Letter Cite This: ACS Appl. Energy Mater. XXXX, XXX, XXX−XXX
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High-Performance Monolithic Photovoltaic−Thermoelectric Hybrid Power Generator Using an Exothermic Reactive Interlayer Yong Jun Kim,† Hyeongdo Choi,† Choong Sun Kim,† Gyusoup Lee,† Seongho Kim,† Jiwon Park,† Seong Eun Park,‡ and Byung Jin Cho*,† †
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School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea ‡ Solar Energy Laboratory, Korea Institute of Energy Research, 140 Yuseong-daero, 1312 Beon-gil, Yuseong-gu, Daejeon 31401, Republic of Korea S Supporting Information *
ABSTRACT: A high-performance monolithic photovoltaic− thermoelectric hybrid generator with a photothermal conversion layer is introduced. The layer, a thin acrylic film dyed with black colored AZO dye, effectively absorbs photons in the near-infrared region. The AZO dye supports an exothermic reaction through nonradiative relaxation. The hybrid generator was fabricated through monolithic integration. A thermoelectric (TE) module was fabricated directly on the back surface of the photovoltaic (PV) module without using the ceramic substrate typically employed in conventional TE modules, so that thermal resistance between the PV module and TE module could be minimized. The 51.35 cm2 fabricated hybrid generator showed a power conversion efficiency of about 22.5% with an open-circuit voltage of 0.94 V and a maximum power of 1.15 W under standard AM 1.5G illumination. The hybrid power generator with the photothermal conversion layer showed about 40% higher output power compared to the control PV only, about 16% higher than an acrylic control film, and about 7.4% higher than a common black dyed interface layer. KEYWORDS: photovoltaic−thermoelectric hybrid generator, photothermal conversion layer, exothermic reactive interlayer, monolithic, AZO dye, solution process
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//GaInAsP/GaInAs wafer bonded four-junction cell fabricated by Fraunhofer in 2014.15 Unlike the c-Si-based PV module, III−V group compounds are capable of absorbing a wide range of photons with easy band gap engineering. However, the process is relatively complicated, and the materials used in their manufacture are rare, which makes them cost-ineffective and not suited for mass production. Another approach involves integrating photovoltaic and thermoelectric power generators to make a hybrid PV-TE generator. This configuration allows almost the full spectrum of solar energy to be utilized. It also helps reduce PCE degradation in PV modules caused by highenergy photons and high cell temperature.9,16−19 In a PV-TE hybrid generator, a high-efficiency c-Si PV module and a TEG are structurally hybridized, so that energy from the visible region is harvested by the PV module and energy from the near-infrared region is harvested by the TEG. Several recent studies have demonstrated the feasibility of this concept. Park et al. combined a commercial TEG with a c-Si
he crystalline silicon (c-Si) photovoltaic (PV) module has multiple advantages, including high power conversion efficiency (PCE), reliability, and easy processing with the aid of conventional silicon technology, compared to other solar energy harvesters.1,2 The Institute for Solar Energy Research Hamelin (ISFH) succeeded in fabricating PV modules with a PCE of 26.1% using single crystalline Si in 2018.3 Kaneka Corp. in Japan successfully implemented a c-Si heterostructure PV module with a conversion efficiency of 26.6% in 2016.4 Many researchers continue to try to further increase the PCE of c-Si PV modules by various techniques such as surface nanostructuring and texturization.5−7 However, PCE is limited by the intrinsic nature of the c-Si PV modules, which use Si as the main body for electron−hole pairs generation.8−10 The band gap energy of Si is about 1.12 eV at 300 K, and theoretically it cannot absorb photons with a wavelength longer than 1100 nm. Yet photons with wavelengths greater than 1100 nm account for about 40% of the total solar energy irradiated on the earth. In order to overcome the limitations of PCE, it is important to utilize the photons in the longwavelength region for energy harvesting.11−14 The PV module with the current highest PCE implemented with this full-spectrum utilization concept is the GaInP/GaAs © XXXX American Chemical Society
Received: January 4, 2019 Accepted: March 11, 2019 Published: March 11, 2019 A
DOI: 10.1021/acsaem.9b00011 ACS Appl. Energy Mater. XXXX, XXX, XXX−XXX
Letter
ACS Applied Energy Materials
Figure 1. Schematic image of a photothermal conversion assisted monolithic photovoltaic−thermoelectric (PV-TE) hybrid generator. The photons in the near-infrared (near-IR) region passing through the crystalline silicon PV module are absorbed by the photothermal conversion layer. Because TEG does not have a ceramic substrate, more heat energy can be used for power generation.
