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Fan C, Molayem M, Springborg M, Kick M, Feng Y. Role of the Backbone when Optimizing Functional Groups─A Theoretical Study Based on an Improved Inverse-Design Approach. J Phys Chem A 2022; 126:1289-1299. [PMID: 35166555 DOI: 10.1021/acs.jpca.1c10437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present an improved inverse-design approach for automatically identifying molecular (or other) systems with optimal values for prechosen properties. The new approach uses SMILES (simplified molecular input line entry system) to describe molecular structures efficiently, a genetic algorithm to optimize the molecules automatically, and the DFTB+ (self-consistent charge density functional tight-binding) method to calculate electronic properties. Thereby, almost every class of materials─even macromolecules or monomers─can be studied easily. Without crossover operators but with only mutation operators, the genetic algorithm is more adaptive to SMILES while keeping its efficiency. DFTB+ is more accurate than the DFTB method used in our previous inverse-design approach for the study of excited states and charge transfer processes. The improved approach is applied to optimize benzene, pyridine, pyridazine, pyrimidine, and pyrazine derivatives for seven electronic properties, which all are highly relevant and important for the performance of molecules in solar cells. We found that for some electronic properties, the precise composition and structure of the backbone have remarkable impacts on the value of the electronic properties and/or on the set of functional groups that leads to the best performance. On the contrary, for other properties, these effects are less pronounced. The reasonable optimal functional groups and/or substitution patterns are reported.
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Affiliation(s)
- Chencheng Fan
- Department of Physical and Theoretical Chemistry, University of Saarland, 66123 Saarbrücken, Germany
| | - Mohammad Molayem
- Department of Physical and Theoretical Chemistry, University of Saarland, 66123 Saarbrücken, Germany
| | - Michael Springborg
- Department of Physical and Theoretical Chemistry, University of Saarland, 66123 Saarbrücken, Germany
| | - Moritz Kick
- Fraunhofer Institute for Solar Energy Systems ISE, 79110 Freiburg, Germany
| | - Yaqing Feng
- School of Chemical Engineering and Technology, Tianjin University, 300350 Tianjin, P. R. China
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2
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Wu CJ, Chen YY, Wang CJ, Shiu GY, Huang CH, Liu HJ, Chen H, Lin YS, Lin CF, Han J. Anisotropic properties of pipe-GaN distributed Bragg reflectors. NANOSCALE ADVANCES 2020; 2:1726-1732. [PMID: 36132299 PMCID: PMC9419737 DOI: 10.1039/c9na00743a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 03/23/2020] [Indexed: 06/15/2023]
Abstract
We report here a simple and robust process to convert periodic Si-doped GaN/undoped-GaN epitaxial layers into a porous-GaN/u-GaN distributed Bragg reflector (DBR) structure and demonstrate its material properties in a high-reflectance epitaxial reflector. Directional pipe-GaN layers with anisotropic optical properties were formed from n+-GaN : Si layers in a stacked structure through a lateral and doping-selective electrochemical etching process. Central wavelengths of the polarized reflectance spectra were measured to be 473 nm and 457 nm for the pipe-GaN reflector when the direction of the linear polarizer was along and perpendicular to the pipe-GaN structure. The DBR reflector with directional pipe-GaN layers has the potential for a high efficiency polarized light source and vertical cavity surface emitting laser applications.
