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

Polymer/Inorganic Hole Transport Layer for Low-Temperature-Processed Perovskite Solar Cells

In the search for improvements in perovskite solar cells (PSCs), several different aspects are currently being addressed, including an increase in the stability and a reduction in the hysteresis. Both are mainly achieved by improving the cell structure, employing new materials or novel cell arrangements. We introduce a hysteresis-free low-temperature planar PSC, composed of a poly(3-hexylthiophene) (P3HT)/CuSCN bilayer as a hole transport layer (HTL) and a mixed cation perovskite absorber. Proper adjustment of the precursor concentration and thickness of the HTL led to a homogeneous and dense HTL on the perovskite layer. This strategy not only eliminated the hysteresis of the photocurrent, but also permitted power conversion efficiencies exceeding 15.3%. The P3HT/CuSCN bilayer strategy markedly improved the life span and stability of the non-encapsulated PSCs under atmospheric conditions and accelerated thermal stress. The device retained more than 80% of its initial efficiency after 100 h (60% after 500 h) of continuous thermal stress under ambient conditions. The performance and durability of the PSCs employing a polymer/inorganic bilayer as the HTL are improved mainly due to restraining perovskite ions, metals, and halides migration, emphasizing the pivotal role that can be played by the interface in the perovskite-additive hole transport materials (HTM) stack

Crystal engineering approach for fabrication of inverted perovskite solar cell in ambient conditions

In this paper, we demonstrate the high potentialities of pristine single-cation and mixed cation/anion perovskite solar cells (PSC) fabricated by sequential method deposition in p-i-n planar architecture (ITO/NiOX/Perovskite/PCBM/BCP/Ag) in ambient conditions. We applied the crystal engineering approach for perovskite deposition to control the quality and crystallinity of the light-harvesting film. The formation of a full converted and uniform perovskite absorber layer from poriferous pre-film on a planar hole transporting layer (HTL) is one of the crucial factors for the fabrication of high-performance PSCs. We show that the in-air sequential deposited MAPbI3-based PSCs on planar nickel oxide (NiOX) permitted to obtain a Power Conversion Efficiency (PCE) exceeding 14% while the (FA,MA,Cs)Pb(I,Br)3-based PSC achieved 15.6%. In this paper we also compared the influence of transporting layers on the cell performance by testing material depositions quantity and thickness (for hole transporting layer), and conditions of deposition processes (for electron transporting layer). Moreover, we optimized second step of perovskite deposition by varying the dipping time of substrates into the MA(I,Br) solution. We have shown that the layer by layer deposition of the NiOx is the key point to improve the efficiency for inverted perovskite solar cell out of glove-box using sequential deposition method, increasing the relative efficiency of +26% with respect to reference cells

Perovskite solar cell improvement by gold nanoparticles prepared by laser ablation in liquid

Abstract Improving performance of lead halide perovskites solar cells (PSC) by nanoparticles (NPs) with localized surface-plasmon resonances is one of the most actively developing direction in modern photovoltaics. For this purpose, we propose to use simple and cheap way for NPs fabrication based on laser ablation of gold target in liquid, which can be added in any layer of PSC. By using these NPs we improve CH3NH3PbI3 (MAPbI3) perovskite-based solar cells performance from 17.7 to 18.6% via the increase of fill factor and voltage at zero current. The chosen concentration of Au NPs in the devices does not raise parasitic absorption, whereas the external quantum efficiency grows in all working distance of PCS. The proposed method can be simply implemented for PSCs with various compositions and architectures

Beyond 17% stable perovskite solar module via polaron arrangement of tuned polymeric hole transport layer

Operational stability of perovskite solar cells (PSCs) is rapidly becoming one of the pressing bottlenecks for their upscaling and integration of such promising photovoltaic technology. Instability of the hole transport layer (HTL) has been considered as one of the potential origins of short life-time of the PSCs. In this work, by varying the molecular weight (MW) of doped poly(triarylamine)(PTAA) HTL, we improved by one order of magnitude the charge mobility inside the HTL and the charge transfer at the perovskite/HTL interface. We demonstrate that this occurs via the enhancement of polaron delocalization on the polymeric chains through the combined effect of doping strategy and MW tuning. By using high MW PTAA doped combining three different dopant, we demonstrate stable PSCs with typical power conversion efficiencies above 20%, retain more than 90% of the initial efficiency after 1080 h thermal stress at 85 °C and 87% of initial efficiency after 160 h exposure against 1 sun light soaking. By using this doping-MW strategy, we realized perovskite solar modules with an efficiency of 17% on an active area of 43 cm2, keeping above 90% of the initial efficiency after 800 h thermal stress at 85 °C. These results, obtained in ambient conditions, pave the way toward the industrialization of PSC-based photovoltaic technology.</p

The future search for low-frequency axions and new physics with the FLASH resonant cavity experiment at Frascati National Laboratories

