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organic solar cell

Shanshan Zhang, Qingfen Niu, Tao Sun, Yang Li, Tianduo Li, Haixia Liu
A novel linear A-π-D-π-A-type organic small molecule Ph2(PDPP)2 consisting diketopyrrolopyrrole (DPP) as acceptor unit, biphenylene as donor unit and acetylene unit as π-linkage has been successfully designed and synthesized. Its corresponding thermal, photophysical and electrochemical properties as well as the photoinduced charge-separation process were investigated. Ph2(PDPP)2 exhibits high thermal stability and it can be soluble in common organic solvents such as chloroform and tetrahydrofuran. The photophysical properties show that DPP2Ph2 harvests sunlight over the entire visible spectrum range in the thin-film state (300-800nm)...
April 20, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Amita Ummadisingu, Ludmilla Steier, Ji-Youn Seo, Taisuke Matsui, Antonio Abate, Wolfgang Tress, Michael Grätzel
Optimizing the morphology of metal halide perovskite films is an important way to improve the performance of solar cells when these materials are used as light harvesters, because film homogeneity is correlated with photovoltaic performance. Many device architectures and processing techniques have been explored with the aim of achieving high-performance devices, including single-step deposition, sequential deposition and anti-solvent methods. Earlier studies have looked at the influence of reaction conditions on film quality, such as the concentration of the reactants and the reaction temperature...
April 26, 2017: Nature
Nalaka P Liyanage, Hammad Cheema, Alexandra R Baumann, Alexa R Zylstra, Jared Heath Delcamp
NIR absorbing organic dyes are critically needed in dye-sensitized solar cells (DSCs). Thieno[3,4-b]pyrazine (TPz) based dyes can access the near-infrared (NIR) spectral region and show power conversion efficiencies (PCEs) of up to 8.1% with sunlight being converted at wavelengths up to 800 nm for 17.6 mA/cm2 of photocurrent in a co-sensitized DSC device. Precisely controlling dye excited-state energies is critical for good performances in NIR DSCs. Strategies to control TPz dye energetics with stronger donor groups and TPz substituent choice are evaluated in this manuscript...
April 25, 2017: ChemSusChem
Yuqin Liao, Hefei Liu, Wenjia Zhou, Dongwen Yang, Yuequn Shang, Zhifang Shi, Binghan Li, Xianyuan Jiang, Lijun Zhang, Li Na Quan, Rafael Quintero-Bermudez, Brandon R Sutherland, Qixi Mi, Edward H Sargent, Zhijun Ning
The low toxicity and a near-ideal choice of bandgap make tin (Sn) perovskite an attractive alternative to lead perovskite in low cost solar cells. However, the development of Sn perovskite solar cells has been impeded by their extremely poor stability when exposed to oxygen. We report low-dimensional Sn perovskites that exhibit markedly-enhanced air stability in comparison with their 3D counterparts. The reduced degradation under air exposure is attributed to the improved thermodynamic stability after dimensional reduction, the encapsulating organic ligands, and the compact perovskite film preventing oxygen ingress...
April 24, 2017: Journal of the American Chemical Society
Qilin Yu, Honggang Wang, Qi Peng, Ye Li, Zhe Liu, Mingchun Li
TiO2 nanoparticles (NPs) are well-known nanomaterials (NMs), widely used in cosmetics, solar cells, photo-catalysts and additives. Anatase and rutile are the two main crystalline phases of TiO2 NPs and have distinct electrical and optical properties. However, their relative toxicity to organisms is a current topic of debate. In this study, we synthesize both anatase NPs (TiO2-A) and rutile NPs (TiO2-R) with similar particle sizes (20-40nm), surface areas (51-52m(2)/g) and Zeta potentials (-13.4 to -13.7mV), and investigate their toxicity to macrophages...
April 9, 2017: Journal of Hazardous Materials
Renee Kroon, David Kiefer, Dominik Stegerer, Liyang Yu, Michael Sommer, Christian Müller
Molecular doping of organic semiconductors is critical for optimizing a range of optoelectronic devices such as field-effect transistors, solar cells, and thermoelectric generators. However, many dopant:polymer pairs suffer from poor solubility in common organic solvents, which leads to a suboptimal solid-state nanostructure and hence low electrical conductivity. A further drawback is the poor thermal stability through sublimation of the dopant. The use of oligo ethylene glycol side chains is demonstrated to significantly improve the processability of the conjugated polymer p(g4 2T-T)-a polythiophene-in polar aprotic solvents, which facilitates coprocessing of dopant:polymer pairs from the same solution at room temperature...
April 24, 2017: Advanced Materials
Stavros Athanasopoulos, Steffen Tscheuschner, Heinz Bässler, Anna Köhler
We demonstrate that efficient and nearly field-independent charge separation of electron-hole pairs in organic planar heterojunction solar cells can be described by an incoherent hopping mechanism. Using kinetic Monte Carlo simulations that include the effect of on-chain delocalization as well as entropic contributions, we simulate the dissociation of the charge-transfer state in polymer-fullerene bilayer solar cells. The model further explains experimental results of almost field independent charge separation in bilayers of molecular systems with fullerenes and provides important guidelines at the molecular level for maximizing the efficiencies of organic solar cells...