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Affiliation(s)
- Chia-Jung Wu
- Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University Taichung, 145 Xingda Rd., South Dist. Taichung 402 Taiwan
| | - Yi-Yun Chen
- Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University Taichung, 145 Xingda Rd., South Dist. Taichung 402 Taiwan
| | - Cheng-Jie Wang
- Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University Taichung, 145 Xingda Rd., South Dist. Taichung 402 Taiwan
| | - Guo-Yi Shiu
- Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University Taichung, 145 Xingda Rd., South Dist. Taichung 402 Taiwan
| | - Chin-Han Huang
- Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University Taichung, 145 Xingda Rd., South Dist. Taichung 402 Taiwan
| | - Heng-Jui Liu
- Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University Taichung, 145 Xingda Rd., South Dist. Taichung 402 Taiwan
| | - Hsiang Chen
- Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University No.1, University Rd., Puli Township Nantou 545 Taiwan
| | - Yung-Sen Lin
- Department of Chemical Engineering, Feng Chia University Seatwen Taichung 407 Taiwan
| | - Chia-Feng Lin
- Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, Research Center for Sustainable Energy and Nanotechnology, National Chung Hsing University Taichung, 145 Xingda Rd., South Dist. Taichung 402 Taiwan
| | - Jung Han
- Department of Electrical Engineering, Yale University 15 Prospect St New Haven Connecticut 06511 USA
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Angular Dependence of Photonic Crystal Coupled to Photovoltaic Solar Cell. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10051574] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Photonic crystals have the advantage of minimizing thermal losses from solar cells, reflecting the solar radiation that is not absorbed by the photovoltaic device. To optimize this optical response, photonic crystals are designed considering the relative position of the Bragg peak and the bandgap of the solar cell, under normal incident irradiation conditions. The aim of this research article was to determine experimentally the optical limits of a solar cell coupled to a photonic crystal acting as beam splitter. For that purpose, the photovoltaic system was characterized under indoor and outdoor conditions; angular dependence of the irradiation source was determined in each case, and both results were compared with good agreement. Moreover, other parameters such as irradiation spectrum and polarization of the light were investigated. The main conclusion is that photovoltaic performance is highly affected by the Bragg peak shifting and the profile is distorted, due to the angular dependence with the sun. These experimental limits must be considered at the early design stage to avoid performance losses.
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Singh BK, Bijalwan A, Rastogi V. Enhancement of light harvesting efficiency of perovskite solar cells by using one-dimensional photonic crystals. APPLIED OPTICS 2019; 58:8046-8054. [PMID: 31674359 DOI: 10.1364/ao.58.008046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 09/07/2019] [Indexed: 06/10/2023]
Abstract
We present methyl-ammonium lead iodide perovskite solar cells coupled with one-dimensional photonic crystals (PCs) to achieve enhancement in light harvesting and photocurrent efficiencies. The introduction of PCs as a light reflection layer in the solar cells attributes to the increase in light harvesting efficiency and photocurrent density, which can be tuned by controlling the PC parameters such as the number of layers and layer thickness. Another important feature of the design is the introduction of a thin Au/Ag layer on top, which lets through more than 70% sunlight incident on it into the device, protects the hole transporting layer, and also helps in containing the light reflected from the PC layer into the device for further harvesting. The effects of layer thickness of the perovskite, hole transporting, and metallic contact layers on solar absorption enhancement and photocurrent density are also studied to achieve high power conversion efficiencies. We propose the optimum structural parameters of the considered solar cell structures, which provide the required guidance and also give further opportunities in the design of organo-metal halide perovskite solar cells coupled with PC structures.
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SAITO H, AOKI D, MAGAINO S, TAKAGI K, HAYASE S. Performance Evaluation Method of Organic Photovoltaics under Indoor Light Condition. ELECTROCHEMISTRY 2018. [DOI: 10.5796/electrochemistry.18-00027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Hidenori SAITO
- Kanagawa Institute of Industrial Scientific and Technology (KISTEC)
- Kyushu Institute of Technology
| | - Daisuke AOKI
- Kanagawa Institute of Industrial Scientific and Technology (KISTEC)
| | - Shinichi MAGAINO
- Kanagawa Institute of Industrial Scientific and Technology (KISTEC)
| | - Katsuhiko TAKAGI
- Research Association Technology Innovation of Organic Photovoltaics (RATO)
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Baek S, Ha SJ, Lee H, Kim K, Kim D, Moon JH. Monolithic Two-Dimensional Photonic Crystal Reflectors for the Fabrication of Highly Efficient and Highly Transparent Dye-Sensitized Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2017; 9:37006-37012. [PMID: 29022691 DOI: 10.1021/acsami.7b09885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The transparent characteristic of dye-sensitized solar cells (DSCs) makes them suitable for building integrated photovoltaic (BIPV) devices. However, the diffusive scattering layer, which is usually used to increase the efficiency of these devices, greatly lowers the transparency of the DSC. This paper described a two-dimensional (2D) photonic crystal (PC) reflector with a sub-micrometer characteristic length that can improve the efficiency of these devices while maintaining transparency. This 2D PCs were fabricated directly onto TiO2 photoelectrodes using colloidal lithography and have the structure of a nanopillar array. A nanopillar with a height of 430 nm was observed to selectively reflect up to 40% of the light of 400-500 nm wavelength. The perceived transparency of the 2D PC electrode was 52%, which is much higher than 0.3% of the conventional scattering layer. The DSC fabricated using the 2D PC electrode demonstrated a maximum photon-to-electric conversion efficiency of 8.23%, which is 18% higher than the pristine electrode. The 2D PC is a highly efficient and wavelength-selective reflector that can be applied to various photoelectric conversion devices.
