Controlling Thin Film Morphology Formation during Gas Quenching of Slot-Die Coated Perovskite Solar Modules

Transferring record power conversion efficiency (PCE) >25 % of spin-coated perovskite solar cells (PSCs) from the laboratory scale to large-area photovoltaic modules requires significant advance in scalable fabrication techniques. In this work, we demonstrate the fundamental interrelation between drying dynamics of slot-die coated precursor solution thin films and the quality of slot-die coated gas quenched polycrystalline perovskite thin films. Well defined drying conditions are established using a temperature-stabilized, movable table and a flow-controlled, oblique impinging slot nozzle purged with nitrogen. The accurately deposited solution thin film on the substrate is recorded by a tilted CCD camera, allowing for in situ monitoring of the perovskite thin film formation. With the tracking of crystallization dynamics during the drying process, we identify critical process parameters needed for the design of optimal drying and gas quenching systems. In addition, defining different drying regimes, we derive practical slot jet adjustments preventing gas backflow and demonstrate large-area, homogeneous and pinhole-free slot-die coated perovskite thin films that result in solar cells with PCEs of up to 18.6 %. Our study reveals key interrelations of process parameters, e.g. the gas flow and drying velocity, and the exact crystallization position with the morphology formation of fabricated thin films, resulting in a homogeneous performance of corresponding solar 50x50 mm2 mini-modules (17.2 %) with only minimal upscaling loss. In addition, we validate a previously developed model on the drying dynamics of perovskite thin films on small-area for slot-die coated areas of ≥100 cm2. The study provides methodical guidelines for the design of future slot-die coating setups and establishes a step forward to a successful transfer of industrial-scale deposition systems beyond brute force optimization

Upscaling of perovskite solar modules: The synergy of fully evaporated layer fabrication and all‐laser‐scribed interconnections

Given the outstanding progress in research over the past decade, perovskite photovoltaics (PV) is about to step up from laboratory prototypes to commercial products. For this to happen, realizing scalable processes to allow the technology to transition from solar cells to modules is pivotal. This work presents all-evaporated perovskite PV modules with all thin films coated by established vacuum deposition processes. A common 532-nm nanosecond laser source is employed to realize all three interconnection lines of the solar modules. The resulting module interconnections exhibit low series resistance and a small total lateral extension down to 160 μm. In comparison with interconnection fabrication approaches utilizing multiple scribing tools, the process complexity is reduced while the obtained geometrical fill factor of 96% is comparable with established inorganic thin-film PV technologies. The all-evaporated perovskite minimodules demonstrate power conversion efficiencies of 18.0% and 16.6% on aperture areas of 4 and 51 cm$^{2}$, respectively. Most importantly, the all-evaporated minimodules exhibit only minimal upscaling losses as low as 3.1%$_{rei}$ per decade of upscaled area, at the same time being the most efficient perovskite PV minimodules based on an all-evaporated layer stack sequence

Scalable two-terminal all-perovskite tandem solar modules with a 19.1% efficiency

Monolithic all-perovskite tandem photovoltaics promise to combine low-cost and high-efficiency solar energy harvesting with the advantages of all-thin-film technologies. To date, laboratory-scale all-perovskite tandem solar cells have only been fabricated using non-scalable fabrication techniques. In response, this work reports on laser-scribed all-perovskite tandem modules processed exclusively with scalable fabrication methods (blade coating and vacuum deposition), demonstrating power conversion efficiencies up to 19.1% (aperture area, 12.25 cm2; geometric fill factor, 94.7%) and stable power output. Compared to the performance of our spin-coated reference tandem solar cells (efficiency, 23.5%; area, 0.1 cm2), our prototypes demonstrate substantial advances in the technological readiness of all-perovskite tandem photovoltaics. By means of electroluminescence imaging and laser-beam-induced current mapping, we demonstrate the homogeneous current collection in both subcells over the entire module area, which explains low losses (<5%rel) in open-circuit voltage and fill factor for our scalable modules

Population policies and education: exploring the contradictions of neo-liberal globalisation

The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation contains inherent contradictions regarding choice and uniformity. This is illustrated in this paper through an exploration of the impact of neo-liberal globalisation on population policies and programmes. The dominant neo-liberal economic ideology that has influenced development over the last few decades has often led to alternative global visions being overlooked. Many current population and development debates are characterised by polarised arguments with strongly opposing aims and views. This raises the challenge of finding alternatives situated in more middle ground that both identify and promote the socially positive elements of neo-liberalism and state intervention, but also to limit their worst excesses within the population field and more broadly. This paper concludes with a discussion outling the positive nature of middle ground and other possible alternatives

