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Wenjin Zeng, Xingming Liu, Xiangru Guo, Qiaoli Niu, Jianpeng Yi, Ruidong Xia, Yong Min
This review presents an overall discussion on the morphology analysis and optimization for perovskite (PVSK) solar cells. Surface morphology and energy alignment have been proven to play a dominant role in determining the device performance. The effect of the key parameters such as solution condition and preparation atmosphere on the crystallization of PVSK, the characterization of surface morphology and interface distribution in the perovskite layer is discussed in detail. Furthermore, the analysis of interface energy level alignment by using X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy is presented to reveals the correlation between morphology and charge generation and collection within the perovskite layer, and its influence on the device performance...
March 24, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Patrick Steiger, Renaud Delmelle, Debora Foppiano, Lorenz Holzer, Andre Heel, Maarten Nachtegaal, Oliver Kröcher, Davide Ferri
Perovskite-type oxides have shown the ability to reversibly segregate precious metals from their structure. This reversible segregation behavior was explored for a commonly used catalyst metal, Ni, to prevent Ni sintering, which is observed on most catalyst support materials. TPR, XRD, XAS, electron microscopy and catalytic activity tests were used to follow the extent of reversible Ni segregation. LaFe1 xNixO3±δ (0 ≤ x ≤ 0.2) was synthesized using a citrate based solution process. After reduction at 600°C metallic Ni particles were displayed on the perovskite surfaces, which showed to be active towards the hydrogenation of CO2...
March 24, 2017: ChemSusChem
F Pelayo García de Arquer, Xiwen Gong, Randy P Sabatini, Min Liu, Gi-Hwan Kim, Brandon R Sutherland, Oleksandr Voznyy, Jixian Xu, Yuangjie Pang, Sjoerd Hoogland, David Sinton, Edward Sargent
Quantum dot and well architectures are attractive for infrared optoelectronics, and have led to the realization of compelling light sensors. However, they require well-defined passivated interfaces and rapid charge transport, and this has restricted their efficient implementation to costly vacuum-epitaxially grown semiconductors. Here we report solution-processed, sensitive infrared field-emission photodetectors. Using quantum-dots-in-perovskite, we demonstrate the extraction of photocarriers via field emission, followed by the recirculation of photogenerated carriers...
March 24, 2017: Nature Communications
Qi Chen, Lei Chen, Fengye Ye, Ting Zhao, Feng Tang, Adharsh Rajagopal, Zheng Jiang, Shenlong Jiang, Alex K-Y Jen, Yi Xie, Jinhua Cai, Liwei Chen
Controlled doping for adjustable material polarity and charge carrier concentration is the basis of semiconductor materials and devices, and it is much more difficult to achieve in ionic semiconductors (e.g. ZnO and GaN) than in covalent semiconductors (e.g. Si and Ge), due to the high intrinsic defect density in ionic semiconductors. The organic-inorganic perovskite material, which is frenetically being researched for applications in solar cells and beyond, is also an ionic semiconductor. Here we present the Ag-incorporated organic-inorganic perovskite films and planar heterojunction solar cells...
March 24, 2017: Nano Letters
Phil Szuromi
No abstract text is available yet for this article.
March 24, 2017: Science
Osman M Bakr, Omar F Mohammed
No abstract text is available yet for this article.
March 24, 2017: Science
Aibin Huang, Lei Lei, Jingting Zhu, Yu Yu, Yan Liu, Songwang Yang, Shanhu Bao, Xun Cao, Ping Jin
Aiming at fabricating simple, reproducible and scalable perovskite solar cells (PSCs) with least time consuming, novel CoOx hole transport layer (HTL) was first proposed and introduced in this work. The CoOx HTL thickness was minimized to about 10 nm with complete coverage on FTO substrate (F doped SnO2) by DC magnetron sputtering. The compact ultrathin HTL could minimize the incident light loss caused by cobalt ion absorption and reduce the carrier transport loss by shortening the transport path. Copper ion doping was employed to address the low conductivity of CoOx film and the energy level mismatch between CoOx and perovskite material...
March 23, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Lung-Chien Chen, Zong-Liang Tseng, Jun-Kai Huang
This work presents mixed (FAPbI₃)1-x(MAPbBr₃)x perovskite films with various composition ratios, x (x = 0-1), which are formed using the spin coating method. The structural, optical, and electronic behaviors of the mixed (FAPbI₃)1-x(MAPbBr₃)x perovskite films are discussed. A device with structure glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/mixed perovskite/C60/BCP/Ag was fabricated. The mixed perovskite film was an active light-harvesting layer. PEDOT: PSS was a hole transporting layer between the ITO and perovskite...
