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organic photovoltaic

Christian Hintze, Tobias O Morgen, Malte Drescher
In several fields of research, like e.g. photosensitization, photovoltaics, organic electroluminescent devices, dynamic nuclear polarization, or pulsed dipolar electron paramagnetic resonance spectroscopy, triplet state kinetics play an important role. It is therefore desirable to tailor the kinetics of photoexcited triplet states, e.g. by exploiting the intramolecular heavy-atom effect, and to determine the respective kinetic parameters. In this work, we set out to systematically investigate the photoexcited triplet state kinetics of a series of haloanthracenes by time-resolved electron paramagnetic resonance spectroscopy in combination with synchronized laser excitation...
2017: PloS One
Xujie Lü, Wenge Yang, Quanxi Jia, Hongwu Xu
Organic-inorganic halide perovskites have emerged as a promising family of functional materials for advanced photovoltaic and optoelectronic applications with high performances and low costs. Various chemical methods and processing approaches have been employed to modify the compositions, structures, morphologies, and electronic properties of hybrid perovskites. However, challenges still remain in terms of their stability, the use of environmentally unfriendly chemicals, and the lack of an insightful understanding into structure-property relationships...
October 1, 2017: Chemical Science
Yongxi Li, Jiu-Dong Lin, Xiaozhou Che, Yue Qu, Feng Liu, Liang-Sheng Liao, Stephen R Forrest
The absence of near-infrared (NIR) solar cells with high open circuit voltage (Voc) and external quantum efficiency (EQE) has impeded progress toward achieving organic photovoltaic (OPV) power conversion efficiency PCE > 15%. Here we report a small energy gap (1.3 eV), chlorinated nonfullerene acceptor-based solar cell with PCE = 11.2 ± 0.4%, short circuit current of 22.5 ± 0.6 mA cm(-2), Voc = 0.70 ± 0.01 V and fill factor of 0.71 ± 0.02, which is the highest performance reported to date for NIR single junction OPVs...
November 16, 2017: Journal of the American Chemical Society
Zhibin Yang, Adharsh Rajagopal, Alex K-Y Jen
Extremely high power conversion efficiencies (PCEs) of ≈20-22% are realized through intensive research and development of 1.5-1.6 eV bandgap perovskite absorbers. However, development of ideal bandgap (1.3-1.4 eV) absorbers is pivotal to further improve PCE of single junction perovskite solar cells (PVSCs) because of a better balance between absorption loss of sub-bandgap photons and thermalization loss of above-bandgap photons as demonstrated by the Shockley-Queisser detailed balanced calculation. Ideal bandgap PVSCs are currently hindered by the poor optoelectronic quality of perovskite absorbers and their PCEs have stagnated at <15%...
November 14, 2017: Advanced Materials
Anantaya Lertngim, Manisara Phiriyawirut, Jatuphorn Wootthikanokkhan, Kitti Yuwawech, Weradesh Sangkhun, Pisist Kumnorkaew, Tanyakorn Muangnapoh
This research concerns the development of Surlyn film reinforced with micro-/nanofibrillated celluloses (MFC) for use as an encapsulant in organic photovoltaic (OPV) cells. The aim of this work was to investigate the effects of fibre types and the mixing methods on the structure-properties of the composite films. Three types of cellulose micro/nanofibrils were prepared: the as-received MFC, the dispersed MFC and the esterified MFC. The fibres were mixed with Surlyn via an extrusion process, using two different mixing methods...
October 2017: Royal Society Open Science
Zubair Ahmad, Mansoor Ani Najeeb, R A Shakoor, Abdulla Alashraf, Shaheen A Al-Muhtaseb, Ahmed Soliman, M K Nazeeruddin
Organic-inorganic halide perovskites have rapidly grown as favorable materials for photovoltaic applications, but accomplishing long-term stability is still a major research problem. This work demonstrates a new insight on instability and degradation factors in CH3NH3PbI3 perovskite solar cells aging with time in open air. X-ray photoelectron spectroscopy (XPS) has been used to investigate the compositional changes caused by device degradation over the period of 1000 hrs. XPS spectra confirm the migration of metallic ions from the bottom electrode (ITO) as a key factor causing the chemical composition change in the perovskite layer besides the diffusion of oxygen...
November 13, 2017: Scientific Reports
Ke Gao, Zonglong Zhu, Bo Xu, Sae Byeok Jo, Yuanyuan Kan, Xiaobin Peng, Alex K-Y Jen
Employing a layer of bulk-heterojunction (BHJ) organic semiconductors on top of perovskite to further extend its photoresponse is considered as a simple and promising way to enhance the efficiency of perovskite-based solar cells, instead of using tandem devices or near infrared (NIR)-absorbing Sn-containing perovskites. However, the progress made from this approach is quite limited because very few such hybrid solar cells can simultaneously show high short-circuit current (JSC ) and fill factor (FF). To find an appropriate NIR-absorbing BHJ is essential for highly efficient, organic, photovoltaics (OPV)/perovskite hybrid solar cells...