Figure 2. (a) Photographs and (b) surface temperature measurement results of the acrylic film (Control), acrylic film dyed with common black colored dye (Black), and photothermal conversion layer dyed with AZO dye (AZO). The insets show scanning electron microscopic (SEM) images. Left and right insets denote the top and cross-sectional views of each film, respectively. Surface temperature measurements were performed using a FLIR pyrometer under standard AM 1.5G illumination. (c) Surface temperature transition of each film according to time.
selective solar absorber (SSA) using a superlattice structure as the interface layer;23 however, it requires a complicated and costly process which is not practical for commercialization. In this work, a monolithic integrated large-area PV-TE hybrid generator without a ceramic substrate between the two modules is introduced. More importantly, in this design a photothermal conversion layer has been inserted between the PV module and the TEG, which absorbs long-wavelength photons to generate heat. This allows the TEG to harvest more electrical energy by utilizing a larger amount of heat energy. Figure 1 shows a schematic drawing of the structure of the fabricated monolithic PV-TE hybrid generator. The desirable properties of the interface layer between the PV module and the TEG include the following.
PV module and fabricated a two-terminal (series connected) hybrid generator to achieve a maximum power of 65.2 mW and a PCE of 16.3% under standard AM 1.5G illumination.20 Kossyvakis et al. experimentally demonstrated a hybrid generator that harvested 22.5% higher power than a PV module at a cell operating temperature of only about 80 °C.9 Beyond these, some studies have reported increases in the PCE of the PV-TE hybrid generator using a solar spectrum splitter or concentrator.18,21,22 In these studies, however, a thick ceramic substrate was located between the PV module and TEG: the commercial TEG was simply attached to the back surface of the PV module using thermal paste. In addition, an interface layer between two modules, which enables photons in the long-wavelength region to be effectively absorbed, was commonly absent. AL-Rjoub et al. have reported the use of a B
DOI: 10.1021/acsaem.9b00011 ACS Appl. Energy Mater. XXXX, XXX, XXX−XXX
Letter
ACS Applied Energy Materials
Figure 3. (a) Near-IR spectrophotometric analysis result of the films. (b) Basic mechanisms of the one photon absorption (left) and two photon absorption (right). (c) FT-IR spectrometric analysis results showing that the AZO dye polymeric molecules were chemically bonded to acrylic chains. (d) Results of the intensity observation of photoluminescence (PL) for a 1064 nm wavelength light source showing that the AZO dye generates heat through nonradiative relaxation.
through nonradiative relaxation to the acrylic chain in the form of heat and eventually to the TEG. Figure 2a shows a normal acrylic film, an acrylic film dyed with common black colored dye and a photothermal conversion layer dyed with AZO dye. The dyeing was accomplished with a process using a dye solution. The scanning electron microscope−back scattered electrons (SEMBSE) cross-section image (inset) shows that about a 1 μm thick layer of AZO dye is uniformly coated on the surface of the acrylic film. Figure 2b shows the photothermal conversion performance of each film. Standard AM 1.5G illumination was irradiated on each film using a solar simulator, and the surface temperature was measured using a FLIR pyrometer, when the temperature reached a steady state after irradiation. The ambient temperature of the measurement room was maintained at 25 °C. The surface temperatures of the normal acrylic film, the film dyed with common black colored dye, and AZO dyed photothermal conversion layer increased to about 31, 40, and 55 °C. As can be seen, the photothermal conversion efficiency was significantly enhanced by the AZO dye coating, applied