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Affiliation(s)
- Sujin Baek
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering, Sogang University , 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Su-Jin Ha
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering, Sogang University , 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Heechul Lee
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering, Sogang University , 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Kiwon Kim
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering, Sogang University , 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Dongchoul Kim
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering, Sogang University , 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Jun Hyuk Moon
- Department of Chemical and Biomolecular Engineering and ‡Department of Mechanical Engineering, Sogang University , 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
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7
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Chen CY, Jian ZH, Huang SH, Lee KM, Kao MH, Shen CH, Shieh JM, Wang CL, Chang CW, Lin BZ, Lin CY, Chang TK, Chi Y, Chi CY, Wang WT, Tai Y, Lu MD, Tung YL, Chou PT, Wu WT, Chow TJ, Chen P, Luo XH, Lee YL, Wu CC, Chen CM, Yeh CY, Fan MS, Peng JD, Ho KC, Liu YN, Lee HY, Chen CY, Lin HW, Yen CT, Huang YC, Tsao CS, Ting YC, Wei TC, Wu CG. Performance Characterization of Dye-Sensitized Photovoltaics under Indoor Lighting. J Phys Chem Lett 2017; 8:1824-1830. [PMID: 28387117 DOI: 10.1021/acs.jpclett.7b00515] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE. Therefore, we use an illuminometer as a prime standard with a spectroradiometer to quantify the intensity of indoor lighting and adopt the reverse-biased current-voltage (I-V) characteristics as an indicator to qualify the I-V sampling time for dye-sensitized photovoltaics. The recommendations can brighten the prospects of emerging photovoltaics for indoor applications.
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Affiliation(s)
| | | | | | | | - Ming-Hsuan Kao
- National Nano Device Laboratories, Institute of Electro-Optical Engineering, National Chiao Tung University , Hsinchu 30078, Taiwan, R.O.C
| | - Chang-Hong Shen
- National Nano Device Laboratories, Institute of Electro-Optical Engineering, National Chiao Tung University , Hsinchu 30078, Taiwan, R.O.C
| | - Jia-Min Shieh
- National Nano Device Laboratories, Institute of Electro-Optical Engineering, National Chiao Tung University , Hsinchu 30078, Taiwan, R.O.C
| | - Chin-Li Wang
- Department of Applied Chemistry, National Chi Nan University , Nantou 54561, Taiwan, R.O.C
| | - Chiung-Wen Chang
- Department of Applied Chemistry, National Chi Nan University , Nantou 54561, Taiwan, R.O.C
| | - Bo-Zhi Lin
- Department of Applied Chemistry, National Chi Nan University , Nantou 54561, Taiwan, R.O.C
| | - Ching-Yao Lin
- Department of Applied Chemistry, National Chi Nan University , Nantou 54561, Taiwan, R.O.C
| | | | | | - Cheng-Yu Chi
- Department of Chemical Engineering, National Taiwan University of Science and Technology , Taipei 106, Taiwan, R.O.C
| | - Wei-Ting Wang
- Department of Chemical Engineering, National Taiwan University of Science and Technology , Taipei 106, Taiwan, R.O.C
| | - Yian Tai
- Department of Chemical Engineering, National Taiwan University of Science and Technology , Taipei 106, Taiwan, R.O.C
| | - Ming-De Lu
- Green Energy and Environment Research Laboratories, Industrial Technology Research Institute , Hsinchu 31040, Taiwan, R.O.C
| | - Yung-Liang Tung
- Green Energy and Environment Research Laboratories, Industrial Technology Research Institute , Hsinchu 31040, Taiwan, R.O.C
