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organic photovoltaic

Yaohong Zhang, Guohua Wu, Ivan Mora-Sero, Chao Ding, Feng Liu, Qingxun Huang, Yuhei Ogomi, Shuzi Hayase, Taro Toyoda, Ruixiang Wang, Joe Otsuki, Qing Shen
A novel organic small molecule bis-triphenylamine with spiro(fluorene-9,9'-xanthene) as the conjugated system, named BTPA-4, is successfully synthesized and employed as the hole-selective layer (HSL) in colloidal quantum dots solar cells (CQDSCs). The introduction of BTPA-4 layer can significantly prolong effective carrier lifetime (τeff), increase charge recombination resistance (Rrec), and thus diminish the interfacial charge recombination at the PbS-QDs/Au electrode interface. The effect of BTPA-4 as HSL in the device performance is especially significant for the open-circuit voltage (Voc) and power conversion efficiency (PCE), with a ~ 10% and 15% enhancement respectively, comparing with those of device without the HSL...
April 27, 2017: Journal of Physical Chemistry Letters
Mathias Forsberg, Elena Alexandra Serban, Ching-Lien Hsiao, Muhammad Junaid, Jens Birch, Galia Pozina
Novel hybrid organic-inorganic nanostructures fabricated to utilize non-radiative resonant energy transfer mechanism are considered to be extremely attractive for a variety of light emitters for down converting of ultaviolet light and for photovoltaic applications since they can be much more efficient compared to devices grown with common design. Organic-inorganic hybrid structures based on green polyfluorene (F8BT) and GaN (0001) nanorods grown by magnetron sputtering on Si (111) substrates are studied. In such nanorods, stacking faults can form periodic polymorphic quantum wells characterized by bright luminescence...
April 26, 2017: Scientific Reports
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
Evgheni Strelcov, Qingfeng Dong, Tao Li, Jungseok Chae, Yuchuan Shao, Yehao Deng, Alexei Gruverman, Jinsong Huang, Andrea Centrone
Ferroelectricity has been proposed as a plausible mechanism to explain the high photovoltaic conversion efficiency in organic-inorganic perovskites; however, convincing experimental evidence in support of this hypothesis is still missing. Identifying and distinguishing ferroelectricity from other properties, such as piezoelectricity, ferroelasticity, etc., is typically nontrivial because these phenomena can coexist in many materials. In this work, a combination of microscopic and nanoscale techniques provides solid evidence for the existence of ferroelastic domains in both CH3NH3PbI3 polycrystalline films and single crystals in the pristine state and under applied stress...
April 2017: Science Advances
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
Claudia Ojeda-Aristizabal, Elton J G Santos, Seita Onishi, Aiming Yan, Haider Imad Rasool, Salman Kahn, Yinchuan Lv, Drew Latzke, Jairo Velasco, Michael F Crommie, Matthew Sorensen, Kenneth Gotlieb, Chiu-Yun Lin, Kenji Watanabe, Takashi Taniguchi, Alessandra Lanzara, Alex Zettl
Charge transfer at the interface between dissimilar materials is at the heart of electronics and photovoltaics. Here we study the molecular orientation, electronic structure, and local charge transfer at the interface region of C60 deposited on graphene, with and without supporting substrates such as hexagonal boron nitride. We employ ab initio density functional theory with van der Waals (vdW) interactions, and experimentally characterize interface devices using high-resolution transmission electron microscopy and electronic transport...
April 24, 2017: ACS Nano
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
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
Wansun Kim, Inhwa Lee, Dong Yoon Kim, Youn-Yeol Yu, Hae-Yoon Jung, Seyeoul Kwon, Weon Seo Park, Taek-Soo Kim
To protect brittle layers in organic photovoltaic devices, the mechanical neutral plane strategy can be adopted through placing the brittle functional materials close to the neutral plane where stress and strain are zero during bending. However, previous research has been significantly limited in the location and number of materials to protect through using a single neutral plane. In this study, multiple neutral planes are generated using low elastic modulus adhesives and are controlled through quantitative analyses in order to protect the multiple brittle materials at various locations...
May 12, 2017: Nanotechnology
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
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
William White, Christopher D Sanborn, Ronald S Reiter, David M Fabian, Shane Ardo
Replacing passive ion-exchange membranes, like Nafion, with membranes that use light to drive ion transport would allow membranes in photoelectrochemical technologies to serve in an active role. Toward this, we modified per-fluorosulfonic acid ionomer membranes with organic pyrenol-based photoacid dyes to sensitize the membranes to visi-ble light and initiate proton transport. Covalent modification of the membranes was achieved by reacting Nafion sul-fonyl fluoride poly(perfluorosulfonyl fluoride) membranes with 8-hydroxypyrene-1,3,6-tris(2-aminoethylsulfonamide) photoacids...
April 17, 2017: Journal of the American Chemical Society
Oleg V Kozlov, Xiaomeng Liu, Yuriy N Luponosov, Alexander N Solodukhin, Victoria Y Toropynina, Jie Min, Mikhail I Buzin, Svetlana M Peregudova, Christoph J Brabec, Sergei A Ponomarenko, Maxim S Pshenichnikov
Small push-pull molecules attract much attention as prospective donor materials for organic solar cells (OSCs). By chemical engineering, it is possible to combine a number of attractive properties such as broad absorption, efficient charge separation, and vacuum and solution processabilities in a single molecule. Here we report the synthesis and early time photophysics of such a molecule, TPA-2T-DCV-Me, based on the triphenylamine (TPA) donor core and dicyanovinyl (DCV) acceptor end group connected by a thiophene bridge...
