Psychotherapy in historical perspective

This article will briefly explore some of the ways in which the past has been used as a means to talk about psychotherapy as a practice and as a profession, its impact on individuals and society, and the ethical debates at stake. It will show how, despite the multiple and competing claims about psychotherapy’s history and its meanings, historians themselves have, to a large degree, not attended to the intellectual and cultural development of many therapeutic approaches. This absence has the potential consequence of implying that therapies have emerged as value-free techniques, outside of a social, economic and political context. The relative neglect of psychotherapy, by contrast with the attention historians have paid to other professions, particularly psychiatry, has also underplayed its societal impact. This article will foreground some of the instances where psychotherapy has become an object of emerging historical interest, including the new research that forms the substance of this special issue of History of the Human Sciences

a-Si:H/c-Si Heterojunction Solar Cells on 50 µm Thick Wafers With Rear Point Contacts

International audienceCrystalline silicon thin film processes for thicknesses in the 20-80 µm range are more and more interesting given the issue of silicon shortage. Layer Transfer Processes (LTP) were widely investigated to obtain thin films because of the unavailability of suitable wire sawing. LTP avoids hazardous handling with fragile layers and silicon waste during sawing. In addition, a-Si:H/c-Si heterojunction solar cells are well suited to reduce the photovoltaic power cost. High efficiency on bulk substrate has been demonstrated by Sanyo Corporation and the low temperature process, less than 250 °C, ensures economical gain. In this paper, we present the fabrication of 26 cm 2 solar cells on 50-70 µm thick CZ wafers. The emitter is obtained either by a-Si:H (n +) deposition or by phosphorus diffusion. A 10 % efficiency solar cell on 52 µm thick silicon substrate has been achieved with a-Si:H/c-Si heterojunction. Further improvement is expected with an optimized ITO deposition and a progress in fill factor. Moreover, we also evaluate the effects of rear point contacts obtained by lithography through a dielectric layer. LBIC measurement has been used and a relative 10 % enhancement of photogenerated current has been observed at wavelength 980 nm on no contacted area compared to point contacts area. Moreover defects at the silicon metallization interface can be revealed. Such characterization has been made on 45 µm thick transferred layer

Efficient Micrometer Thick Bifacial Perovskite Solar Cells

Perovskite solar cells have become promising candidates for thin-film photovoltaics (PV), but many record cells suffer from losses in current (≈3-4 mA cm−2). This is due to the choice of superstrate configurations (i.e., glass-side illumination) and thin absorber layers, typically on the order of ≈500 nm. Illumination through a top transparent conductive oxide electrode (substrate configuration) using LiF and Al2Ox as anti-reflective coatings leads to reflectance losses below 1% is demonstrated. When combined with 1 µm thick absorber layers, substrate configurated bifacial devices have power conversion efficiencies >20%, with minimized reflection losses approaching 98% of their detailed-balance limits and higher Jsc than their monofacial counterparts. Further analysis is conducted to show there is still a significant fraction of current lost due to poor charge-carrier extraction (e.g., resistive or low mobility contacts). This is studied by a direct comparison of photoluminescence at short-circuit versus open-circuit estimating a 4.5% loss in charge-carrier collection