MoS2 to P3HT in under 9 ps, and from MoS2 to PCDTBT or PTB7 in under 120 fs. Despite this, we demonstrate that the P3HT/MoS2 heterojunction is the most efficient because the transferred charges have an order-of-magnitude increase in their lifetimes, giving rise to enhanced photoluminescence. This work will help guide designs of future organic/2D heterojunctions using scalable fabrication technologies

Charge Photogeneration in Organic Photovoltaics: Role of Hot versus Cold Charge-Transfer Excitons

The role of excess excitation energy on long-range charge separation in organic donor/acceptor bulk heterojunctions (BHJs) continues to be unclear. While ultrafast spectroscopy results argue for efficient charge separation through high-energy charge-transfer (CT) states within the first picosecond (ps) of excitation, charge collection measurements suggest excess photon energy does not increase the current density in BHJ devices. Here, the population dynamics of charge-separated polarons upon excitation of high-energy polymer states and low-energy interfacial CT states in two polymer/fullerene blends from ps to nanosecond time scales are studied. It is observed that the charge-separation dynamics do not show significant dependence on excitation energy. These results confirm that excess exciton energy is not necessary for the effective generation of charges