Inverted perovskite solar cells with transparent hole transporting layer based on semiconducting nickel oxide

Perovskite (CH3NH3PbI3) solar cells (PSCs) were produced in the inverted architecture employing transparent nickel oxide (NiO) as hole transporting layer (HTL). The different functional layers of the photoconversion device were solution processed in ambient conditions the HTL of NiO being prepared via sol-gel and successively deposited by spin-coating. The conditions of preparation of the transparent HTL were optimized through the stabilization of the nickel-containing sol with bulky alcohols and strong inorganic acids. The photoactive layer of CH3NH3PbI3 was deposited in air at high relative humidity (ca. 50-60%). The electron selective contact was constituted by spin coated 3H-cyclopropa[1,9] [5,6]fullerene-C60-Ih-3'-butanoic acid 3'-phenyl methyl ester (PCBM) with solution processed 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, BCP) as interlayer. The deposition of CH3NH3PbI3 in ambient conditions as well as the processing of the BCP interlayer from solution simplified enormously the entire procedure of device fabrication. The largest value of photoconversion efficiency (PCE) we achieved with the inverted architecture photocells was 14 % with an average PCE of 12 %. The solar cells displayed an hysteresis-free behavior with excellent time stability of the maximum power output

Progress, highlights and perspectives on NiO in perovskite photovoltaics

The power conversion efficiency of NiO based perovskite solar cells has recently hit a record 22.1%. Here, the main advances are reviewed and the role of NiO in the next breakthroughs is discussed

Upscaling Inverted Perovskite Solar Cells: Optimization of Laser Scribing for Highly Efficient Mini-Modules

The upscaling of perovskite solar cells is one of the challenges that must be addressed to pave the way toward the commercial development of this technology. As for other thin-film photovoltaic technologies, upscaling requires the fabrication of modules composed of series-connected cells. In this work we demonstrate for the first time the interconnection of inverted modules with NiOx using a UV ns laser, obtaining a 10.2 cm2 minimodule with a 15.9% efficiency on the active area, the highest for a NiOx based perovskite module. We use optical microscopy, energy-dispersive X-ray spectroscopy, and transfer length measurement to optimize the interconnection. The results are implemented in a complete electrical simulation of the cell-to-module losses to evaluate the experimental results and to provide an outlook on further development of single junction and multijunction perovskite modules

16 years follow-up evaluation of immediate vs delayed vs. combined hormonal therapy on fertility of patients with cryptorchidism: results of a longitudinal cohort study

To investigate in a longitudinal cohort study, the best treatment to preserve fertility in cryptorchid subjects. Patients treated with immediate hormonal vs. delayed vs. combined (hormone plus surgery) therapy consecutively enrolled during the period 1987-1997, were evaluated

Breaking 1.7V open circuit voltage in large area transparent perovskite solar cells using bulk and interfaces passivation

Efficient semi-transparent solar cells can trigger the adoption of building integrated photovoltaics. Halide perovskites are particularly suitable in this respect owing to their tunable bandgap. Main drawbacks in the development of transparent perovskite solar cells are the high Voc deficit and the difficulties in depositing thin films over large area substrates, given the low solubility of bromide and chloride precursors. In this work, we develop a 2D and passivation strategies for the high band-gap Br perovskite able to reduce charge recombination and consequently improving the open-circuit voltage. We demonstrate 1cm 2 perovskite solar cells with Voc up to 1.73 V (1.83 eV QFLS) and a PCE of 8.2%. The AVT exceeds 70% by means of a bifacial light management and a record light utilization efficiency of 5.72 is achieved, setting a new standard for transparent photovoltaics. Moreover, we show the high ceiling of our technology towards IoT application due to a bifaciality factor of 87% along with 17% PCE under indoor lighting. Finally, the up-scaling has been demonstrated fabricating 20cm 2 -active area modules with PCE of 7.3% and Voc per cell up to 1.65V

