SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: IBM

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High-quality perovskite monocrystalline films are successfully grown through cavitation-triggered asymmetric crystallization. These films enable a simple cell structure, ITO/CH3 NH3 PbBr3 /Au, with near 100% internal quantum efficiency, promising power conversion efficiencies (PCEs) >5%, and superior stability for prototype cells. Furthermore, the monocrystalline devices using a hole-transporter-free structure yield PCEs ≈6.5%, the highest among other similar-structured CH3 NH3 PbBr3 solar cells to date.

Concepts: Gene, Photoelectric effect, Solar cell, Czochralski process, Energy conversion, Energy conversion efficiency, IBM, Quantum electronics

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Morphology control of solution coated solar cell materials presents a key challenge limiting their device performance and commercial viability. Here we present a new concept for controlling phase separation during solution printing using an all-polymer bulk heterojunction solar cell as a model system. The key aspect of our method lies in the design of fluid flow using a microstructured printing blade, on the basis of the hypothesis of flow-induced polymer crystallization. Our flow design resulted in a ∼90% increase in the donor thin film crystallinity and reduced microphase separated donor and acceptor domain sizes. The improved morphology enhanced all metrics of solar cell device performance across various printing conditions, specifically leading to higher short-circuit current, fill factor, open circuit voltage and significantly reduced device-to-device variation. We expect our design concept to have broad applications beyond all-polymer solar cells because of its simplicity and versatility.

Concepts: Fluid dynamics, Solar cell, Photovoltaics, Direct current, Fill factor, IBM, P-n junction, Solar cells

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Herein we report on the synthesis of an N-annulated perylene diimide (PDI) disubstituted thieno[3,4-c]pyrrole-4,6-dione (TPD) molecular acceptor (PDI-TPD-PDI) by direct heteroarylation (DHA) methods. Three sets of DHA conditions that explore the effects of solvent, temperature, and catalyst were employed to find the optimal conditions for the synthesis of two PDI-TPD-PDI derivatives. We then selected one PDI-TPD-PDI for use as a non-fullerene acceptor in organic solar cell devices with the donor polymer PBDB-T. Active layer bulk-heterojunction blends were modified using several post-deposition treatments, including thermal annealing, solvent vapour annealing, and high boiling solvent additives. It was found that active layers cast from o-dichlorobenzene with a 3% v/v diphenylether additive yielded films with adequate phase separation, and subsequently gave the best organic solar cell performance, with power conversion efficiencies greater than 3%.

Concepts: Oxygen, Solar cell, Photovoltaics, Organic solar cell, Direct current, Energy conversion, Energy conversion efficiency, IBM

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Hole-transporting material (HTM) is an indispensable constituent in organic electronic devices, generally comprising a donor/dopant combination. We report that a disodium salt of substituted benzo[1,2- b:4,5- b']dipyrrole bearing two racemic alkanediylsulfonate anion side chains (BDPSOs) serves as a neutral, nonhygroscopic, dopant-free HTM for lead perovskite (MAPbI3) solar cells. These organic/inorganic hybrid molecules are useful for tunable orbital level and controllable solubility. A fluorinated BDPSO has an energy level matched with MAPbI3, affording an inverted-structure solar cell that performs with 17.2% efficiency with minimal hysteresis. The solar cell devices fabricated using BDPSOs showed remarkable storage and operational stability.

Concepts: Chemistry, Atom, Ion, Organic chemistry, Solar cell, Photovoltaics, Diode, IBM

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All-inorganic perovskite solar cells provide a promising solution to tackle the thermal instability problem of organic-inorganic perovskite solar cells. Herein, we designed an all-inorganic perovskite solar cell with novel structure (FTO/NiOx/CsPbI2Br/ZnO@C60/Ag), in which ZnO@C60 bilayer were utilized as the electron-transporting layers that demonstrated high carrier extraction efficiency and low leakage loss. Conse-quently, the as-fabricated all-inorganic CsPbI2Br perovskite solar cell yielded the power conversion efficiency (PCE) as high as 13.3% with Voc of 1.14 V, Jsc of 15.2 mAcm-2, and FF of 0.77. The corresponding stabilized power output (SPO) of device was demonstrated to be ∼ 12% and remarkably stable within 1000 s. Importantly, the obtained all-inorganic PSCs without encapsulation exhibited only 20% PCE loss with thermal treatment at 85 °C for 360 h, which largely outperformed the organic-species-containing PSCs. The present study is favorable to overcome the intractable issue concerning the thermal instability of perovskite solar cells.

