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Solar cells

María Castro-Alférez, María Inmaculada Polo-López, Pilar Fernández-Ibáñez
Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E...
December 2, 2016: Scientific Reports
Sang-Won Lee, Seongtak Kim, Soohyun Bae, Kyungjin Cho, Taewon Chung, Laura E Mundt, Seunghun Lee, Sungeun Park, Hyomin Park, Martin C Schubert, Stefan W Glunz, Yohan Ko, Yongseok Jun, Yoonmook Kang, Hae-Seok Lee, Donghwan Kim
Although the power conversion efficiency of perovskite solar cells has increased from 3.81% to 22.1% in just 7 years, they still suffer from stability issues, as they degrade upon exposure to moisture, UV light, heat, and bias voltage. We herein examined the degradation of perovskite solar cells in the presence of UV light alone. The cells were exposed to 365 nm UV light for over 1,000 h under inert gas at <0.5 ppm humidity without encapsulation. 1-sun illumination after UV degradation resulted in recovery of the fill factor and power conversion efficiency...
December 2, 2016: Scientific Reports
Matthew J Turnbull, Daniel Vaccarello, Yun Mui Yiu, Tsun-Kong Sham, Zhifeng Ding
Solar cell performance is most affected by the quality of the light absorber layer. For thin-film devices, this becomes a two-fold problem of maintaining a low-cost design with well-ordered nanocrystal (NC) structure. The use of Cu2ZnSnS4 (CZTS) NCs as the light absorber films forms an ideal low-cost design, but the quaternary structure makes it difficult to maintain a well-ordered layer without the use of high-temperature treatments. There is little understanding of how CZTS NC structures affect the photoconversion efficiency, the charge-carriers, and therefore the performance of the device manufactured from it...
November 28, 2016: Journal of Chemical Physics
Luca La Notte, Enrica Villari, Alessandro Lorenzo Palma, Alberto Sacchetti, Maria Michela Giangregorio, Giovanni Bruno, Aldo Di Carlo, Giuseppe Valerio Bianco, Andrea Reale
A five-layer (5L) graphene on a glass substrate has been demonstrated as a transparent conductive electrode to replace indium tin oxide (ITO) in organic photovoltaic devices. The required low sheet resistance, while maintaining high transparency, and the need of a wettable surface are the main issues. To overcome these, two strategies have been applied: (i) the p-doping of the multilayer graphene, thus reaching 25 Ω □(-1) or (ii) the O2-plasma oxidation of the last layer of the 5L graphene that results in a contact angle of 58° and a sheet resistance of 134 Ω □(-1)...
December 1, 2016: Nanoscale
Haijun Bin, Liang Gao, Zhi-Guo Zhang, Yankang Yang, Yindong Zhang, Chunfeng Zhang, Shanshan Chen, Lingwei Xue, Changduk Yang, Min Xiao, Yongfang Li
Simutaneously high open circuit voltage and high short circuit current density is a big challenge for achieving high efficiency polymer solar cells due to the excitonic nature of organic semdonductors. Herein, we developed a trialkylsilyl substituted 2D-conjugated polymer with the highest occupied molecular orbital level down-shifted by Si-C bond interaction. The polymer solar cells obtained by pairing this polymer with a non-fullerene acceptor demonstrated a high power conversion efficiency of 11.41% with both high open circuit voltage of 0...
December 1, 2016: Nature Communications
Eva-Maria Willing, Thomas Piofczyk, Andreas Albert, J Barbro Winkler, Korbinian Schneeberger, Ales Pecinka
Ground levels of solar UV-B radiation induce DNA damage. Sessile phototrophic organisms such as vascular plants are recurrently exposed to sunlight and require UV-B photoreception, flavonols shielding, direct reversal of pyrimidine dimers and nucleotide excision repair for resistance against UV-B radiation. However, the frequency of UV-B-induced mutations is unknown in plants. Here we quantify the amount and types of mutations in the offspring of Arabidopsis thaliana wild-type and UV-B-hypersensitive mutants exposed to simulated natural UV-B over their entire life cycle...
December 1, 2016: Nature Communications
Zhiping Wang, David P McMeekin, Nobuya Sakai, Stephan van Reenen, Konrad Wojciechowski, Jay B Patel, Michael B Johnston, Henry J Snaith
Air-stable doping of the n-type fullerene layer in an n-i-p planar heterojunction perovskite device is capable of enhancing device efficiency and improving device stability. Employing a (HC(NH2 )2 )0.83 Cs0.17 Pb(I0.6 Br0.4 )3 perovskite as the photoactive layer, glass-glass laminated devices are reported, which sustain 80% of their "post burn-in" efficiency over 3400 h under full sun illumination in ambient conditions.
