Enhanced Emission Using Thin Li-Halide Cathodic Interlayers for Improved Injection into Poly(p-phenylene vinylene) Derivative PLEDs

In this study, the effects of thin Li-halide cathodic interlayers on electron injection were examined for electroluminescent layers of polymer light-emitting diodes (PLEDs). An order of magnitude increase in current density is observed as Li-halide salts are varied down the group VII column of the periodic table. When considering luminance, devices with a LiCl interlayer were 2.3× greater than those with LiF, whereas devices with LiBr were 2.8× greater, while concurrently lowering the turn-on voltage. This resulting enhanced current density and subsequent luminance could be due to a lowered work-function difference at the cathode created by either the Li-halides dissociation-induced doping of the polymer surface or an interfacial dipole of ionic Li-halide compound, leading to band bending

Household water sharing: A review of water gifts, exchanges, and transfers across cultures

Water sharing offers insight into the everyday and, at times, invisible ties that bind people and households with water and to one another. Water sharing can take many forms, including so-called “pure gifts,” balanced exchanges, and negative reciprocity. In this study, we examine water sharing between households as a culturally embedded practice that may be both need-based and symbolically meaningful. Drawing on a wide-ranging review of diverse literatures, we describe how households practice water sharing cross-culturally in the context of four livelihood strategies (hunter-gatherer, pastoralist, agricultural, and urban). We then explore how cross-cutting material conditions (risks and costs/benefits, infrastructure and technologies), socioeconomic processes (social and political power, water entitlements, ethnicity and gender, territorial sovereignty), and cultural norms (moral economies of water, water ontologies, and religious beliefs) shape water sharing practices. Finally, we identify five new directions for future research on water sharing: conceptualization of water sharing; exploitation and status accumulation through water sharing, biocultural approaches to the health risks and benefits of water sharing, cultural meanings and socioeconomic values of waters shared; and water sharing as a way to enact resistance and build alternative economies. This article is categorized under: Human Water > Value of Water Human Water > Rights to Water