| | - Po-Ting Chou
- Institute of Chemistry, Academia Sinica , Taipei 115, Taiwan, R.O.C
| | - Wen-Ti Wu
- Institute of Chemistry, Academia Sinica , Taipei 115, Taiwan, R.O.C
| | - Tahsin J Chow
- Institute of Chemistry, Academia Sinica , Taipei 115, Taiwan, R.O.C
| | | | | | | | | | | | | | - Miao-Syuan Fan
- Department of Chemical Engineering and Institute of Polymer Science and Engineering, National Taiwan University , Taipei 10617, Taiwan, R.O.C
| | - Jia-De Peng
- Department of Chemical Engineering and Institute of Polymer Science and Engineering, National Taiwan University , Taipei 10617, Taiwan, R.O.C
| | - Kuo-Chuan Ho
- Department of Chemical Engineering and Institute of Polymer Science and Engineering, National Taiwan University , Taipei 10617, Taiwan, R.O.C
| | - Yu-Nan Liu
- Department of Electrical Engineering, National Kaohsiung University of Applied Sciences , Kaohsiung 807, Taiwan, R.O.C
| | - Hsiao-Yi Lee
- Department of Electrical Engineering, National Kaohsiung University of Applied Sciences , Kaohsiung 807, Taiwan, R.O.C
| | | | | | - Chia-Te Yen
- Institute of Nuclear Energy Research, Atomic Energy Council , Taoyuan 32546, Taiwan, R.O.C
| | - Yu-Ching Huang
- Institute of Nuclear Energy Research, Atomic Energy Council , Taoyuan 32546, Taiwan, R.O.C
| | - Cheng-Si Tsao
- Institute of Nuclear Energy Research, Atomic Energy Council , Taoyuan 32546, Taiwan, R.O.C
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8
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Anaya M, Zhang W, Hames BC, Li Y, Fabregat-Santiago F, Calvo ME, Snaith HJ, Míguez H, Mora-Seró I. Electron injection and scaffold effects in perovskite solar cells. JOURNAL OF MATERIALS CHEMISTRY. C 2017; 5:634-644. [PMID: 28496981 PMCID: PMC5361135 DOI: 10.1039/c6tc04639h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/06/2016] [Indexed: 05/14/2023]
Abstract
In spite of the impressive efficiencies reported for perovskite solar cells (PSCs), key aspects of their working principles, such as electron injection at the contacts or the suitability of the utilization of a specific scaffold layer, are not yet fully understood. Increasingly complex scaffolds attained by the sequential deposition of TiO2 and SiO2 mesoporous layers onto transparent conducting substrates are used to perform a systematic characterization of both the injection process at the electron selective contact and the scaffold effect in PSCs. By forcing multiple electron injection processes at a controlled sequence of perovskite-TiO2 interfaces before extraction, interfacial injection effects are magnified and hence characterized in detail. An anomalous injection behavior is observed, the fingerprint of which is the presence of significant inductive loops in the impedance spectra with a magnitude that correlates with the number of interfaces in the scaffold. Analysis of the resistive and capacitive behavior of the impedance spectra indicates that the scaffolds could hinder ion migration, with positive consequences such as lowering the recombination rate and implications for the current-potential curve hysteresis. Our results suggest that an appropriate balance between these advantageous effects and the unavoidable charge transport resistive losses introduced by the scaffolds will help in the optimization of PSC performance.
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Affiliation(s)
- Miguel Anaya
- Instituto de Ciencia de Materiales de Sevilla , CSIC-US , Avenida Américo Vespucio s/n , Isla de La Cartuja , 41092 , Sevilla , Spain .
| | - Wei Zhang
- Department of Physics , University of Oxford , Clarendon Laboratory , Parks Road , Oxford , X1 3PU , UK .
