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organic photovoltaic

J H Du, H Jin, Z K Zhang, D D Zhang, S Jia, L P Ma, W C Ren, H M Cheng, P L Burn
The large surface roughness, low work function and high cost of transparent electrodes using multilayer graphene films can limit their application in organic photovoltaic (OPV) cells. Here, we develop single layer graphene (SLG) films as transparent anodes for OPV cells that contain light-absorbing layers comprised of the evaporable molecular organic semiconductor materials, zinc phthalocyanine (ZnPc)/fullerene (C60), as well as a molybdenum oxide (MoOx) interfacial layer. In addition to an increase in the optical transmittance, the SLG anodes had a significant decrease in surface roughness compared to two and four layer graphene (TLG and FLG) anodes fabricated by multiple transfer and stacking of SLGs...
December 1, 2016: Nanoscale
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
Ramesh Ghosh, P K Giri
Semiconductor nanowires (NWs), in particular Si NWs, have attracted much attention in the last decade for their unique electronic properties and potential applications in several emerging areas. With the introduction of heterostructures (HSs) on NWs, new functionalities are obtained and the device performance is improved significantly in many cases. Due to the easy fabrication techniques, excellent optoelectronic properties and compatibility of forming HSs with different inorganic/organic materials, Si NW HSs have been utilized in various configurations and device architectures...
November 28, 2016: Nanotechnology
Kyohei Nakano, Keisuke Tajima
Recent progress regarding planar heterojunctions (PHJs) is reviewed, with respect to the fundamental understanding of the photophysical processes at the donor/acceptor interfaces in organic photovoltaic devices (OPVs). The current state of OPV research is summarized and the advantages of PHJs as models for exploring the relationship between organic interfaces and device characteristics described. The preparation methods and the characterization of PHJ structures to provide key points for the appropriate handling of PHJs...
November 25, 2016: Advanced Materials
Fan Zhang, Jun Song, Ming Chen, Junchen Liu, Yuying Hao, Yuncai Wang, Junle Qu, Pengju Zeng
: Organic-inorganic metal halide perovskites have led to remarkable advancements in emerging photovoltaics. The rapid increase in the power conversion efficiency (PCE) of PSCs has been mainly achieved by improving perovskite morphology and crystallinity. Herein, we report a simple and effective means to improve perovskite grain sizes using a porous hole transport layer (i.e. , PEDOT: PSS in this work). We used polystyrene nanospheres as a sacrificial template to fabricate the porous-PEDOT:PSS...
November 24, 2016: Physical Chemistry Chemical Physics: PCCP
Kyu-Sup Lee, Rira Kang, Byungwoo Son, Dong-Yu Kim, Nan Ei Yu, Do-Kyeong Ko
Hybrid structures of silicon with organic-inorganic perovskites are proposed for optically controllable switching of terahertz (THz) waves over a broad spectral range from 0.2 to 2THz. A 532-nm external laser was utilized to generate photoexcited free carriers at the devices and consequentially to control the terahertz amplitude modulation, obtaining a depth of up to 68% at a laser irradiance of 1.5 W/cm(2). In addition, we compared the performances from three types of perovskite devices fabricated via different solution processing methods and suggested a stable and highly efficient THz switch based on a one-step processing...
November 24, 2016: Scientific Reports
Peng-Fei Li, Yuan-Yuan Tang, Zhong-Xia Wang, Heng-Yun Ye, Yu-Meng You, Ren-Gen Xiong
Molecular ferroelectrics are currently an active research topic in the field of ferroelectric materials. As complements or alternatives of conventional inorganic ferroelectrics, they have been designed to realize various novel properties, ranging from multiferroicity and semiconductive ferroelectricity to ferroelectric photovoltaics and ferroelectric luminescence. The stabilizing of ferroelectricity in various systems is owing to the flexible tailorability of the organic components. Here we describe the construction of optically active molecular ferroelectrics by introducing homochiral molecules as polar groups...
November 23, 2016: Nature Communications
Nevena Marinova, Silvia Valero, Juan Luis Delgado
In the last decades organic solar cells (OSCs) have been considered as a promising photovoltaic technology with the potential to provide reasonable power conversion efficiencies combined with low cost and easy processability. Unexpectedly, Perovskite Solar Cells (PSCs) have experienced unprecedented rise in Power Conversion Efficiency (PCE) thus emerging as a highly efficient photovoltaic technology. OSCs and PSCs are two different kind of devices with distinct charge generation mechanism, which however share some similarities in the materials processing, thus standard strategies developed for OSCs are currently being employed in PSCs...
