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Solar photovoltaic

Xinwei Chen, Si-Lu Tao, Cong Fan, Dongcheng Chen, Ling Zhou, Hui Lin, Cai-Jun Zheng, Shi-Jian Su
Ternary bulk heterojunction (BHJ) is a brilliant photovoltaic technology for improving the performance of organic solar cells (OSCs), since the light absorption range can be significantly extended by using multiple donors or acceptor materials. In this paper, coumarin7 (C7), a small organic molecule typical led used in organic light-emitting diodes, was initially exploited as second electron-donor component in ternary bulk heterojunction OSCs along with conventional blend system spolythieno[3,4-b]-thiophene/benzodithiophene(PTB7) and [6,6]-phenyl-C71 -butyric acid methyl(PC71 BM)...
August 15, 2017: ACS Applied Materials & Interfaces
Carlito S Ponseca, Pavel Chábera, Jens Uhlig, Petter Persson, Villy Sundström
Electrons are the workhorses of solar energy conversion. Conversion of the energy of light to electricity in photovoltaics, or to energy-rich molecules (solar fuel) through photocatalytic processes, invariably starts with photoinduced generation of energy-rich electrons. The harvesting of these electrons in practical devices rests on a series of electron transfer processes whose dynamics and efficiencies determine the function of materials and devices. To capture the energy of a photogenerated electron-hole pair in a solar cell material, charges of opposite sign have to be separated against electrostatic attractions, prevented from recombining and being transported through the active material to electrodes where they can be extracted...
August 14, 2017: Chemical Reviews
Zhi-Wen Zhao, Qing-Qing Pan, Shuang-Bao Li, Yu-Ai Duan, Yun Geng, Min Zhang, Zhong-Min Su
A series of polymer donor materials 1-5 based on diketopyrrolopyrrole and thiophene unit which have been widely used in organic solar cells (OSCs) were investigated based on quantum chemical calculations. The effect of fluorine and cyano substitutions in polymer donor materials was focused on. Based on the investigation on electronic structures and optical properties of the reported molecules 1 and 2 and the analysis on some parameters relevant to charge dissociation ability at donor/acceptor interface constituted by 1 and 2 with PC61BM such as intermolecular charge transfer and recombination, driving force and Coulombic bound energy, we explained why fluorine substitution can improve OPV efficiency through strengthening eletron-withdrawing ability from a theoretical perspective...
August 2, 2017: Journal of Molecular Graphics & Modelling
Mannix Padayhag Balanay, Dong Hee Kim
Bacteriochlorin-based dyes, having a push-pull type of configuration similar to the YD2 dye, were theoretically designed based on the modification of the macrocycle and π-conjugated bridge for use in dye-sensitized solar cells. Various parameters were assessed to determine its structure-property relationships, such as the absorption profile based on time-dependent density functional theory, non-linear optical properties from (hyper)polarizability data, ground- and excited-state oxidation potentials, and the electronic properties of the free and adsorbed dyes...
August 11, 2017: Journal of Physical Chemistry. A
Hong Wang, Yi Hu, Shivaraj Yellappa, Michael B Thomas, R G Waruna Jinadasa, Alex Matus, Max Shulman, Francis D'souza
A novel class of β-functionalized push-pull zinc opp-dibenzoporphyrins were designed, synthesized and utilized as sensitizers for dye-sensitized solar cells. Spectral, electrochemical and computational studies were systematically performed to evaluate their spectral coverage, redox behavior and electronic structures. These porphyrins displayed much broader spectral coverage and more facile oxidation upon extension of π-conjugation. Free-energy calculations and femtosecond transient absorption studies (charge injection rate in the range of 1011 s-1) suggest efficient charge injection from the excited singlet state of porphyrin to the conduction band of the TiO2...
August 11, 2017: Chemistry, An Asian Journal
Silvio J Prado, Gilmar Eugenio Marques, Augusto Alcalde
In this work we show calculation of optimized efficiencies of intermediate band solar cells (IBSC) based on Mn-doped II-VI CdTe/CdMnTe coupled quantum dot (QD) structures. We focus our attention on the combined effects of geometrical and Mn-doping parameters on the optical properties and solar cell efficiency. In the framework of k . p theory, we accomplished detailed calculations of electronic structure, transition energies, optical selection rules and their corresponding intra- and interband oscillator strengths...