October 13, 2016: Nanomaterials
Chih-Yu Chang, Bo-Chou Tsai, Yu-Cheng Hsiao
In this work, efficient and stable vacuum-free processed perovskite solar cells (PeSCs) is demonstrated by employ solution-processed molybdenum tris-[1-(trifluoroethanoyl)-2-(trifluoromethyl)ethane-1,2-dithiolene] (Mo(tfd-COCF3)3)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) film as hole transport layer (HTL). Our results indicate that the incorporation of Mo(tfd-COCF3)3 dopant can induce p-doping via the charge transfer from the highest occupied molecular orbital level of PEDOT host to the electron affinity of Mo(tfd-COCF3)3, leading to an increase in conductivity by more than three orders of magnitude...
March 23, 2017: ChemSusChem
Lianfeng Zhao, Yao-Wen Yeh, Nhu L Tran, Fan Wu, Zhengguo Xiao, Ross A Kerner, YunHui L Lin, Gregory D Scholes, Nan Yao, Barry P Rand
Hybrid organic-inorganic halide perovskite semiconductors are attractive candidates for optoelectronic applications, such as photovoltaics, light-emitting diodes, and lasers. Perovskite nanocrystals are of particular interest, where electrons and holes can be confined spatially, promoting radiative recombination. However, nanocrystalline films based on traditional colloidal nanocrystal synthesis strategies suffer from the use of long insulating ligands, low colloidal nanocrystal concentration, and significant aggregation during film formation...
March 23, 2017: ACS Nano
Markus Pichler, Jakub Szlachetko, Ivano Eligio Castelli, Nicola Marzari, Max Döbeli, Alexander Wokaun, Daniele Pergolesi, Thomas Lippert
The nitrogen substitution into the oxygen sites of several oxide materials leads to a reduction of the band gap to the visible light energy range, which makes these oxynitride semiconductors potential photocatalysts for efficient solar water splitting. Oxynitrides typically show a different crystal structure compare to the pristine oxide material. Since the band gap is correlated to both the chemical composition and the crystal structure, it is not trivial to distinguish what modifications of the electronic structure induced by the nitrogen substitution are related to compositional and/or structural effects...
March 23, 2017: ChemSusChem
Xingxing Xiao, Marc Widenmeyer, Wenjie Xie, Tianhua Zou, Songhak Yoon, Marco Scavini, Stefano Checchia, Zhicheng Zhong, Philipp Hansmann, Stefan Kilper, Andrei Kovalevsky, Anke Weidenkaff
A series of Ba1-xEuxTiO3-δ (0.1 ≤ x ≤ 0.9) phases with ∼40 nm particle size were synthesized via a Pechini method followed by annealing and sintering under a reducing atmosphere. The effects of Eu(2+) substitution on the BaTiO3 crystal structure and the thermoelectric transport properties were systematically investigated. According to synchrotron X-ray diffraction data only cubic perovskite structures were observed. On the local scale below about 20 Å (equal to ∼5 unit cells) deviations from the cubic structure model (Pm3[combining macron]m) were detected by evaluation of the pair distribution function (PDF)...
March 23, 2017: Physical Chemistry Chemical Physics: PCCP
Jinmiao Wang, Zhao-Kui Wang, Meng Li, Ke-Hao Hu, Yingguo Yang, Yun Hu, Xingyu Gao, Liang-Sheng Liao
Effective and stable hole-transporting materials (HTMs) are necessary for obtaining excellent planar perovskite solar cells (PSCs). Herein, we reported a solution-processed composite HTM consisting of a polymer ploy(3,4-ethylene-dioxythiophene):ploystyrenesulfonate (PEDOT:PSS) and a small molecule copper phthalocyanine-3,4',4'',4'''-tetra-sulfonated acid tetra sodium salt (TS-CuPc) with optimized doping ratios. The composite HTM is crucial on account of not only enhancing the hole transport and extraction, but also improving the perovskite crystallization...
March 23, 2017: ACS Applied Materials & Interfaces
Zhi-Yuan Zhu, Qi-Qi Yang, Lin-Feng Gao, Lei Zhang, An-Ye Shi, Chun-Lin Sun, Qiang Wang, Hao-Li Zhang
A facile and green mechanosynthesis strategy free of solvent and high reaction temperature was developed to fabricate highly emissive cesium lead halide perovskite (CsPbX3) quantum dots (QDs). Their composition can be adjusted conveniently simply through mechanically milling/grinding stoichiometric combinations of raw reagents, thereby introducing a broad luminescence tunability of the product with adjustable wavelength, linewidth and photoluminescence quantum yield. Desired CsPbX3 QDs "library" can thus be readily constructed in a way like assembling Lego building blocks...