November 11, 2016: Journal of Colloid and Interface Science
Abraham Yosipof, Omer Kaspi, Koushik Majhi, Hanoch Senderowitz
Material informatics may provide meaningful insights and powerful predictions for the development of new and efficient Metal Oxide (MO) based solar cells. The main objective of this paper is to establish the usefulness of data reduction and visualization methods for analyzing data sets emerging from multiple all-MOs solar cell libraries. For this purpose, two libraries, TiO2 |Co3 O4 and TiO2 |Co3 O4 |MoO3 , differing only by the presence of a MoO3 layer in the latter were analyzed with Principal Component Analysis and Self-Organizing Maps...
December 2016: Molecular Informatics
Derya Baran, Raja Shahid Ashraf, David A Hanifi, Maged Abdelsamie, Nicola Gasparini, Jason A Röhr, Sarah Holliday, Andrew Wadsworth, Sarah Lockett, Marios Neophytou, Christopher J M Emmott, Jenny Nelson, Christoph J Brabec, Aram Amassian, Alberto Salleo, Thomas Kirchartz, James R Durrant, Iain McCulloch
Technological deployment of organic photovoltaic modules requires improvements in device light-conversion efficiency and stability while keeping material costs low. Here we demonstrate highly efficient and stable solar cells using a ternary approach, wherein two non-fullerene acceptors are combined with both a scalable and affordable donor polymer, poly(3-hexylthiophene) (P3HT), and a high-efficiency, low-bandgap polymer in a single-layer bulk-heterojunction device. The addition of a strongly absorbing small molecule acceptor into a P3HT-based non-fullerene blend increases the device efficiency up to 7...
November 21, 2016: Nature Materials
Ailing Tang, Chuanlang Zhan, Jiannian Yao, Erjun Zhou
After the first report in 2008, diketopyrrolopyrrole (DPP)-based small-molecule photovoltaic materials have been intensively explored. The power conversion efficiencies (PCEs) for the DPP-based small-molecule donors have been improved up to 8%. Furthermore, through judicious structure modification, DPP-based small molecules can also be converted into electron-acceptor materials, and, recently, some exciting progress has been achieved. The development of DPP-based photovoltaic small molecules is summarized here, and the photovoltaic performance is discussed in relation to structural modifications, such as the variations of donor-acceptor building blocks, alkyl substitutions, and the type of conjugated bridges, as well as end-capped groups...
November 9, 2016: Advanced Materials
Li-Ming Yang, Guo-Yong Fang, Jing Ma, Raghani Pushpa, Eric Ganz
Inspired by recent experimental fabrication of mono-halogenated versions of Metal-Organic Framework MOF-5 (i.e., X-MOF-5, X = F to I) and some experimentally known fully halogenated MOF compounds, we systematically studied frameworks incorporating full halogenation of the BDC linkers of the prototypical Iso-Reticular Metal-Organic Framework (IRMOF) series, exemplified by MOF-5. Using quantum chemistry calculations, we find that halogenation leads to a 90° rotation of the aryl group, which is mainly ascribed to overcrowding between halogen atoms and the carboxyl and benzene ring and strong repulsion among in-plane atoms/groups...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
Manohar Reddy Busireddy, Venkata Niladri Raju Mantena, Narendra Reddy Chereddy, Balaiah Shanigaram, Bhanuprakash Kotamarthi, Subhayan Biswas, Ganesh Datt Sharma, Jayathirtha Rao Vaidya
A novel, NIR absorbing organic small molecular donor material denoted as ICT3 with an A-D-D-D-A architecture having dithieno[3,2-b:2',3'-d]pyrrole (DTP) and butylrhodanine as donor and acceptor moieties, respectively, is synthesized and its thermal, photophysical, electrochemical and photovoltaic properties are explored. ICT3 has excellent stability over a broad range of temperatures with a decomposition temperature (Td corresponds to 5% weight loss) of 372 °C, soluble in most common organic solvents (solubility up to 30 mg mL(-1)) and suitable for solution processing during device fabrication...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
Abhishek Swarnkar, Ashley R Marshall, Erin M Sanehira, Boris D Chernomordik, David T Moore, Jeffrey A Christians, Tamoghna Chakrabarti, Joseph M Luther
We show nanoscale phase stabilization of CsPbI3 quantum dots (QDs) to low temperatures that can be used as the active component of efficient optoelectronic devices. CsPbI3 is an all-inorganic analog to the hybrid organic cation halide perovskites, but the cubic phase of bulk CsPbI3 (α-CsPbI3)-the variant with desirable band gap-is only stable at high temperatures. We describe the formation of α-CsPbI3 QD films that are phase-stable for months in ambient air. The films exhibit long-range electronic transport and were used to fabricate colloidal perovskite QD photovoltaic cells with an open-circuit voltage of 1...