August 11, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Xavier A Jeanbourquin, Aiman Rahmanudin, Xiaoyun Yu, Melissa Johnson, Néstor Guijarro, Liang Yao, Kevin Sivula
Ternary bulk heterojunctions with cascade-type energy-level configurations are of significant interest for further improving the power conversion efficiency (PCE) of organic solar cells. However, controlling the self-assembly in solution-processed ternary blends remains a key challenge. Herein, we leverage the ability to control the crystallinity of molecular semiconductors via a spiro linker to demonstrate a simple strategy suggested to drive the self-assembly of an ideal charge-cascade morphology. Spirobifluorene (SF) derivatives with optimized energy levels from diketopyrrolopyrrole (DPP) or perylenediimide (PDI) components, coded as SF-(DPP)4 and SF-(PDI)4, are synthesized and investigated for application as ternary components in the host blend of poly(3-hexylthiophene-2,5-diyl):[6,6]phenyl-C61-butyric acid methyl ester (P3HT:PCBM)...
August 10, 2017: ACS Applied Materials & Interfaces
Hua Sun, Xin Song, Jian Xie, Po Sun, Peiyang Gu, Chang Mei Liu, Fei Chen, Qi Chun Zhang, Zhi-Kuan Chen, Wei Huang
A perylenediimide (PDI)-based small molecular (SM) acceptor with both an extended π-conjugation and a three dimensional structure concurrently is critical for achieving high performance PDI-based fullerene-free organic solar cells (OSCs). In this work, we designed and synthesized a novel PDI-based SM acceptor possessing both characteristics by fusing PDI units with a spiro core of 4,4'-spirobi[cyclopenta[2,1-b;3,4-b']dithiophene(SCPDT) through the -position of the thiophene rings. An enhanced strong absorption in the range of 350-520 nm and arisen LUMO energy level of FSP was observed, compared with previous reported acceptor SCPDT-PDI4, in which the PDI units and SCPDT are not fused...
August 10, 2017: ACS Applied Materials & Interfaces
Fahmi F Muhammad, Mohd Y Yahya, Shilan S Hameed, Fakhra Aziz, Khaulah Sulaiman, Mariwan A Rasheed, Zubair Ahmad
In this research work, numerical simulations are performed to correlate the photovoltaic parameters with various internal and external factors influencing the performance of solar cells. Single-diode modeling approach is utilized for this purpose and theoretical investigations are compared with the reported experimental evidences for organic and inorganic solar cells at various electrical and thermal conditions. Electrical parameters include parasitic resistances (Rs and Rp) and ideality factor (n), while thermal parameters can be defined by the cells temperature (T)...
2017: PloS One
Sang Woo Seo, Ha Seung Lee, Dong Hee Shin, Ju Hwan Kim, Chan Wook Jang, Jong Min Kim, Sung Kim, Suk-Ho Choi
We first employ highly-stable and -flexible (CF<sub>3</sub>SO<sub>2</sub>)<sub>2</sub>NH-doped graphene (TFSA/GR) and GR-encapsulated TFSA/GR (GR/TFSA/GR) transparent conductive electrodes (TCEs) prepared on polyethylene terephthalate substrates for flexible organic solar cells (OSCs). Compared to conventional indium tin oxide (ITO) TCEs, the TFSA-doped-GR TCEs show higher optical transmittance and larger sheet resistance. The TFSA/GR and GR/TFSA/GR TCEs show work functions of 4...
August 9, 2017: Nanotechnology
Kui-Ying Nie, Jing Li, Xuanhu Chen, Yang Xu, Xuecou Tu, Fang-Fang Ren, Qingguo Du, Lan Fu, Lin Kang, Kun Tang, Shulin Gu, Rong Zhang, Peiheng Wu, Youdou Zheng, Hark Hoe Tan, Chennupati Jagadish, Jiandong Ye
Intermediate band solar cells (IBSCs) are conceptual and promising for next generation high efficiency photovoltaic devices, whereas, IB impact on the cell performance is still marginal due to the weak absorption of IB states. Here a rational design of a hybrid structure composed of ZnTe:O/ZnO core-shell nanowires (NWs) with Al bowtie nanoantennas is demonstrated to exhibit strong ability in tuning and enhancing broadband light response. The optimized nanowire dimensions enable absorption enhancement by engineering leaky-mode dielectric resonances...
August 8, 2017: Scientific Reports
Gede W P Adhyaksa, Eric Johlin, Erik C Garnett
Tandem photovoltaics, combining absorber layers with two distinct band gap energies into a single device, provide a practical solution to reduce thermalization losses in solar energy conversion. Traditionally, tandem devices have been assembled using two-terminal (2-T) or four-terminal (4-T) configurations; the 2-T limits the tandem performance due to the series connection requiring current matching, while the standard 4-T configuration requires at least three transparent electrical contacts, which reduce the total collected power due to unavoidable parasitic absorption...
August 16, 2017: Nano Letters
Elisa Collado-Fregoso, Samantha N Hood, Safa Shoaee, Bob C Schroeder, Iain McCulloch, Ivan Kassal, Dieter Neher, James R Durrant
In this Letter, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and nonintercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the nonintercalated system and almost vanishes when energetic disorder is included in the model...