March 22, 2017: Journal of Physical Chemistry Letters
Dayton Jon Vogel, Andrei Kryjevski, Talgat M Inerbaev, Dmitri S Kilin
Methyl-ammonium lead iodide perovskite (MAPbI3) is a promising material for photovoltaic devices. A modification of the MAPbI3 into confined nanostructures is expected to further increase efficiency of solar energy conversion. Photo-excited dynamic processes in a MAPbI3 quantum dot (QD) have been modeled by many-body perturbation theory and nonadiabatic dynamics. A photoexcitation is followed by either exciton cooling (EC), its radiative (RR) or non-radiative recombination (NRR), or multi-exciton generation (MEG) processes...
March 21, 2017: Journal of Physical Chemistry Letters
Luisa Ariza-Carmona, Gonzalo García-Espejo, María T Martín-Romero, Luis Camacho
The present work studies the stability of Langmuir organic-inorganic superlattice materials thin films consisting of layered perovskite-based films with controlled 2D framework as well as to design experimental conditions for increasing the efficiency of the organic-inorganic perovskite motif by mechanical stimulus. Therefore, a whole covering of the air/water interface by a compact and stable lead-based layered perovskite structure is pursued. A 2D layered perovskite-type hybrid structure of the form [(CH3(CH2)19NH3)2(PbX4)], X=Cl, and Br, in which, two-dimensional sheets stabilized by a inner bilayer of organic monoammonium cation matrix, is mechanically tailored by successive compression-expansion cycles...
March 14, 2017: Journal of Colloid and Interface Science
Lyubov A Frolova, Denis V Anokhin, Alexey A Piryazev, Sergey Yurevich Luchkin, Nadezhda N Dremova, Pavel A Troshin
We present all-inorganic photoactive material composed of Ag2PbI4 and PbI2, which shows unexpectedly good photovoltaic performance in planar junction solar cells delivering the external quantum efficiencies of ~60% and light power conversion efficiencies of ~3.9%. The revealed characteristics are among the best reported so far for metal halides with non-perovskite crystal structure. This result highlights a big potential of further exploration of this family of compounds aimed at the development of new generation of materials for efficient and sustainable photovoltaic technologies...
March 21, 2017: Journal of Physical Chemistry Letters
Heejae Chung, Seok Il Jung, Hyo Jin Kim, Wonhee Cha, Eunji Sim, Dongho Kim, Weon-Kyu Koh, Jiwon Kim
Cesium-based perovskite nanocrystals (NCs) have outstanding photophysical properties improving the performances of lighting devices. Fundamental studies on excitonic properties and hot-carrier dynamics in perovskite NCs further suggest that these materials show higher efficiencies compared to the bulk form of perovskites. However, the relaxation rates and pathways of hot-carriers are still being elucidated. By using ultrafast transient spectroscopy and calculating electronic band structures, we investigated the dependence of halide in Cs-based perovskite (CsPbX3 with X=Br, I, or their mixtures) NCs on the hot-carrier relaxation processes...
March 20, 2017: Angewandte Chemie
Yoshiteru Hosaka, Fabio Denis Romero, Noriya Ichikawa, Takashi Saito, Yuichi Shimakawa
A perovskite-structure oxide containing unusually high-valence Fe(3.5+) was obtained by high-pressure synthesis. Instability of the Fe(3.5+) in Ca0.5 Bi0.5 FeO3 is relieved first by charge disproportionation at 250 K and then by intermetallic charge transfer between A-site Bi and B-site Fe at 200 K. These previously unobserved successive charge transitions are due to competing intermetallic and disproportionation charge instabilities. Both transitions change magnetic and structural properties significantly, indicating strong coupling of charge, spin, and lattice in the present system...
March 20, 2017: Angewandte Chemie
Abdullah Al Mamun, Tanzila Tasnim Ava, Hyeon Jun Jeong, Mun Seok Jeong, Gon Namkoong
We explore a new characterization approach capable of probing the grain interior (GI) and grain boundary (GB) of a CH3NH3PbI3-xClx perovskite thin film. In particular, we have found that the photoluminescence (PL) spectrum observed for a CH3NH3PbI3-xClx perovskite thin film is asymmetric, and can be deconvoluted using a bi-Gaussian function, representing the ordered and disordered phases of the perovskite film. In order to understand the origin of the ordered and disordered phases of the perovskite film, two-dimensional (2D) PL mapping was performed to resolve the PL spectra at the nanoscale level...
March 20, 2017: Physical Chemistry Chemical Physics: PCCP
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