October 7, 2016: Science
Mohamed Bourass, Adil Touimi Benjelloun, Mohammed Benzakour, Mohammed Mcharfi, Mohammed Hamidi, Si Mohamed Bouzzine, Mohammed Bouachrine
BACKGROUND: Novel six organic donor-π-acceptor molecules (D-π-A) used for Bulk Heterojunction organic solar cells (BHJ), based on thienopyrazine were studied by density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches, to shed light on how the π-conjugation order influence the performance of the solar cells. The electron acceptor group was 2-cyanoacrylic for all compounds, whereas the electron donor unit was varied and the influence was investigated. METHODS: The TD-DFT method, combined with a hybrid exchange-correlation functional using the Coulomb-attenuating method (CAM-B3LYP) in conjunction with a polarizable continuum model of salvation (PCM) together with a 6-31G(d,p) basis set, was used to predict the excitation energies, the absorption and the emission spectra of all molecules...
2016: Chemistry Central Journal
Namyoung Ahn, Kwisung Kwak, Min Seok Jang, Heetae Yoon, Byung Yang Lee, Jong-Kwon Lee, Peter V Pikhitsa, Junseop Byun, Mansoo Choi
Perovskite solar cells have shown unprecedent performance increase up to 22% efficiency. However, their photovoltaic performance has shown fast deterioration under light illumination in the presence of humid air even with encapulation. The stability of perovskite materials has been unsolved and its mechanism has been elusive. Here we uncover a mechanism for irreversible degradation of perovskite materials in which trapped charges, regardless of the polarity, play a decisive role. An experimental setup using different polarity ions revealed that the moisture-induced irreversible dissociation of perovskite materials is triggered by charges trapped along grain boundaries...
November 10, 2016: Nature Communications
Pierre Boufflet, Sebastian Wood, Jessica Wade, Zhuping Fei, Ji-Seon Kim, Martin Heeney
The microstructure of the active blend layer has been shown to be a critically important factor in the performance of organic solar devices. Block copolymers provide a potentially interesting avenue for controlling this active layer microstructure in solar cell blends. Here we explore the impact of backbone fluorination in block copolymers of poly(3-octyl-4-fluorothiophene)s and poly(3-octylthiophene) (F-P3OT-b-P3OT). Two block co-polymers with varying block lengths were prepared via sequential monomer addition under Kumada catalyst transfer polymerisation (KCTP) conditions...
2016: Beilstein Journal of Organic Chemistry
Forrest S Etheridge, Roshan J Fernando, Sandra Pejić, Matthias Zeller, Geneviève Sauvé
Homoleptic zinc(II) complexes of di(phenylacetylene)azadipyrromethene (e.g., Zn(WS3)2) are potential non-fullerene electron acceptors for organic photovoltaics. To tune their properties, fluorination of Zn(WS3)2 at various positions was investigated. Three fluorinated azadipyrromethene-based ligands were synthesized with fluorine at the para-position of the proximal and distal phenyl groups, and at the pyrrolic phenylacetylene moieties. Additionally, a CF3 moiety was added to the pyrrolic phenyl positions to study the effects of a stronger electron withdrawing unit at that position...
2016: Beilstein Journal of Organic Chemistry
Ni Yin, Lilei Wang, Yi Lin, Jinduo Yi, Lingpeng Yan, Junyan Dou, Hai-Bo Yang, Xin Zhao, Chang-Qi Ma
Benzo[1,2-b:4,5-b']dithiophene (BDT) is an excellent building block for constructing π-conjugated molecules for the use in organic solar cells. In this paper, four 4,8-bis(5-alkyl-2-thienyl)benzo[1,2-b:4,5-b']dithiophene (TBDT)-containing A-π-D-π-A-type small molecules (COOP-nHT-TBDT, n = 1, 2, 3, 4), having 2-cyano-3-octyloxy-3-oxo-1-propenyl (COOP) as terminal group and regioregular oligo(3-hexylthiophene) (nHT) as the π-conjugated bridge unit were synthesized. The optical and electrochemical properties of these compounds were systematically investigated...
2016: Beilstein Journal of Organic Chemistry
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