We present a proposal for a new experiment, the FINUDA magnet for Light Axion SearcH (FLASH), a large resonant-cavity haloscope in a high static magnetic field which is planned to probe new physics in the form of dark matter (DM) axions, scalar fields, chameleons, hidden photons, as well as high frequency gravitational waves (GWs). Concerning the QCD axion, FLASH will search for these particles as the DM in the mass range (0.49-1.49) ueV, thus filling the mass gap between the ranges covered by other planned searches. A dedicated Microstrip SQUID operating at ultra-cryogenic temperatures will amplify the signal. The frequency range accessible overlaps with the Very High Frequency (VHF) range of the radio wave spectrum and allows for a search in GWs in the frequency range (100-300) MHz. The experiment will make use of the cryogenic plant and magnet of the FINUDA experiment at INFN Frascati National Laboratories near Rome (Italy); the operations needed to restore the functionalities of the apparatus are currently underway. We present the setup of the experiment and the sensitivity forecasts for the detection of axions, scalar fields, chameleons, hidden photons, and GWs

Search for heavy neutral lepton production in K+ decays

A search for heavy neutral lepton production in K + decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10−7 to 10−6 level are established on the elements of the extended neutrino mixing matrix |Ue4| 2 and |Uμ4| 2 for heavy neutral lepton mass in the ranges 170–448 MeV/c2 and 250–373 MeV/c2, respectively. This improves on the previous limits from HNL production searches over the whole mass range considered for |Ue4|2 and above 300 MeV/c2 for |Uμ4|2

A Probe into the Reform of Public Calligraphy Course in Chinese Colleges and Universities

中国书法是中国传统文化中的瑰宝，它既是一门艺术，又有着深厚的文化内涵。我国普通高校开设公共书法教学是与目前倡导的素质教育，培养创新型人才，提倡人的全面和谐发展的高等教育理念相一致的。加强高校公共书法教育，是全面推进素质教育的有效途径之一，也是提高当代大学生人文素质的重要手段。它对促进大学生人格完善、创造力培养以及民族文化的传承等有着不可低估的作用。本文主要针对我国普通高等院校公共书法教学现状进行分析，并由此比较借鉴日本高校中实施书法教学的成功经验提出对我国高校公共书法教学改革的具体建议和措施，设计并实践一种具备学科视野的、以学生为主体的公共书法教学的新模式。论文共分为五部分。引言扼要介绍论文写...Chinese calligraphy is a treasure of Chinese traditional culture. It not only is an art, but also has profound culture contents. Opening the public calligraphy course to the university students is in accordance with the concept that advocated by the current quality- oriented education, which aims to cultivate the students’ creative talent and comprehensive development. This paper concentrates on a...学位：文学硕士院系专业：艺术教育学院美术系_美术学学号：20042201

Study of the K+- to pi+- gamma gamma decay by the NA62 experiment

A study of the dynamics of the rare decay $K^\pm\to\pi^\pm\gamma\gamma$ has been performed on a sample of 232 decay candidates, with an estimated background of $17.4\pm1.1$ events, collected by the NA62 experiment at CERN in 2007. The results are combined with those from a measurement conducted by the NA48/2 collaboration at CERN. The combined model-independent branching ratio in the kinematic range $z=(m_{\gamma\gamma}/m_K)^2>0.2$ is ${\cal B}_{\rm MI}(z>0.2) = (0.965 \pm 0.063) \times 10^{-6}$, and the combined branching ratio in the full kinematic range assuming a Chiral Perturbation Theory description is ${\cal B}(K_{\pi\gamma\gamma}) = (1.003 \pm 0.056) \times 10^{-6}$. A detailed comparison of the results with the previous measurements is performed.A study of the dynamics of the rare decay $K^\pm\to\pi^\pm\gamma\gamma$ has been performed on a sample of 232 decay candidates, with an estimated background of $17.4\pm1.1$ events, collected by the NA62 experiment at CERN in 2007. The results are combined with those from a measurement conducted by the NA48/2 collaboration at CERN. The combined model-independent branching ratio in the kinematic range $z=(m_{\gamma\gamma}/m_K)^2>0.2$ is ${\cal B}_{\rm MI}(z>0.2) = (0.965 \pm 0.063) \times 10^{-6}$, and the combined branching ratio in the full kinematic range assuming a Chiral Perturbation Theory description is ${\cal B}(K_{\pi\gamma\gamma}) = (1.003 \pm 0.056) \times 10^{-6}$. A detailed comparison of the results with the previous measurements is performed.A study of the dynamics of the rare decay K±→π±γγ has been performed on a sample of 232 decay candidates, with an estimated background of 17.4±1.1 events, collected by the NA62 experiment at CERN in 2007. The results are combined with those from a measurement conducted by the NA48/2 Collaboration at CERN. The combined model-independent branching ratio in the kinematic range z=(mγγ/mK)2>0.2 is BMI(z>0.2)=(0.965±0.063)×10−6 , and the combined branching ratio in the full kinematic range assuming a Chiral Perturbation Theory description is B(Kπγγ)=(1.003±0.056)×10−6 . A detailed comparison of the results with the previous measurements is performed