- School of Chemistry , University of Lincoln , Beevor Street , Lincoln LN6 7DL , UK
| | - Bruno Clasen Hames
- Institute of Advanced Materials (INAM) , Universitat Jaume I , 12006 Castelló , Spain .
| | - Yuelong Li
- Instituto de Ciencia de Materiales de Sevilla , CSIC-US , Avenida Américo Vespucio s/n , Isla de La Cartuja , 41092 , Sevilla , Spain .
| | | | - Mauricio E Calvo
- Instituto de Ciencia de Materiales de Sevilla , CSIC-US , Avenida Américo Vespucio s/n , Isla de La Cartuja , 41092 , Sevilla , Spain .
| | - Henry J Snaith
- Department of Physics , University of Oxford , Clarendon Laboratory , Parks Road , Oxford , X1 3PU , UK .
| | - Hernán Míguez
- Instituto de Ciencia de Materiales de Sevilla , CSIC-US , Avenida Américo Vespucio s/n , Isla de La Cartuja , 41092 , Sevilla , Spain .
| | - Iván Mora-Seró
- Institute of Advanced Materials (INAM) , Universitat Jaume I , 12006 Castelló , Spain .
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9
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Venkatraman V, Abburu S, Alsberg BK. Artificial evolution of coumarin dyes for dye sensitized solar cells. Phys Chem Chem Phys 2016; 17:27672-82. [PMID: 26428071 DOI: 10.1039/c5cp04624f] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The design and discovery of novel molecular structures with optimal properties has been an ongoing effort for materials scientists. This field has in general been dominated by experiment driven trial-and-error approaches that are often expensive and time-consuming. Here, we investigate if a de novo computational design methodology can be applied to the design of coumarin-based dye sensitizers with improved properties for use in Grätzel solar cells. To address the issue of synthetic accessibility of the designed compounds, a fragment-based assembly is employed, wherein the combination of chemical motifs (derived from the existing databases of structures) is carried out with respect to user-adaptable set of rules. Rather than using computationally intensive density functional theory (DFT)/ab initio methods to screen candidate dyes, we employ quantitative structure-property relationship (QSPR) models (calibrated from empirical data) for rapid estimation of the property of interest, which in this case is the product of short circuit current (Jsc) and open circuit voltage (Voc). Since QSPR models have limited validity, pre-determined applicability domain criteria are used to prevent unacceptable extrapolation. DFT analysis of the top-ranked structures provides supporting evidence of their potential for dye sensitized solar cell applications.
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Affiliation(s)
- Vishwesh Venkatraman
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
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10
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Labelle AJ, Thon SM, Masala S, Adachi MM, Dong H, Farahani M, Ip AH, Fratalocchi A, Sargent EH. Colloidal quantum dot solar cells exploiting hierarchical structuring. NANO LETTERS 2015; 15:1101-1108. [PMID: 25547345 DOI: 10.1021/nl504086v] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Extremely thin-absorber solar cells offer low materials utilization and simplified manufacture but require improved means to enhance photon absorption in the active layer. Here, we report enhanced-absorption colloidal quantum dot (CQD) solar cells that feature transfer-stamped solution-processed pyramid-shaped electrodes employed in a hierarchically structured device. The pyramids increase, by up to a factor of 2, the external quantum efficiency of the device at absorption-limited wavelengths near the absorber band edge. We show that absorption enhancement can be optimized with increased pyramid angle with an appreciable net improvement in power conversion efficiency, that is, with the gain in current associated with improved absorption and extraction overcoming the smaller fractional decrease in open-circuit voltage associated with increased junction area. We show that the hierarchical combination of micron-scale structured electrodes with nanoscale films provides for an optimized enhancement at absorption-limited wavelengths. We fabricate 54.7° pyramid-patterned electrodes, conformally apply the quantum dot films, and report pyramid CQD solar cells that exhibit a 24% improvement in overall short-circuit current density with champion devices providing a power conversion efficiency of 9.2%.