April 26, 2017: Journal of Physical Chemistry Letters
Yiying Li, Peicheng Li, Zheng-Hong Lu
An organic semiconductor thin film is a solid-state matter comprising one or more molecules. For applications in electronics and photonics, several distinct functional organic thin films are stacked together to create a variety of devices such as organic light-emitting diodes and organic solar cells. The energy levels at these thin-film junctions dictate various electronic processes such as the charge transport across these junctions, the exciton dissociation rates at donor-acceptor molecular interfaces, and the charge trapping during exciton formation in a host-dopant system...
April 24, 2017: Advanced Materials
Lukas Kegelmann, Christian M Wolff, Celline Awino Omondi, Felix Lang, Eva Lisa Unger, Lars Korte, Thomas Dittrich, Dieter Neher, Bernd Rech, Steve Albrecht
Solar cells made from inorganic-organic perovskites gradually approach market requirements as efficiency and stability improved tremendously in recent years. Planar low-temperature processed perovskite solar cells are advantageous for a possible large-scale production but are more prone to exhibit photocurrent hysteresis, especially in the regular n-i-p structure. Here, a systematic characterization of different electron selective contacts with a variety of chemical and electrical properties in planar n-i-p devices processed below 180 °C is presented...
April 24, 2017: ACS Applied Materials & Interfaces
Tianqi Lai, Xuebin Chen, Liangang Xiao, Lin Zhang, Tianxiang Liang, Xiaobin Peng, Yong Cao
Three conjugated D-A porphyrin dimers (DPP-ZnP-E)2, (DPP-ZnP-E)2-2T and (DPP-ZnP-E)2-Ph linked with diethynylene, diethynylene-dithiophene and diethynylene-phenylene have been developed for bulk heterojunction solar cells with high power conversion efficiencies of 4.50%, 5.50% and 6.42%, respectively, when blended with PC61BM as the electron acceptor material.
April 24, 2017: Chemical Communications: Chem Comm
Meng-Lin Tsai, Dung-Sheng Tsai, Libin Tang, Lih-Juann Chen, Shu Ping Lau, Jr-Hau He
Despite great improvements in traditional inorganic photodetectors and photovoltaics, more progress is needed in the detection/collection of light at low-level conditions. Traditional photodetectors tend to suffer from high noise when operated at room temperature; therefore these devices require additional cooling systems to detect weak or dim light. Conventional solar cells also face the challenge of poor light-harvesting capabilities in hazy or cloudy weather. The real world features such varying levels of light, which makes it important to develop strategies that allow optical devices to function when conditions are less than optimal...
April 21, 2017: ACS Nano
Shiuh-Chuan Her, Chun-Fu Chang
BACKGROUND: Transparent conducting oxide (TCO) films are of particular interest in the field of optoelectronics, due to the requirement for transparent electrodes in applications such as organic light-emitting diodes, solar cells and so on. The aim of this study was to obtain a better understanding of the effects of preparation temperature on indium tin oxide (ITO) films, to improve their performance for optoelectronic applications. METHODS: ITO films were deposited on glass substrate at different temperatures, using direct current (DC) magnetron sputtering...
April 5, 2017: Journal of Applied Biomaterials & Functional Materials
Yingguo Yang, Shanglei Feng, Meng Li, Weidong Xu, Guangzhi Yin, Zhaokui Wang, Baoquan Sun, Xingyu Gao
Using poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as hole conductor, a series of inverted planar CH3NH3PbI3-xClx perovskite solar cells (PSCs) were fabricated based on perovskite annealed by an improved time-temperature dependent (TTD) procedure in a flowing nitrogen atmosphere for different time. Only after an optimum annealing time, an optimized power conversion efficiency of 14.36% could be achieved. To understand their performance dependence on annealing time, an in situ real-time synchrotron-based grazing incidence X-ray diffraction (GIXRD) was used to monitor a step-by-step gradual structure transformation from distinct mainly organic-inorganic hybrid materials into highly ordered CH3NH3PbI3 crystal during annealing...
April 21, 2017: Scientific Reports
Ziang Xie, Shuren Sun, Yu Yan, Lili Zhang, Ruixiang Hou, Fuyang Tian, Guogang Qin
Very recently, the NH2CH=NH2PbI3 (FAPbI3) perovskite material has attracted much attention in fabricating solar cells (SCs). For a photovoltaic material, its refractive index and extinction coefficient, n(λ) and k(λ), as functions of λ, are important to study its optical properties and to estimate the power conversion efficiency potential for the SCs made of it. As far as we know, so far there is no reporting of n(λ) and k(λ) for the FAPbI3 material. In this article, with spectroscopic ellipsometry (SE) measurements, the n(λ) and k(λ), as well as Eg = 1...