Origin of Sn(II) oxidation in tin halide perovskites

Tin-halide perovskites have great potential as photovoltaic materials, but their performance is hampered by undesirable oxidation of Sn(ii) to Sn(iv). NMR proves DMSO to be a main cause of oxidation

Fluoride Chemistry in Tin Halide Perovskites

Tin is the frontrunner for substituting toxic lead in perovskite solar cells. However, tin suffers the detrimental oxidation of SnII to SnIV. Most of reported strategies employ SnF2 in the perovskite precursor solution to prevent SnIV formation. Nevertheless, the working mechanism of this additive remains debated. To further elucidate it, we investigate the fluoride chemistry in tin halide perovskites by complementary analytical tools. NMR analysis of the precursor solution discloses a strong preferential affinity of fluoride anions for SnIV over SnII, selectively complexing it as SnF4. Hard X-ray photoelectron spectroscopy on films shows the lower tendency of SnF4 than SnI4 to get included in the perovskite structure, hence preventing the inclusion of SnIV in the film. Finally, small-angle X-ray scattering reveals the strong influence of fluoride on the colloidal chemistry of precursor dispersions, directly affecting perovskite crystallization

Ion Migration‐Induced Amorphization and Phase Segregation as a Degradation Mechanism in Planar Perovskite Solar Cells

The operation of halide perovskite optoelectronic devices, including solar cells and LEDs, is strongly influenced by the mobility of ions comprising the crystal structure. This peculiarity is particularly true when considering the long‐term stability of devices. A detailed understanding of the ion migration‐driven degradation pathways is critical to design effective stabilization strategies. Nonetheless, despite substantial research in this first decade of perovskite photovoltaics, the long‐term effects of ion migration remain elusive due to the complex chemistry of lead halide perovskites. By linking materials chemistry to device optoelectronics, this study highlights that electrical bias‐induced perovskite amorphization and phase segregation is a crucial degradation mechanism in planar mixed halide perovskite solar cells. Depending on the biasing potential and the injected charge, halide segregation occurs, forming crystalline iodide‐rich domains, which govern light emission and participate in light absorption and photocurrent generation. Additionally, the loss of crystallinity limits charge collection efficiency and eventually degrades the device performance

Optimizing the “Time to pregnancy” in women with multiple sclerosis: the OPTIMUS Delphi survey

BackgroundThe debate on how to manage women affected by multiple sclerosis (MS) during reproductive age is still open, as is the issue of fertility in such patients. Main issue regard the identification of the optimal window for pregnancy and how to deal with medical therapy before and during conception. The aim of this Delphi consensus was to collect the opinions of a multidisciplinary group, involving reproductive medicine specialists and neurologists with experience in the management of multiple sclerosis women with reproductive desire.MethodsFour experts plus scientific coordinators developed a questionnaire distributed online to 10 neurologists and later discussed the responses and amended a list of statements. The statements were then distributed via an online survey to 23 neurologists (comprising the first 10), who voted on their level of agreement/disagreement with each statement. Consensus was achieved if agreement or disagreement with a statement exceeded 66%.ResultsTwenty-one statements reached consensus after two rounds of voting, leading to the following main recommendations: (1) Fertility evaluation should be suggested to wMS, in case of the need to shorten time to pregnancy and before treatment switch in women on DMTs contraindicated in pregnancy, particularly in case of highly active disease and age > 35 years. (2) ART should not be discouraged in wMS, but the use of DMTs until pregnancy confirmation should be suggested; ART may be considered in order to reduce time to pregnancy in MS women with a reduced ovarian reserve and/or age > 35 years, but in case of an expected poor ART prognosis and the need for more than one ART cycle, a switch to a high-efficacy DMD before ART should be offered. (3) Oocyte cryopreservation may be considered in women with reduced ovarian reserve, with unpredictable time to complete diagnostic workup and achieve disease control; a risk/cost–benefit analysis must be performed in women >35 years, considering the diminished ovarian reserve.ConclusionThis consensus will help MS neurologists to support family planning in wMS, respecting MS therapeutic needs while also taking into account the safety and impact of advancing age on fertility