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Affiliation(s)
- André J Labelle
- Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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11
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Guo M, Xie K, Liu X, Wang Y, Zhou L, Huang H. A strategy to reduce the angular dependence of a dye-sensitized solar cell by coupling to a TiO2 nanotube photonic crystal. NANOSCALE 2014; 6:13060-13067. [PMID: 25247717 DOI: 10.1039/c4nr03712j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Almost all types of solar cells suffer from a decreased power output when the incident light is tilted away from normal since the incident intensity generally follows a cosine law of the incident angle. Making use of the blue shift nature of the Bragg position of a TiO2 nanotube photonic crystal (NT PC) under oblique incidence, we demonstrate experimentally that the use of the NT PC can partially compensate the cosine power loss of a dye-sensitized solar cell (DSSC). The strategy used here is to purposely choose the Bragg position of the NT PC to be at the longer wavelength side of the dye absorption peak. When the incident light is tilted, the blue shift of the Bragg position results in more overlap with the dye absorption peak, generating a higher efficiency that partially compensates the reduced photon flux due to light inclination. Moreover, the unique structure of the vertically aligned TiO2 nanotubes contributes an additional scattering effect when the incident light is tilted. As a result, the power output of a DSSC coupled with the NT PC layer shows a much flatter angular dependence than a DSSC without the NT PC. At all the incident angles, the DSSC coupled with the NT PC layer also shows a higher power conversion efficiency than the one without. The concept of using NT PC to mitigate the angular dependence of DSSCs can be easily extended to many other optoelectronic devices that are irradiance sensitive.
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Affiliation(s)
- Min Guo
- Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hong Kong, China.
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12
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López-López C, Colodrero S, Míguez H. Panchromatic porous specular back reflectors for efficient transparent dye solar cells. Phys Chem Chem Phys 2014; 16:663-8. [PMID: 24263620 PMCID: PMC3894859 DOI: 10.1039/c3cp53939c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A panchromatic specular reflector that mimics the reflection properties of a standard diffuse scattering layer in a broad spectral range within the visible is coupled to a dye sensitized nanocrystalline titania electrode to attain a solar cell of largely enhanced efficiency that, at the same time, preserves its transparency.
A panchromatic specular reflector based dye solar cell is presented herein. Photovoltaic performance of this novel design is compared to that of cells in which standard diffuse scattering layers are integrated. The capability of the proposed multilayer structures to both emulate the broad band reflection of diffuse scattering layers of standard thickness (around 5 microns) and give rise to similarly high light harvesting and power conversion efficiencies, yet preserving the transparency of the device, is demonstrated. Such white light reflectors are comprised of stacks of different porous optical multilayers, each one displaying a strong reflection in a complementary spectral range, and are designed to leave transmittance unaltered in a narrow red-frequency range in which the sensitized electrode shows negligible absorption, thus allowing us to see through the cell. The reflectance bandwidth achieved is three times as broad as the largest bandwidth previously achieved using any photonic structure integrated into a dye solar cell.
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Affiliation(s)
- Carmen López-López
- Multifunctional Optical Materials Group, Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla (US-CSIC), Américo Vespucio 49, 41092 Sevilla, Spain.
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13
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Venkatraman V, Åstrand PO, Alsberg BK. Quantitative structure-property relationship modeling of Grätzel solar cell dyes. J Comput Chem 2013; 35:214-26. [PMID: 24222335 DOI: 10.1002/jcc.23485] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 10/04/2013] [Accepted: 10/11/2013] [Indexed: 11/05/2022]
Abstract
With fossil fuel reserves on the decline, there is increasing focus on the design and development of low-cost organic photovoltaic devices, in particular, dye-sensitized solar cells (DSSCs). The power conversion efficiency (PCE) of a DSSC is heavily influenced by the chemical structure of the dye. However, as far as we know, no predictive quantitative structure-property relationship models for DSSCs with PCE as one of the response variables have been reported. Thus, we report for the first time the successful application of comparative molecular field analysis (CoMFA) and vibrational frequency-based eigenvalue (EVA) descriptors to model molecular structure-photovoltaic performance relationships for a set of 40 coumarin derivatives. The results show that the models obtained provide statistically robust predictions of important photovoltaic parameters such as PCE, the open-circuit voltage (V(OC)), short-circuit current (J(SC)) and the peak absorption wavelength λ(max). Some of our findings based on the analysis of the models are in accordance with those reported in the literature. These structure-property relationships can be applied to the rational structural design and evaluation of new photovoltaic materials.
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Affiliation(s)
- Vishwesh Venkatraman
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway
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