McKinesiology

Within this paper, we address how kinesiology–in a similar fashion to other disciplinary enterprises–has become enmeshed with the dictates of the market, privatization, efficiency, flexibility, and the accelerated rationalization of society, associated with the advent of late capitalism. Hence, we outline how these market considerations implicitly and explicitly privilege centrally controlled, efficiency oriented, rationally predictable, and empirically calculable ways of knowing, and of knowledge generation (Ritzer, 2004). We propose that these processes not only further wed kinesiology, the University, and implicated subjects (students as well as Professors) to the logics of the capital, but also place such concerns over human needs, civic and moral responsibilities, public values and critical contents (Giroux, 2010). These non-rational and incalculable pedagogical outcomes are crucial foundations for democracy, political freedom and equality (Brown, 2006), yet are apparently devalued in contemporary kinesiology as in other formations of (higher) education. Pace Ritzer (2006), we thus expose the epistemological McDonaldization evident with kinesiology, which we argue has resulted in a field stymied by what elsewhere has been described as its “inconvenient truth” (Andrews, 2008); namely, the intellectually and humanity limiting scientific doxa apparent and embodied within the constitution of kinesiological departments, curricular, journals, and, indeed, the kinesiology academy itself

The institutions of archaic post-modernity and their organizational and managerial consequences: The case of Portugal

The long march of modernization of the Western societies tends to be presented as following a regular sequence: societies and institutions were pre-modern, and then they were modernized, eventually becoming post-modern. Such teleology may provide an incomplete or distorted narrative of societal evolution in many parts of the world, even in the ‘post-modern heartland’ of Western Europe, with Portugal being a case in point. The concept of archaic post-modernity has been developed by a philosopher, José Gil, to show how Portuguese institutions and organizations combine elements of pre-modernity and post-modernity. The notion of an archaic post-modernity is advanced in order to provide an alternative account of the modernization process, which enriches discussion of the varieties of capitalism. Differences in historical experiences create singularities that may be considered in the analysis of culture, management and organization

27th Annual Invitational Madrigal and Chamber Choir Festival

Program listing performers and works performe

Sustained increases in atmospheric oxygen and marine productivity in the Neoproterozoic and Palaeozoic eras

A geologically rapid Neoproterozoic oxygenation event is commonly linked to the appearance of marine animal groups in the fossil record. However, there is still debate about what evidence from the sedimentary geochemical record—if any—provides strong support for a persistent shift in surface oxygen immediately preceding the rise of animals. We present statistical learning analyses of a large dataset of geochemical data and associated geological context from the Neoproterozoic and Palaeozoic sedimentary record and then use Earth system modelling to link trends in redox-sensitive trace metal and organic carbon concentrations to the oxygenation of Earth’s oceans and atmosphere. We do not find evidence for the wholesale oxygenation of Earth’s oceans in the late Neoproterozoic era. We do, however, reconstruct a moderate long-term increase in atmospheric oxygen and marine productivity. These changes to the Earth system would have increased dissolved oxygen and food supply in shallow-water habitats during the broad interval of geologic time in which the major animal groups first radiated. This approach provides some of the most direct evidence for potential physiological drivers of the Cambrian radiation, while highlighting the importance of later Palaeozoic oxygenation in the evolution of the modern Earth system

O Brasil na nova cartografia global da religião

Este artigo analisa as mudanças sociais, econômicas, culturais e religiosas que fizeram do Brasil um polo importante de produção do sagrado numa emergente cartografia global. Esta cartografia é policêntrica e entrecortada por uma miríade de redes transnacionais e multi-direcionais que facilitam o rápido movimento de pessoas, ideias, imagens, capitais e mercadorias. Entre os vetores que vamos examinar estão: imigrantes brasileiros que na tentativa de dar sentido ao processo deslocamento e de manter ligações transnacionais com o Brasil levam suas crenças, práticas, identidades religiosas para o estrangeiro, missionários e outros "entrepreneurs" religiosos, o turismo espiritual de estrangeiros que vão ao Brasil em busca de cura ou desenvolvimento espiritual, e as indústrias culturais, a mídia e a Internet que disseminam globalmente imagens do Brasil como uma terra exótica onde o sagrado faz parte intrínseca de sua cultura e natureza