August 16, 2017: Journal of Physical Chemistry Letters
Diego Antolín, Nicolás Medrano, Belén Calvo, Pedro A Martínez
This paper presents a low-cost high-efficiency solar energy harvesting system to power outdoor wireless sensor nodes. It is based on a Voltage Open Circuit (VOC) algorithm that estimates the open-circuit voltage by means of a multilayer perceptron neural network model trained using local experimental characterization data, which are acquired through a novel low cost characterization system incorporated into the deployed node. Both units-characterization and modelling-are controlled by the same low-cost microcontroller, providing a complete solution which can be understood as a virtual pilot cell, with identical characteristics to those of the specific small solar cell installed on the sensor node, that besides allows an easy adaptation to changes in the actual environmental conditions, panel aging, etc...
August 4, 2017: Sensors
Wei-Qi Huang, Shi-Rong Liu, Zhong-Mei Huang, Xue-Ke Wu, Chao-Jian Qin
We have fabricated the multiple nanolayers impuritied on silicon pillars for Si solar cells to pick up photons in ultraviolet and infrared region of solar spectra, in which the localized states originated from nanosilicon doped with oxygen are built to avoid Auger recombination, and some interesting quantum phenomena in the localized states have been observed. The quantum effect of photo-generated carriers has been observed in I-V curve measurement on the photovoltaic sample prepared in oxygen by using nanosecond pulsed laser...
August 3, 2017: Scientific Reports
Lung-Chien Chen, Jia-Ren Wu, Zhong-Liang Tseng, Cheng-Chiang Chen, Sheng Hsiung Chang, Jun-Kai Huang, King-Lien Lee, Hsin-Ming Cheng
This study determines the effects of annealing treatment on the structure and the optical and electronic behaviors of the mixed (FAPbI₃)1-x(MAPbBr₃)x perovskite system. The experimental results reveal that (FAPbI₃)1-x(MAPbBr₃)x (x ~ 0.2) is an effective light-absorbing material for use in inverted planar perovskite solar cells owing to its large absorbance and tunable band gap. Therefore, good band-matching between the (FAPbI₃)1-x(MAPbBr₃)x and C60 in photovoltaic devices can be controlled by annealing at various temperatures...
September 3, 2016: Materials
Wen-Jeng Ho, Ruei-Siang Sue, Jian-Cheng Lin, Hong-Jang Syu, Ching-Fuh Lin
This paper reports impressive improvements in the optical and electrical performance of metal-oxide-semiconductor (MOS)-structure silicon solar cells through the incorporation of plasmonic indium nanoparticles (In-NPs) and an indium-tin-oxide (ITO) electrode with periodic holes (perforations) under applied bias voltage. Samples were prepared using a plain ITO electrode or perforated ITO electrode with and without In-NPs. The samples were characterized according to optical reflectance, dark current voltage, induced capacitance voltage, external quantum efficiency, and photovoltaic current voltage...
August 10, 2016: Materials
Wen-Jeng Ho, Jian-Cheng Lin, Jheng-Jie Liu, Chien-Wu Yeh, Hong-Jhang Syu, Ching-Fuh Lin
In this study, we sought to improve the light trapping of textured silicon solar cells using the plasmonic light scattering of indium nanoparticles (In NPs) of various dimensions. The light trapping modes of textured-silicon surfaces with and without In NPs were investigated at an angle of incidence (AOI) ranging from 0° to 75°. The optical reflectance, external quantum efficiency (EQE), and photovoltaic performance were first characterized under an AOI of 0°. We then compared the EQE and photovoltaic current density-voltage (J-V) as a function of AOI in textured silicon solar cells with and without In NPs...
July 1, 2017: Materials
Wen-Jeng Ho, Jian-Cheng Lin, Jheng-Jie Liu, Wen-Bin Bai, Hung-Pin Shiao
This study characterized the electrical and optical properties of single-junction GaAs solar cells coated with antireflective layers of silicon dioxide (SiO₂), indium tin oxide (ITO), and a hybrid layer of SiO₂/ITO applied using Radio frequency (RF) sputtering. The conductivity and transparency of the ITO film were characterized prior to application on GaAs cells. Reverse saturation-current and ideality factor were used to evaluate the passivation performance of the various coatings on GaAs solar cells...
June 26, 2017: Materials
Shusei Inaba, Varun Vohra
Polymer solar cells (PSCs) are considered as one of the most promising low-cost alternatives for renewable energy production with devices now reaching power conversion efficiencies (PCEs) above the milestone value of 10%. These enhanced performances were achieved by developing new electron-donor (ED) and electron-acceptor (EA) materials as well as finding the adequate morphologies in either bulk heterojunction or sequentially deposited active layers. In particular, producing adequate vertical concentration gradients with higher concentrations of ED and EA close to the anode and cathode, respectively, results in an improved charge collection and consequently higher photovoltaic parameters such as the fill factor...
May 9, 2017: Materials
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