April 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Wenjun Wu, Huaide Xiang, Wei Fan, Jinglin Wang, Haifeng Wang, Xin Hua, Zhaohui Wang, Yi-Tao Long, He Tian, Wei-Hong Zhu
Up to date, development of organic sensitizers has been predominately focused on light harvesting, HOMO and LUMO energy levels, and electron transferring process. In contrast, their adsorption mode as well as dynamic loading behaviour onto nanoporous TiO2 is rarely considered. Herein we have employed the time of flight secondary ion mass spectrometry (TOF-SIMS) to take insight into the competitive dye adsorption mode and kinetics in cosensitized porphyrin system. Using the novel porphyrin dye FW-1 and D-A-π-A featured dye WS-5, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well compared with two different anchoring groups such as benzoic acid and cyanoacrylic acid...
April 20, 2017: ACS Applied Materials & Interfaces
Jin-Wook Lee, Yao-Tsung Hsieh, Nicholas De Marco, Sang-Hoon Bae, Qifeng Han, Yang Yang
Perovskite solar cells have become one of the strongest candidates for next-generation solar energy technologies. A myriad of beneficial optoelectronic properties of the perovskite materials have enabled superb power conversion efficiencies (PCE) exceeding 22% for a single-junction device. The high PCE achievable via low processing costs and relatively high variability in optical properties have opened new possibilities for perovskites in tandem solar cells. In this Perspective, we will discuss current research trends in fabricating tandem perovskite-based solar cells in combination with a variety of mature photovoltaic devices such as organic, silicon, and Cu(In,Ga)(S,Se)2 (CIGS) solar cells...
April 24, 2017: Journal of Physical Chemistry Letters
Dong Meng, Huiting Fu, Bingbing Fan, Jianqi Zhang, Yan Li, Yanming Sun, Zhaohui Wang
Three kinds of non-conjugated rigid perylene bisimide (PBI) derivatives based on a triptycene core were designed, synthesized and characterized. The unique three-dimensional (3D) conformation of triptycene could enable formation of polymer with the favorable morphology for organic polymer solar cells (PSCs) by relieving the self-aggregation of rigid PBI units. The low-lying LUMO energy levels of these compounds demonstrated that they are very suitable for using as acceptors in organic solar cells. A higher power conversion efficiency (PCE) of 6...
April 19, 2017: Chemistry, An Asian Journal
Sharareh Izadnia, David Schönleber, Alexander Eisfeld, Alex Ruf, Aaron C LaForge, Frank Stienkemeier
The energy conversion in solar cells has conventionally been limited by the Shockley-Queisser limit. Singlet fission (SF), a decay mechanism where a single excited singlet state is converted into two triplet states, can drastically improve this efficiency. For the most part, observation of SF has been limited to crystalline structures in solids and films, where strong ordering was present. Here, we report on singlet fission in a disordered system where organic chromophores are distributed on the surface of a rare gas cluster...
April 19, 2017: Journal of Physical Chemistry Letters
Thomas J Sisto, Yu Zhong, Boyuan Zhang, M Tuan Trinh, Kiyoshi Miyata, Xinjue Zhong, X-Y Zhu, Michael L Steigerwald, Fay Ng, Colin Nuckolls
This Communication describes a new molecular design for the efficient synthesis of donor-acceptor, cove-edge graphene nanoribbons and their properties in solar cells. These nanoribbons are long (∼5 nm), atomically precise, and soluble. The design is based on the fusion of electron deficient perylene diimide oligomers with an electron rich alkoxy pyrene subunit. This strategy of alternating electron rich and electron poor units facilitates a visible light fusion reaction in >95% yield, whereas the cove-edge nature of these nanoribbons results in a high degree of twisting along the long axis...
April 18, 2017: Journal of the American Chemical Society
Dong Hoe Kim, Jaehong Park, Zhen Li, Mengjin Yang, Ji-Sang Park, Ik Jae Park, Jin Young Kim, Joseph J Berry, Garry Rumbles, Kai Zhu
Organic-inorganic perovskites with intriguing optical and electrical properties have attracted significant research interests due to their excellent performance in optoelectronic devices. Recent efforts on preparing uniform and large-grain polycrystalline perovskite films have led to enhanced carrier lifetime up to several microseconds. However, the mobility and trap densities of polycrystalline perovskite films are still significantly behind their single-crystal counterparts. Here, a facile topotactic-oriented attachment (TOA) process to grow highly oriented perovskite films, featuring strong uniaxial-crystallographic texture, micrometer-grain morphology, high crystallinity, low trap density (≈4 × 10(14) cm(-3) ), and unprecedented 9 GHz charge-carrier mobility (71 cm(2) V(-1) s(-1) ), is demonstrated...
April 18, 2017: Advanced Materials
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