by a simple solution process on normal acrylic film. Figure 3 shows the results of an analysis explaining why the AZO dyed photothermal conversion layer has superb photon absorption and heat generation performance. A near-IR spectrophotometric analysis was performed to see how well each film can absorb photons from the near-IR region, and the results are shown in Figure 3a. Both the transparent normal acrylic film and black dyed acrylic film have decidedly low spectral absorptivity in the near-IR region. However, the AZO dyed acrylic film has a high absorptivity of about 0.6 in the wavelength range near 900 nm and an average 0.5 over the entire region. Previously, it has been proven that a black colored thermal and electrical conductive material, which has been the
(1) Since the TEG’s thick ceramic substrates were removed to minimize parasitic thermal resistance, the interface layer should provide electrical insulation to avoid electrode shorting. (2) The thermal resistance of the interface layer should be as low as possible so that the temperature gradient across the interface is negligible. (3) It should be able to absorb photons from the nearinfrared (near-IR) region and generate heat effectively by exothermic reaction. (4) It should have a simple and cost-effective manufacturing process so that it is suitable for mass production. As a base material for the interfacial layer in this experiment, a very thin (5 μm thick) acrylic film was used to achieve electrical insulation as well as to minimize thermal resistance. Thermal resistance, RTh, is defined by the following eq 1. t RTh = (1) κA where t is the material thickness in a direction parallel to the heat flow, κ is the thermal conductivity, and A is the area. Acrylic has a thermal conductivity of about 0.2 W·m−1·K−1 at room temperature. The acrylic film was dyed with black AZO dye to satisfy the third and fourth properties mentioned above. Black AZO dye is a black colored cationic dye which is one of the most appropriate dyes to conformally coat orlontype acrylic with acid group exhaust position (nitrile group, -CN). Unlike other typical black colored dye, it has NN double bonds. (See Supporting Information Figures S1 and S2.) The name azo comes from azote, the French name for nitrogen. Ultraviolet (UV) and visible photons in sunlight radiation are absorbed in the PV module, and photons in the near-IR region penetrate the PV module. Then they are effectively absorbed by the photothermal conversion layer (the AZO dyed acrylic film). The absorbed energy is transferred C
DOI: 10.1021/acsaem.9b00011 ACS Appl. Energy Mater. XXXX, XXX, XXX−XXX
Letter
ACS Applied Energy Materials
Figure 4. (a) Photograph of the actual fabricated monolithic hybrid generator (top) and the substrate-less TEG module (below). (b) Schematic drawing of the measurement setup. (c) Current−voltage and (d) power−voltage measurement results of the PV only and the hybrid generators with three different interfacial layers.
preferred interface layer in the PV-TE hybrid generator, can absorb photons in the visible region well because of its color. More importantly, in a substantial high-performance hybrid generator, the interface layer should preferentially focus on photons in the near-IR region, which penetrate the PV module. Low thermal resistance is required to minimize the temperature difference formed across the interface layer, and electrical insulation is essential to prevent shorts in integration between modules. Therefore, applying photothermal conversion characteristics to a very thin insulating layer using a solution process is a breakthrough to realize high-performance PV-TE hybrid generators. The photons in the near-IR region have relatively low energy, and therefore they are hardly absorbed in the PV module. However, they can be effectively absorbed into the interface layer by using either (1) low band gap polymer or (2) two photon absorption. In the field of