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

In2_{2}O3_{3}:H-Based Hole-Transport-Layer-Free Tin/Lead Perovskite Solar Cells for Efficient Four-Terminal All-Perovskite Tandem Solar Cells

Narrow-band gap (NBG) Sn–Pb perovskites with band gaps of ∼1.2 eV, which correspond to a broad photon absorption range up to ∼1033 nm, are highly promising candidates for bottom solar cells in all-perovskite tandem photovoltaics. To exploit their potential, avoiding optical losses in the top layer stacks of the tandem configuration is essential. This study addresses this challenge in two ways (1) removing the hole-transport layer (HTL) and (2) implementing highly transparent hydrogen-doped indium oxide In2O3:H (IO:H) electrodes instead of the commonly used indium tin oxide (ITO). Removing HTL reduces parasitic absorption loss in shorter wavelengths without compromising the photovoltaic performance. IO:H, with an ultra-low near-infrared optical loss and a high charge carrier mobility, results in a remarkable increase in the photocurrent of the semitransparent top and (HTL-free) NBG bottom perovskite solar cells when substituted for ITO. As a result, an IO:H-based four-terminal all-perovskite tandem solar cell (4T all-PTSCs) with a power conversion efficiency (PCE) as high as 24.8% is demonstrated, outperforming ITO-based 4T all-PTSCs with PCE up to 23.3%

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

Death and organization: Heidegger’s thought on death and life in organizations

Mortality has not been given the attention it deserves within organization studies. Even when it has been considered, it is not usually in terms of its implications for own lives and ethical choices. In particular, Heidegger’s writing on death has been almost entirely ignored both in writing on death and writing on organizational ethics, despite his insights into how our mortality and the ethics of existence are linked. In this paper, we seek to address this omission by arguing that a consideration of death may yield important insights about the ethics of organizational life. Most important of these is that a Heideggerian approach to death brings us up against fundamental ethical questions such as what our lives are for, how they should be lived and how we relate to others. Heideggerarian thought also reconnects ethics and politics, as it is closely concerned with how we can collectively make institutions that support our life projects rather than thwart or diminish them

Puritans, visionaries and survivors

All readings take place in the here-and-now, even of texts written back there and then. Nowhere in management and organization theory has this been truer of anyone than Max Weber. Unread in English during his lifetime, it was nearly 30 years after his death before his ideas had much impact. When they did, they were read in a context and tradition years away from those in which they were conceived. And, ever since, they have been subject to systematic reinterpretation on the one hand and neglect on the other. The paper addresses how one might use Weber today, in terms of his sensitivity to current issues, such as sustainability, as well as the still largely unacknowledged foundation that Weber constructed for contemporary cultural studies. The paper will bring these two themes together, using analysis of contemporary equivalents to the popular culture that formed the basis for some of Weber's own investigations. Copyright © 2005 SAGE Publications

Rapha: weaving story strands of luxury

British cycling company Rapha presents itself as a premium brand offering high quality apparel, concierge travel services, boutique 'clubhouses' and beautiful publications. Since 2004, it has enjoyed year-on-year growth and in 2016 sales increased almost 30% to £63 million (Wood 2017). This chapter critiques how we can know that and know how (Roberts and Armitage 2016) Rapha is a luxury brand – contrary to its labelling as 'premium' – and how this can be established through socio-cultural sense-making of the brand offerings, through critical textual analysis. This chapter interrogates how Rapha has developed a luxurious 'storyworld' (Abbott 2008) and charts how story strands of luxury are woven through its material artefacts, texts and environments, acting as a symbolic 'red thread' that cohesively binds the brand together