March 30, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
Omer Yaffe, Yinsheng Guo, Liang Z Tan, David A Egger, Trevor Hull, Constantinos C Stoumpos, Fan Zheng, Tony F Heinz, Leeor Kronik, Mercouri G Kanatzidis, Jonathan S Owen, Andrew M Rappe, Marcos A Pimenta, Louis E Brus
Hybrid lead-halide perovskites have emerged as an excellent class of photovoltaic materials. Recent reports suggest that the organic molecular cation is responsible for local polar fluctuations that inhibit carrier recombination. We combine low-frequency Raman scattering with first-principles molecular dynamics (MD) to study the fundamental nature of these local polar fluctuations. Our observations of a strong central peak in the cubic phase of both hybrid (CH_{3}NH_{3}PbBr_{3}) and all-inorganic (CsPbBr_{3}) lead-halide perovskites show that anharmonic, local polar fluctuations are intrinsic to the general lead-halide perovskite structure, and not unique to the dipolar organic cation...
March 31, 2017: Physical Review Letters
Jorge Escorihuela, Han Zuilhof
Surface functionalization of inorganic semiconductor substrates, particularly silicon, has focused attention toward many technologically important applications, involving photovoltaic energy, biosensing and catalysis. For such modification processes, oxide-free (H-terminated) silicon surfaces are highly required, and different chemical approaches have been described in the past decades. However, their reactivity is often poor, requiring long reaction times (2-18 h) or the use of UV light (10-30 min). Here, we report a simple and rapid surface functionalization for H-terminated Si(111) surfaces using alkyl silanols...
April 14, 2017: Journal of the American Chemical Society
Sung-Min Lee, Purnim Dhar, Huandong Chen, Angelo Montenegro, Lauren Liaw, Dongseok Kang, Boju Gai, Alexander V Benderskii, Jongseung Yoon
Ultrathin silicon solar cells fabricated by anisotropic wet chemical etching of single-crystalline wafer materials represent an attractive materials platform that could provide many advantages for realizing high-performance, low-cost photovoltaics. However, their intrinsically limited photovoltaic performance arising from insufficient absorption of low-energy photons demands careful design of light management to maximize the efficiency and preserve the cost-effectiveness of solar cells. Herein we present an integrated flexible solar module of ultrathin, nanostructured silicon solar cells capable of simultaneously exploiting spectral upconversion and downshifting in conjunction with multispectral luminescent waveguides and a nanostructured plasmonic reflector to compensate for their weak optical absorption and enhance their performance...
April 25, 2017: ACS Nano
Yen-Ju Hsieh, Yu-Ching Huang, Wei-Shin Liu, Yu-An Su, Cheng-Si Tsao, Syang-Peng Rwei, Leeyih Wang
The impact of the morphological stability of the donor/acceptor mixture under thermal stress on the photovoltaic properties of bulk heterojunction (BHJ) solar cells based on the poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']-dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]-thiophene)-2-carboxylate-2,6-diyl]/phenyl-C61-butyric acid methyl ester (PTB7-Th/PC61BM) blend is extensively investigated. Both optical microscopy and transmission electron microscopy micrographs show that long-term high-temperature aging stimulates the formation of microscale clusters, the size of which, however, is about 1 order of magnitude smaller than those observed in thermally annealed poly(3-hexylthiophene)/PC61BM composite film...
April 18, 2017: ACS Applied Materials & Interfaces
Wenbo Peng, Xingfu Wang, Ruomeng Yu, Yejing Dai, Haiyang Zou, Aurelia C Wang, Yongning He, Zhong Lin Wang
Self-powered photodetectors (PDs) have long been realized by utilizing photovoltaic effect and their performances can be effectively enhanced by introducing the piezo-phototronic effect. Recently, a novel pyro-phototronic effect is invented as an alternative approach for performance enhancement of self-powered PDs. Here, a self-powered organic/inorganic PD is demonstrated and the influences of externally applied strain on the pyro-phototronic and the photovoltaic effects are thoroughly investigated. Under 325 nm 2...
April 11, 2017: Advanced Materials
Ievgen Levchuk, Andres Osvet, Xiaofeng Tang, Marco Brandl, Jose Dario Perea, Florian Hoegl, Gebhard Josef Matt, Rainer Hock, Miroslaw Batentschuk, Christoph J Brabec
In the past few years, hybrid organic-inorganic and all-inorganic metal halide perovskite nanocrystals have become one of the most interesting materials for optoelectronic applications. Here, we report a facile and rapid room temperature synthesis of 15-25 nm formamidinium CH(NH2)2PbX3 (X=Cl, Br, I, or mixed Cl/Br and Br/I) colloidal nanocrystals by ligand-assisted re-precipitation (LARP). The cubic and platelet-like nanocrystals with their emission in the range of 415-740 nm, full width at half maximum (FWHM) of 20-44 nm and radiative lifetimes of 5-166 ns, enable band gap tuning by halide composition as well as by their thickness tailoring; they have a high photoluminescence quantum yield (up to 85%), colloidal and thermodynamic stability...
April 7, 2017: Nano Letters
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