polymer-based PV module research, low band gap (ELUMO − EHOMO) materials have been actively developing to improve PCE.24,25 However, several obstacles remain to be solved, such as the inherently low PCE of the material and the low reliability of the module.26,27 The second option, two photon absorption, involves creating a virtual state in the middle of the band gap through the chemical binding of two or more polymers. The virtual state enables two low energy photons to excite simultaneously.28,29 AZO dye with the NN double bond is suited for this purpose and, on the acrylic film, allows the photothermal conversion layer to absorb about twice as many photons as the black dyed film in the near-IR region. The reason for the improved spectral absorptivity of AZO dyed acrylic films was that more low energy photons can be absorbed through two photon absorption. The fact that two photon absorption has become a dominant mechanism in AZO dyed acrylic film can be observed by the trend of
photoluminescence spectra according to incident laser intensity30 (Figure S5). Fourier transform infrared (FT-IR) spectrometric analysis was performed to determine whether the AZO dye polymeric molecules were well chemically bound to the acrylic molecules on the film surface. Before the measurement, the samples were solvent cleaned several times and dried for 2 h after dying. The result is shown in Figure 3c. The analysis of the normal acrylic film showed a C−H stretching frequency of CC double bonds near 3000 cm−1 and a sharp stretching frequency peak of carbonyl group (CO) near 1710 cm−1. Since the basic skeleton of the interface layers was acrylic film, it is natural that chemical binding of acrylic polymeric molecules was detected. The main peaks which can be observed only in the dyed films are three peaks in the vicinity of 1000 cm−1 and one near 1400 cm−1. The former is the result of the functional group of the common black dye compound. The latter is the NN stretching frequency of the AZO dye, whose aromatic ring with the -OCH3 group is bonded to the R′ substituent. When AZO is chemically bound with acrylic, it forms an OCH3 group. The measurement results showed that the stretching frequency of the N double bond when this group is included was detected. Figure 3d shows the observed intensity of photoluminescence (PL) of each film. The polymeric molecules excited by the photons in the near-IR region show PL peaks at different wavelengths depending on the compound structure. In contrast to the normal acrylic film, the photothermal conversion layer confirmed that the AZO dye molecules were chemically bound to both sides of the acrylic film. However, the analysis results showed that the PL spectrum of all the films had a similar tendency. The reason for the similar trends is that the AZO dye absorbs the photons in the near-IR region and then transfers the excited energy to the acrylic chain in the form of heat rather than fluorescence.31 The AZO dye conjugated acrylic polymer absorbs more low energy photons due to the newly generated virtual state inside the band gap. D
DOI: 10.1021/acsaem.9b00011 ACS Appl. Energy Mater. XXXX, XXX, XXX−XXX
Letter
ACS Applied Energy Materials
The maximum output power of the exothermic reaction interlayer assisted PV-TE hybrid generator was 0.32 W higher than that of the PV only. This corresponds to a 22.5% increase in PCE. When using an AZO dyed layer, the output power increased about 16% and 7.4% compared to the control interface layer and the black dyed layer, respectively. The hybrid device generated 22.4 mW·cm−2 density of power and 1.15 W overall power. For PV module, TEG is a voltage source and a resistive element. The fill factor decreased due to the internal resistance of the TEG in the I−V characteristics of the PV-TE hybrid generator. However, the maximum output power increased as the open-circuit voltage generated by the TEG was added to the open-circuit voltage of the PV-TE hybrid generator. The results presented here show that it is feasible to maximize the photothermal conversion performance of the interface layer using a simple solution process, thereby greatly improving the power generation characteristics and practicality of the hybrid generator.