December 1, 2016: Advanced Materials
Xiaojuan Shen, Ling Chen, Jianmei Pan, Yue Hu, Songjun Li, Jie Zhao
Hybrid silicon/organic solar cells have been recently extensively investigated due to their simple structure and low-cost fabrication process. However, the efficiency of the solar cells is greatly limited by the barrier height as well as the carrier recombination at the silicon/organic interface. In this work, hydrochloroplatinic acid (H2PtCl6) is employed into the poly(3,4-ethlenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solution, and the work function (WF) of the PEDOT:PSS layer has been successfully improved...
December 2016: Nanoscale Research Letters
Sang-Hun Lee, Barna Dudok, Vipan K Parihar, Kwang-Mook Jung, Miklós Zöldi, Young-Jin Kang, Mattia Maroso, Allyson L Alexander, Gregory A Nelson, Daniele Piomelli, István Katona, Charles L Limoli, Ivan Soltesz
In the not too distant future, humankind will embark on one of its greatest adventures, the travel to distant planets. However, deep space travel is associated with an inevitable exposure to radiation fields. Space-relevant doses of protons elicit persistent disruptions in cognition and neuronal structure. However, whether space-relevant irradiation alters neurotransmission is unknown. Within the hippocampus, a brain region crucial for cognition, perisomatic inhibitory control of pyramidal cells (PCs) is supplied by two distinct cell types, the cannabinoid type 1 receptor (CB1)-expressing basket cells (CB1BCs) and parvalbumin (PV)-expressing interneurons (PVINs)...
November 30, 2016: Brain Structure & Function
Hanan Osman-Ponchet, Karine Sevin, Alexandre Gaborit, Magali Kouidhi, Johanna Hanaizi, Pierre Comby, Bernard Ruty, Guy Bouvier
BACKGROUND: Photodynamic therapy (PDT) is a successful treatment for non-melanoma skin cancers. Methyl-aminolevulinate (MAL) is metabolized to protoporphyrin IX (PpIX) which accumulates in the skin lesion and which generates a painful photochemical toxic reaction upon red light exposure. PDT using daylight (DL) exposure is now used to reduce pain and subjects are advised to protect the areas with sunscreen. This work investigated the effect of sunscreen on MAL penetration and PpIX photoactivation in ex vivo human skin...
November 26, 2016: Photodiagnosis and Photodynamic Therapy
Olof Bäcke, Camilla Lindqvist, Amaia Diaz de Zerio Mendaza, Stefan Gustafsson, Ergang Wang, Mats R Andersson, Christian Müller, Per Magnus Kristiansen, Eva Olsson
We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope...
November 21, 2016: Ultramicroscopy
Paulo Vale
Laboratory cultures of the paralytic shellfish poisoning producing microalga Gymnodinium catenatum were subjected to a hypo-osmotic shock and changes in cell concentration were observed in two separate experiments of 8 and 24 hours duration, respectively. The increase in geomagnetic activity (GMA), radio and X-ray fluxes and solar X-ray flares were negatively correlated with cell numbers. Cell losses were observed in the short experiment, but not in the longest one. GMA action was related to the course of the experimental period, while electromagnetic radiation (EMR) was only significantly related when the previous hours before the experiments were considered...
November 30, 2016: General Physiology and Biophysics
Chunyu Liu, Zhiqi Li, Zhihui Zhang, Xinyuan Zhang, Liang Shen, Wenbin Guo, Liu Zhang, Yongbing Long, Shengping Ruan
Tetrafluoro-tetracyanoquinodimethane (F4-TCNQ), a strong molecular acceptor, has been proved to be an excellent candidate to achieve the p-type doping effect. When F4-TCNQ is incorporated into a poly(3-hexylthiophene) (P3HT): indene-C60 bisadduct (ICBA) active layer, superior behavior upon inducing polymer donor excited electron transport is demonstrated due to the addition of a deep-lying lowest unoccupied molecular orbital (LUMO) from F4-TCNQ, leading to the realization of organic solar cells (OSCs) with an improved power conversion efficiency (PCE) of 5...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
Jin Chang, Yuhei Ogomi, Chao Ding, Yao Hong Zhang, Taro Toyoda, Shuzi Hayase, Kenji Katayama, Qing Shen
The surface chemistry of colloidal quantum dots (QDs) plays an important role in determining the photoelectric properties of QD films and the corresponding quantum dot heterojunction solar cells (QDHSCs). To investigate the effects of the ligand structure on the photovoltaic performance and exciton dynamics of QDHSCs, PbS QDHSCs were fabricated by the solid state ligand exchange method with mercaptoalkanoic acid as the cross-linking ligand. Temperature-dependent photoluminescence and ultrafast transient absorption spectra show that the electronic coupling and charge transfer rate within QD ensembles were monotonically enhanced as the ligand length decreased...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
Guo-Jun Kang, Chao Song, Xue-Feng Ren
The electronic geometries and optical properties of two D-π-A type zinc porphyrin dyes (NCH₃-YD2 and TPhe-YD) were systematically investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to reveal the origin of significantly altered charge transfer enhancement by changing the electron donor of the famous porphyrin-based sensitizer YD2-o-C8. The molecular geometries and photophysical properties of dyes before and after binding to the TiO₂ cluster were fully investigated...