November 13, 2017: Advanced Materials
Yu-Tang Hsiao, Chia-Hua Li, Shao-Ling Chang, Soowon Heo, Keisuke Tajima, Yen-Ju Cheng, Chain-Shu Hsu
In this research, a haptacyclic carbazole-based dithienocyclopentacarbazole (DTCC) ladder-type structure was formylated to couple with two 1,1-dicyanomethylene-3-indanone (IC) moieties, forming a new non-fullerene acceptor DTCCIC-C17 using a bulky branched 1-octylnonayl side chain at the nitrogen of the embedded carbazole and four 4-octylphenyl groups at the sp3-carbon bridges. The rigid and coplanar main-chain backbone of DTCC core provides a broad light-absorbing window and a higher-lying LUMO energy level, while the bulky flanked side chains to reduce intermolecular interactions make DTCCIC-C17 amorphous with excellent solution processability...
November 10, 2017: ACS Applied Materials & Interfaces
Ik Jae Park, Seongrok Seo, Min Ah Park, Sangwook Lee, Dong Hoe Kim, Kai Zhu, Hyunjung Shin, Jin Young Kim
We report the electrical properties of rubidium-incorporated methylammonium lead iodide ((RbxMA1-x)PbI3) films and the photovoltaic performance of (RbxMA1-x)PbI3 film-based p-i-n-type perovskite solar cells (PSCs). The incorporation of a small amount of Rb(+) (x = 0.05) increases both the open circuit voltage (Voc) and the short circuit photocurrent density (Jsc) of the PSCs, leading to an improved power conversion efficiency (PCE). However, a high fraction of Rb(+) incorporation (x = 0.1 and 0.2) decreases the Jsc and thus the PCE, which is attributed to the phase segregation of the single tetragonal perovskite phase to a MA-rich tetragonal perovskite phase and a RbPbI3 orthorhombic phase at high Rb fractions...
November 20, 2017: ACS Applied Materials & Interfaces
Lu-Yao Wang, Lin-Long Deng, Xin Wang, Tan Wang, Hao-Ran Liu, Si-Min Dai, Zhou Xing, Su-Yuan Xie, Rong-Bin Huang, Lan-Sun Zheng
Organic-inorganic perovskite solar cells have emerged as a promising photovoltaic technology because of their advantages such as low cost, high efficiency, and solution processability. The performance of perovskite solar cells is highly dependent on the crystallinity and morphology of the perovskite films. Herein, we report a simple, one-step anti-solvent deposition process using di-isopropyl ether as a dripping solvent to obtain extremely uniform and highly crystalline CH3NH3PbI3 perovskite films. Compared to toluene, chlorobenzene, chloroform, or diethyl ether, di-isopropyl ether has proven to be a more suitable solvent for an anti-solvent deposition process...
November 9, 2017: Nanoscale
Szymon Chorazy, Maciej Wyczesany, Barbara Sieklucka
Solid-state functional luminescent materials arouse an enormous scientific interest due to their diverse applications in lighting, display devices, photonics, optical communication, low energy scintillation, optical storage, light conversion, or photovoltaics. Among all types of solid luminophors, the emissive coordination polymers, especially those based on luminescent trivalent lanthanide ions, exhibit a particularly large scope of light-emitting functionalities, fruitfully investigated in the aspects of chemical sensing, display devices, and bioimaging...
November 4, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Christopher Grieco, Eric R Kennehan, Adam Rimshaw, Marcia M Payne, John E Anthony, John B Asbury
Ultrafast vibrational spectroscopy in the mid-infrared spectral range provides the opportunity to probe the dynamics of electronic states involved in all stages of the singlet fission reaction through their unique vibrational frequencies. This capability is demonstrated using a model singlet fission chromophore, 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn). The alkyne groups of the TIPS side chains are coupled to the conjugated framework of the pentacene cores, enabling direct examination of the dynamics of triplet excitons that have successfully separated from correlated triplet pair states in crystalline films of TIPS-Pn...
November 9, 2017: Journal of Physical Chemistry Letters
Samuel J Hein, Dan Lehnherr, Hasan Arslan, Fernando J Uribe-Romo, William R Dichtel
Aromatic compounds and polymers are integrated into organic field effect transistors, light-emitting diodes, photovoltaic devices, and redox-flow batteries. These compounds and materials feature increasingly complex designs, and substituents influence energy levels, bandgaps, solution conformation, and crystal packing, all of which impact performance. However, many polycyclic aromatic hydrocarbons of interest are difficult to prepare because their substitution patterns lie outside the scope of current synthetic methods, as strategies for functionalizing benzene are often unselective when applied to naphthalene or larger systems...