Electrons excited above the LUMO level of the acrylic polymer emit energy through nonradiative relaxation until reaching the LUMO level. In this process, the polymer chain produces heat through vibration and stretching along the chain. Then the electrons fall to the acrylic HOMO level emitting PL. Because of this process, the photothermal conversion layer with the AZO dye incorporated also has the same PL spectra as the normal acrylic film. Inside the chain, the vibrational energy and a part of the PL emitted from the acrylic polymer is transferred to adjacent acrylic monomers, and this process is repeated continuously. Therefore, the fabricated AZO dyed acrylic film can continue the photothermal conversion procedure as long as sunlight exists. The fabricated monolithic large-area PV-TE hybrid generator with an area of 7.9 × 6.5 cm2 is shown in Figure 4a. The surface of the acrylic double sided tape film was dyed with black AZO dye. Then a bifacial c-Si PV module and a TEG were attached using the film. A bifacial PV module was chosen to effectively transfer the remaining photon energy to the TEG after energy conversion to make a clear difference caused by the performance of interface layers. The bifacial PV module used in this work had an open-circuit voltage of about 0.61 V, a short-circuit current of 1.78 A, a PCE of about 16.4%, and a fill factor of about 78% on the n+ side under standard AM 1.5G illumination. The PV module within the hybrid generator was irradiated under standard AM 1.5G illumination, and the output electrical characteristics were measured. The cold side of the monolithic hybrid generator was kept constant at 25 °C using water cooling (See Figure 4b). Panels c and d of Figure 4 show the current−voltage (I−V) and power−voltage (P−V) characteristics measurements of the hybrid generator, respectively. Measurements were carried out on the PV only and hybrid generators with three different types of interface layers. The fabricated TEG was measured to have a Seebeck coefficient of about 18.8 mV·K−1. As the photothermal conversion performance of the interface layer increased, the open-circuit voltage of the PV-TE hybrid generator also increased, as can be seen in Figure 4c. This increased amount of the open-circuit voltage includes a decrease in the PV module caused by temperature coefficient and increase in TEG generated by temperature difference. The negative temperature coefficient in open-circuit voltage of the PV module can be complemented by the aid of open-circuit voltage add-up effect from TEG. This effect is a breakthrough that can greatly increase the overall PCE of the PV-TE hybrid generator. When the TEG was hybridized with the PV module with a control interface layer (normal acrylic film), the open-circuit voltage of the hybrid generator increased about 0.22 V compared to the PV only. For the dyed films, there was an increase of about 0.28 V for the interface layer dyed with common black dye, and about 0.34 V enhancement when the AZO dyed photothermal conversion layer was applied to the generator. From the output voltage, we can deduce the temperature difference across the TEG. This result shows that the AZO dyed photothermal conversion layer created an 18 K temperature difference across the TEG, which is about 6.4 K higher than that of the control acrylic film. Due to the improved photothermal conversion performance, the temperature difference across the TEG has significantly increased. It is encouraging that the open-circuit voltage add-up performance, one of the greatest advantages of the PV-TE hybrid generator, has been greatly improved.
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsaem.9b00011.