November 25, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Chi-Ho Siu, Lawrence Tien Lin Lee, Po-Yu Ho, Cheuk-Lam Ho, Tao Chen, Songwut Suramitr, Supa Hannongbua, Zhiyuan Xie, Mingdeng Wei, Wai-Yeung Wong
A new series of acetylene-bridged phenothiazine-based dianchoring dyes have been synthesized and fully characterized, and used as the photoactive layer for the fabrication of conventional dye-sensitized solar cells (DSSCs). Tuning of their photophysical and electrochemical properties using different π-conjugated aromatic rings as the central bridge has been demonstrated. This molecular design strategy successfully inhibits the undesirable charge recombination and prolongs the electron lifetime significantly to improve the power conversion efficiency (η), which were proven by the detailed studies of electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD)...
November 29, 2016: Chemistry, An Asian Journal
Masoud Ghasemi, Long Ye, Qianqian Zhang, Liang Yan, Joo-Hyun Kim, Omar Awartani, Wei You, Abay Gadisa, Harald Ade
A sequential-casting ternary method is developed to create stratified bulk heterojunction (BHJ) solar cells, in which the two BHJ layers are spin cast sequentially without the need of adopting a middle electrode and orthogonal solvents. This method is found to be particularly useful for polymers that form a mechanically alloyed morphology due to the high degree of miscibility in the blend.
November 29, 2016: Advanced Materials
Weifu Sun, Zihan Chen, Junli Zhou, Dongyu Li, Zhen Huang, Xiao Jin, Qin Zhang, Feng Li, Qinghua Li
In this work, ytterbium-erbium co-doped strontium molybdate (SrMoO4, SMO) nanophosphors (NPs), denoted as SMO:Yb/Er, have been successfully prepared. These NPs were then incorporated into TiO2 acceptor films in hybrid solar cells to enhance light harvesting by virtue of an up-conversion process where low energy photons can be converted into high energy photons through multi-photon processes. The results showed that the SMO:Yb/Er single crystal NPs are capable of turning near infrared photons into visible ones that can be easily captured by poly(thieno[3,4-b]-thiophene/benzodithiophene) (PTB7)...
November 29, 2016: Physical Chemistry Chemical Physics: PCCP
Jagriti Gupta, Jeotikanta Mohapatra, D Bahadur
We present here the multitasking capabilities of Ag-embedded ZnO nanocomposites (Ag-ZnO NCs), which include the photocatalytic degradation of organic dyes, bacterial inhibition, and cancer therapeutics. Ag-embedded ZnO nanocomposites (Ag-ZnO NCs) of mesoporous spherical morphology (size ∼ 150 ± 50 nm) are successfully synthesized by a facile and single step soft-chemical approach. To understand the effect of Ag loading on multitasking properties, Ag-ZnO NCs are synthesized with different wt% of Ag. It was found that Ag5-ZnO NCs (5 wt% of Ag) showed excellent solar light-induced photocatalytic degradation properties against both cationic as well as anionic dyes...
November 29, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Romeo Saldívar-Lucio, Emanuele Di Lorenzo, Miguel Nakamura, Héctor Villalobos, Daniel Lluch-Cota, Pablo Del Monte-Luna
The seasonal and interannual variability of vertical transport (upwelling/downwelling) has been relatively well studied, mainly for the California Current System, including low-frequency changes and latitudinal heterogeneity. The aim of this work was to identify potentially predictable patterns in upwelling/downwelling activity along the North American west coast and discuss their plausible mechanisms. To this purpose we applied the min/max Autocorrelation Factor technique and time series analysis. We found that spatial co-variation of seawater vertical movements present three dominant low-frequency signals in the range of 33, 19 and 11 years, resembling periodicities of: atmospheric circulation, nodal moon tides and solar activity...
2016: PloS One
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