Concepts: Solar cell, Photovoltaics, Energy conversion, Energy conversion efficiency, IBM

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We report on the photovoltaic parameters, photophysical properties, optoelectronic properties, self-assembly and morphology variation in a series of high performance donor-acceptor (D-A) π-conjugated polymers based on indacenodithiophene and quinoxaline moieties as a function of the number-average molecular weight ((“M” _“n” ) ̅), the nature of aryl substituents and the enlargement of the polymer backbone. One of the most important outcome is that from the three optimization approaches followed to tune the chemical structure towards enhanced photovoltaic performance in bulk heterojunction (BHJ) solar cell devices with the fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the electron acceptor, the choice of the aryl substituent is the most efficient rational design strategy. Incorporation of thienyl rings as substituents versus phenyl rings accelerates the electron-hole extraction process to the respective electrode, despite the slightly lower recombination lifetime and thus, improves the electrical performance of the device. Single junction solar cells based on ThIDT-TQxT feature a maximum power conversion efficiency (PCE) of 7.26%. This study provides significant insights towards understanding of the structure-properties-performance relationship for D-A π-conjugated polymers in solid state, which informs the polymer design rules toward highly efficient organic solar cells.

Concepts: DNA, Amino acid, Solar cell, Photovoltaics, Energy conversion, Energy conversion efficiency, IBM, Photovoltaic array

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Two cheliform non-fullerene acceptors, DTPC-IC and DTPC-DFIC based on a highly electron-rich core dithienopicenocarbazole (DTPC) are synthesized, showing ultra-narrow bandgaps (as low as 1.21 eV). The two-dimensional nitrogen-containing conjugated DTPC possesses strong electron-donating capability, which induces intense intramolecular charge transfer and intermolecular π-π stacking in derived acceptors. The solar cell based on DTPC-DFIC and a spectral-complementary polymer donor PTB7-Th showed a high power conversion efficiency of 10.21% and an extremely low energy loss (0.45 eV) which is the lowest among reported efficient OSCs.

Concepts: Energy, Solar cell, Photovoltaics, Organic solar cell, Energy conversion, Energy conversion efficiency, Photodiode, IBM

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Perovskite/PCBM heterojunctions are efficient for fabricating perovskite solar cells with high performance and long-term stability. In this study, an efficient perovskite/PCBM heterojunction was formed via conventional sequential deposition and one-step formation processes. Compared with conventional deposition, the one-step process was more facile, and produced a perovskite thin film of substantially improved quality due to fullerene passivation. Moreover, the resulting perovskite/PCBM heterojunction exhibited more efficient carrier transfer and extraction, and reduced carrier recombination. The perovskite solar cell device based on one-step perovskite/PCBM heterojunction formation exhibited a higher maximum PCE of 17.8% compared with that from the conventional method (13.7%). The device also showed exceptional stability, retaining 83% of initial PCE after 60 days of storage under ambient conditions.

Concepts: Semiconductor, Cadmium, Solar cell, Photovoltaics, Thin film solar cell, IBM, P-n junction, Carrier generation and recombination

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Two new hole transporting materials (HTMs) based on triphenylamine and carbazole core moieties are designed and applied in planar perovskite solar cells. 18.2% power conversion efficiency (PCE) has been achieved, and 84% of the initial performance can be retained after 50 days.

Concepts: Solar cell, Energy conversion, Energy conversion efficiency, IBM

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This article critically examines the corporate production, archival politics, and socio-legal dimensions of Corporate Mortality Files (CMFs), the largest corporate archive developed by International Business Machine’s Corporation (IBM) to systematically document industrial exposures and occupational health outcomes for electronics workers. I first provide a history of IBM’s CMF project, which amounts to a comprehensive mortality record for IBM employees over the past 40 years. Next, I explore a recent case in Endicott, New York, birthplace of IBM, where the U.S. National Institute for Occupational Safety and Health (NIOSH) studied IBM’s CMFs for workers at IBM’s former Endicott plant. Tracking the production of the IBM CMF, the strategic avoidance of this source of Big Data as evidence for determining a recent legal settlement, alongside local critiques of the IBM CMF project, the article develops what I call “late industrial necropolitics.” This article is protected by copyright. All rights reserved.

Concepts: Law, All rights reserved, Occupational safety and health, IBM, Copyright, Endicott, New York, Computing Tabulating Recording Corporation, Binghamton, New York