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Chemical information on the AZO dye used for the exothermic reaction and the common black dye; color index number; dyes’ distinct chemical properties and usages (PDF)
AUTHOR INFORMATION
Corresponding Author
*(B.J.C.) E-mail:
[email protected]. ORCID
Byung Jin Cho: 0000-0003-3000-5403 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was supported by grants from the National Research Foundation of Korea funded by the Korean government, NRF2015R1A5A1036133 and NRF-2017M1A2A2087348.
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REFERENCES
(1) Kirchartz, T.; Rau, U. What Makes a Good Solar Cell? Adv. Energy Mater. 2018, 8, 1703385. (2) Bahabry, R. R.; Kutbee, A. T.; Khan, S. M.; Sepulveda, A. C.; Wicaksono, I.; Nour, M.; Wehbe, N.; Almislem, A. S.; Ghoneim, M. T.; Torres Sevilla, G. A.; Syed, A.; Shaikh, S. F.; Hussain, M. M. Corrugation Architecture Enabled Ultraflexible Wafer-Scale HighEfficiency Monocrystalline Silicon Solar Cell. Adv. Energy Mater. 2018, 8, 1702221. (3) Haase, F.; Hollemann, C.; Schäfer, S.; Merkle, A.; Rienäcker, M.; Krügener, J.; Brendel, R.; Peibst, R. Laser Contact Openings for Local Poly-Si-Metal Contacts Enabling 26.1%-efficient POLO-IBC Solar Cells. Sol. Energy Mater. Sol. Cells 2018, 186, 184. (4) Yoshikawa, K.; Kawasaki, H.; Yoshida, W.; Irie, T.; Konishi, K.; Nakano, J.; Uto, T.; Adachi, D.; Kanematsu, M.; Uzu, H.; Yamamoto, K. Silicon Heterojunction Solar Cell with Interdigitated Back Contacts for a Photoconversion Efficiency Over 26%. Nat. Energy 2017, 2, 17032. (5) Jiang, Y.; Shen, H.; Pu, T.; Zheng, C.; Tang, Q.; Gao, K.; Wu, J.; Rui, C.; Li, Y.; Liu, Y. High Efficiency Multi-crystalline Silicon Solar Cell with Inverted Pyramid Nanostructure. Sol. Energy 2017, 142, 91. E
DOI: 10.1021/acsaem.9b00011 ACS Appl. Energy Mater. XXXX, XXX, XXX−XXX
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Selective Solar Absorber for High Temperature Applications. Sol. Energy 2018, 172, 177−183. (24) Shi, X.; Zuo, L.; Jo, S.; Gao, K.; Lin, F.; Liu, F.; Jen, A. K.-Y. Design of a Highly Crystalline Low-Band Gap Fused-Ring Electron Acceptor for High-Efficiency Solar Cells with Low Energy Loss. Chem. Mater. 2017, 29, 8369−8376. (25) Yang, D.; Sasabe, H.; Sano, T.; Kido, J. Low-Band-Gap Small Molecule for Efficient Organic Solar Cells with a Low Energy Loss below 0.6 ev and a High Open-circuit Voltage of Over 0.9 V. ACS Energy Lett. 2017, 2, 2021−2025. (26) Lin, D.; Lu, Z.; Hsu, P.-C.; Lee, H. R.; Liu, N.; Zhao, J.; Wang, LH.; Liu, C.; Cui, Y. A High Tap Density Secondary Silicon Particle Anode Fabricated by Scalable Mechanical Pressing for Lithium-ion Batteries. Energy Environ. Sci. 2015, 8, 2371−2376. (27) Wang, C.; Xu, X.; Zhang, W.; Bergqvist, J.; Xia, Y.; Meng, X.; Bini, K.; Ma, W.; Yartsev, A.; Vandewal, K.; Andersson, M.; Inganäs, O.; Fahlman, M.; Wang, W. Low Band Gap Polymer Solar Cells with Minimal Voltage Losses. Adv. Energy Mater. 2016, 6, 1600148. (28) Antonov, L.; Kamada, K.; Nedeltcheva, D.; Ohta, K.; Kamounah, F. S. Gradual Change of One-and Two-photon Absorption Properties in Solution Protonation of 4-N, Ndimethylamino-4’-aminoazobenzene. J. Photochem. Photobiol., A 2006, 181, 274−282. (29) Antonov, L.; Kamada, K.; Ohta, K.; Kamounah, F. A Systematic Femtosecond Study on the Two-Photon Absorbing D-π-A Molecules−π-bridge Nitrogen Insertion and Strength of the Donor and Acceptor Groups. Phys. Chem. Chem. Phys. 2003, 5, 1193−1197. (30) Pawlicki, M.; Collins, H. A.; Denning, R. G.; Anderson, H. L. Two-photon Absorption and the Design of Two-Photon Dyes. Angew. Chem., Int. Ed. 2009, 48, 3244−3266. (31) Maji, S. K.; Sreejith, S.; Joseph, J.; Lin, M.; He, T.; Tong, Y.; Sun, H.; Yu, S. W.-K.; Zhao, Y. Upconversion Nanoparticles as a Contrast Agent for Photoacoustic Imaging in Live Mice. Adv. Mater. 2014, 26, 5633−5638.