November 7, 2017: Accounts of Chemical Research
Yuchuan Shao, Ye Liu, Xiaolong Chen, Chen Chen, Ibrahim Sarpkaya, Zhaolai Chen, Yanjun Fang, Jaemin Kong, Kenji Watanabe, Takashi Taniguchi, Andre D Taylor, Jinsong Huang, Fengnian Xia
Recently two dimensional (2D) organic-inorganic perovskites emerge as an alternative material for their 3D counterparts in photovoltaic applications with improved moisture resistance. Here, we report a stable, high-gain phototransistor consisting of a monolayer graphene on hexagonal boron nitride (hBN) covered by a 2D multiphase perovskite heterostructure, which was realized using a newly developed two-step ligand exchange method. In this phototransistor, the multiple phases with varying bandgap in 2D perovskite thin films are aligned for the efficient electron-hole pair separation, leading to a high responsivity of ~10(5) A W(-1) at 532 nm...
November 7, 2017: Nano Letters
Zhenhai Yang, Zhaolang Liu, Jiang Sheng, Wei Guo, Yuheng Zeng, Pingqi Gao, Jichun Ye
Recently, silicon single nanowire solar cells (SNSCs) serving as the sustainable self-power sources have been integrated into optoelectronic nanodevices under the driver of technology and economy. However, conventional SNSC cannot provide the minimum energy consumption for the operation of nanodevices due to its low power conversion efficiency (PCE). Here, we propose an innovative approach to combine the n-type silicon nanowires (SiNWs) with p-type poly(3,4-ethylthiophene):poly(styrenesulfonate) (PEDOT:PSS) to form the p (+) n heterojunction, which shows superior opto-electric performances...
November 6, 2017: Scientific Reports
María C Gélvez-Rueda, Nicolas Renaud, Ferdinand C Grozema
The fundamental opto-electronic properties of organic-inorganic hybrid perovskites are strongly affected by their structural parameters. These parameters are particularly critical in formamidinium lead iodide (FAPbI3), in which its large structural disorder leads to a non-perovskite yellow phase that hinders its photovoltaic performance. A clear understanding of how the structural parameters affect the opto-electronic properties is currently lacking. We have studied the opto-electronic properties of FAPbI3 using microwave conductivity measurements...
October 26, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Huanqing Ye, Viktor Bogdanov, Sheng Liu, Saumitra Vajandar, Thomas Osipowicz, Ignacio Hernandez, Qihua Xiong
Converting low-energy photons via thermal radiation can be a potential approach to utilizing IR photons to improve photovoltaic efficiency. Lanthanide-containing materials have achieved great progress in IR to visible photon upconversion (UC). Herein, we firstly report bright photon, tunable wavelength UC through localized thermal radiation at the molecular scale with low excitation power density (< 10 W/cm2) realized on lanthanide complexes of perfluorinated organic ligands. This is enabled by engineering the pathways of nonradiative de-excitation and energy transfer in a composite of ytterbium and terbium perfluoroimidodiphosphinates...
November 3, 2017: Journal of Physical Chemistry Letters
Kui Huang, Kang Lai, Chang-Lin Yan, Wei-Bing Zhang
Recently, atomically thin organic-inorganic hybrid perovskites have been synthesized experimentally, which opens up new opportunities for exploring their novel properties in the 2D limit. Based on the comparative density functional theory calculation with and without spin-orbit coupling effects, the stability, electronic structure, and carrier mobility of the two-dimensional organic-inorganic hybrid perovskites MAPbI3 (MA = CH3NH3) have been investigated systemically. Two single-unit-cell-thick 2D MAPbI3 terminated by PbI2 and CH3NH3I are constructed, and their thermodynamic stabilities are also evaluated using the first-principles constrained thermodynamics method...
October 28, 2017: Journal of Chemical Physics
Douglas H Fabini, Ting Ann Siaw, Constantinos C Stoumpos, Geneva Laurita, Daniel Olds, Katharine Page, Jerry G Hu, Mercouri G Kanatzidis, Songi Han, Ram Seshadri
The role of organic molecular cations in the high-performance perovskite photovoltaic absorbers, methylammonium lead iodide (MAPbI3) and formamidinium lead iodide (FAPbI3), has been an enigmatic subject of great interest. Beyond aiding in the ease of processing of thin films for photovoltaic devices, there have been suggestions that many of the remarkable properties of the halide perovskites can be attributed to the dipolar nature and the dynamic behavior of these cations. Here, we establish the dynamics of the molecular cations in FAPbI3 between 4 K and 340 K and the nature of their interaction with the surrounding inorganic cage using a combination of solid state nuclear magnetic resonance and dielectric spectroscopies, neutron scattering, calorimetry, and ab initio calculations...
November 2, 2017: Journal of the American Chemical Society
Dong Young Chung, Yoon Jun Son, Ji Mun Yoo, Jin Soo Kang, Chi-Yeong Ahn, Subin Park, Yung-Eun Sung
Nitrogen-doped porous carbon materials have been highlighted as promising alternatives to high-cost platinum in various electrochemical energy applications. However, protocols to generate effective pore structure are still challenging, which hampers mass production and utilization of carbon materials. Here, we suggest a facile and effective method for hierarchical porous carbon by a single-step carbonization of coffee waste (CW) with ZnCl2. The CW, which is one of the most earth-abundant organic waste, can be successfully converted to nitrogen-doped porous carbon...
November 14, 2017: ACS Applied Materials & Interfaces
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