Oes the molecular weight of polymers affect the performance of polymer Research Paper

Oes the molecular weight of polymers affect the performance of polymer (organic) solar cells - Research Paper Example (b) Key among these factors is the physical properties of bulk heterojunction, which plays a significant role (Kingsley et al. 22). Components of bulk heterojunction require a broad absorption response in the solar spectrum, which then ensure efficient harvesting of the photons. (c) In addition, the energy levels donor, which is usually a conjugated polymer, need to match with that of the electron acceptor, which typically is a derivative of fullerene (Intemann et al. 3190). This implies that the donor polymer needs to possess a deep highest occupied molecular orbital, which will ensure a large open circuit voltage (Xiao et al. 75). (a) The molecular weight of a conjugated polymer influences the effective conjugated chain (Liu et al. 12165). Therefore, molecular weight makes the electrical and optical properties of the polymers to vary, which improves the performance of polymer solar cells. (b) Prior to conducting and finalizing the research papers, the writers expect that correlations will be evident between the molecular weight and voltage, light absorbance, and current density of solar cells. These correlations will be further investigated and addressed in depth in the final report. Intemann, Jeremy J. et al. â€Å"Molecular Weight Effect on the Absorption, Charge Carrier Mobility, and Photovoltaic Performance of an Indacenodiselenophene-Based Ladder-Type Polymer.† Chemistry of Materials 25.15 (2013): 3188–3195. ACS Publications. Web. 5 Mar. 2015. Kingsley, James W. et al. â€Å"Molecular Weight Dependent Vertical Composition Profiles of PCDTBT: PC71BM Blends for Organic Photovoltaics.† Scientific Reports 4 (2014): n. pag. www.nature.com. Web. 5 Mar. 2015. Xiao, Zeyun et al. â€Å"Effect of Molecular Weight on the Properties and Organic Solar Cell Device Performance of a Donor–Acceptor Conjugated Polymer.† Polymer Chemistry (2015): n. pag. pubs.rsc.org. Web. 5 Mar.

The death penalty Research Paper Example | Topics and Well Written Essays - 750 words

The death penalty - Research Paper Example Notably, the rate of death penalty punishments is decreasing although some countries are still practicing it. Indeed, Amnesty International notes that USA, Japan, some African states, China, many Asian and Middle Eastern countries retains the death penalty punishment (Amnesty international 1). As such, death penalty exists in many countries and many American citizens, political leaders, and religious leaders have been victims of the death penalty. The continued use of the death penalty is because of its effectiveness in controlling capital offences and rendering justice. Various countries and religions have different definitions of crimes that may lead to a death penalty as well as distinct methods of carrying out the punishment. Crimes that may lead to a death penalty include murder, treason, rape, terrorism, and even adultery in the Muslim religion. However, in all cases, intentional murder leads to a death penalty. Methods of executing a death penalty include hanging, stoning, lethal chemicals, firing squad, and beheading. Nevertheless, in all religions, there must be enough evidence against a convict in a due court process for the court to prescribe a death penalty where the burden of proof rests with the complainant or the prosecutor. There have been numerous debates and opinions in support and against the death penalty where Amnesty international condemns the death penalty in all cases regardless of the characteristics of the offender, nature of crime, or the method of execution (Amnesty international 1). Moreover, the Universal Declaration of Human Rights states that death penalty is a denial of the right to life (Oklahoma Coalition to Abolish the Death Penalty 1). Indeed, it confirms that the death penalty is a violent practice, and does not accord justice to either the accused or the offended (Center for Constitutional Rights 1). Proponents of