(6) Haschke, J.; Seif, J.; Riesen, Y.; Tomasi, A.; Cattin, J.; Tous, L.; Choulat, P.; Aleman, M.; Cornagliotti, E.; Uruena, A.; Russell, R.; Duerinckx, F.; Champliaud, J.; Levrat, J.; Abdallah, A.; Aïssa, B.; Tabet, N.; Wyrsch, N.; Despeisse, M.; Szlufcik, J.; De Wolf, S.; Ballif, C. The Impact of Silicon Solar Cell Architecture and Cell Interconnection on Energy Yield in Hot & Sunny Climates. Energy Environ. Sci. 2017, 10, 1196−1206. (7) Yang, L.; Liu, Y.; Wang, Y.; Chen, W.; Chen, Q.; Wu, J.; Kuznetsov, A.; Du, X. 18.87%-efficient Inverted Pyramid Structured Silicon Solar Cell by One-step Cu-assisted Texturization Technique. Sol. Energy Mater. Sol. Cells 2017, 166, 121. (8) Motiei, P.; Yaghoubi, M.; Goshtashbirad, E.; Vadiee, A. Twodimensional Unsteady State Performance Analysis of a Hybrid Photovoltaic-Thermoelectric Generator. Renewable Energy 2018, 119, 551. (9) Kossyvakis, D.; Voutsinas, G.; Hristoforou, E. Experimental Analysis and Performance Evaluation of a Tandem Photovoltaic− Thermoelectric Hybrid System Energy. Energy Convers. Manage. 2016, 117, 490. (10) Zhu, W.; Deng, Y.; Wang, Y.; Shen, S.; Gulfam, R. Highperformance Photovoltaic-Thermoelectric Hybrid Power Generation System with Optimized Thermal Management. Energy 2016, 100, 91. (11) Xu, Y.; Xuan, Y.; Liu, X. Broadband Photon Management of Subwavelength Structures Surface for Full-spectrum Utilization of Solar Energy Energy. Energy Convers. Manage. 2017, 152, 22. (12) Li, W.; Jin, J.; Wang, H.; Wei, X.; Ling, Y.; Hao, Y.; Pei, G.; Jin, H. Full-spectrum Solar Energy Utilization Integrating Spectral Splitting, Photovoltaics and Methane Reforming. Energy Convers. Manage. 2018, 173, 602. (13) Da, Y.; Xuan, Y.; Li, Q. From Light Trapping to Solar Energy Utilization: A Novel Photovoltaic−Thermoelectric Hybrid System to Fully Utilize Solar Spectrum. Energy 2016, 95, 200. (14) Xu, Y.; Xuan, Y.; Yang, L. Full-spectrum Photon Management of Solar Cell Structures for Photovoltaic−Thermoelectric Hybrid Systems. Energy Convers. Manage. 2015, 103, 533. (15) Dimroth, F.; Grave, M.; Beutel, P.; Fiedeler, U.; Karcher, C.; Tibbits, T.; Oliva, E.; Siefer, G.; Schachtner, M.; Wekkeli, A.; Bett, A.; Krause, R.; Piccin, M.; Blanc, N.; Drazek, C.; Guiot, E.; Ghyselen, B.; Salvetat, T.; Tauzin, A.; Signamarcheix, T.; Dobrich, A.; Hannappel, T.; Schwarzburg, K. Wafer Bonded Four-junction GaInP/GaAs// GaInAsP/GaInAs Concentrator Solar Cells with 44.7% Efficiency. Prog. Photovoltaics 2014, 22, 277−282. (16) Makki, A.; Omer, S.; Su, Y.; Sabir, H. Numerical Investigation of Heat Pipe-based Photovoltaic−Thermoelectric Generator (HPPV/TEG) Hybrid System Energy. Energy Convers. Manage. 2016, 112, 274. (17) Beeri, O.; Rotem, O.; Hazan, E.; Katz, E. A.; Braun, A.; Gelbstein, Y. Hybrid Photovoltaic-Thermoelectric System for Concentrated Solar Energy Conversion: Experimental Realization and Modeling. J. Appl. Phys. 2015, 118, 115104. (18) Li, D.; Xuan, Y.; Li, Q.; Hong, H. Exergy and Energy Analysis of Photovoltaic-Thermoelectric Hybrid Systems. Energy 2017, 126, 343. (19) Xu, L.; Xiong, Y.; Mei, A.; Hu, Y.; Rong, Y.; Zhou, Y.; Hu, B.; Han, H. Efficient Perovskite Photovoltaic-Thermoelectric Hybrid Device. Adv. Energy Mater. 2018, 8, 1702937. (20) Park, K.-T.; Shin, S.-M.; Tazebay, A. S.; Um, H.-D.; Jung, J.-Y.; Jee, S.-W.; Oh, M.-W.; Park, S.-D.; Yoo, B.; Yu, C.; Lee, J.-H. Lossless Hybridization between Photovoltaic and Thermoelectric Devices. Sci. Rep. 2013, 3, 2123. (21) Deng, Y.; Zhu, W.; Wang, Y.; Shi, Y. Enhanced Performance of Solar-driven Photovoltaic−Thermoelectric Hybrid System in an Integrated Design. Sol. Energy 2013, 88, 182. (22) Lamba, R.; Kaushik, S. Modeling and Performance Analysis of a Concentrated Photovoltaic−Thermoelectric Hybrid Power Generation System Energy. Energy Convers. Manage. 2016, 115, 288. (23) AL-Rjoub, A.; Rebouta, L.; Costa, P.; Barradas, N. P.; Alves, E.; Ferreira, P. J.; Abderrafi, K.; Matilainen, A.; Pischow, K. A Design of F
DOI: 10.1021/acsaem.9b00011 ACS Appl. Energy Mater. XXXX, XXX, XXX−XXX
