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Efficiently-designed Hybrid Tandem Photovoltaic with Organic and Inorganic Single Cells
Premkumar Vincent,Jin-Hyuk Bae,김혁 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.9
Conjugated polymers for solar-cell applications have been extensively studied and have proven highly beneficial in tandem solar-cell structures. This study focuses on achieving power conversion efficiencies of greater than 10% when in tandem with a highly efficient copper indium gallium diselenide (CIGS) solar cell. The optimal design is suggested based on the result of optical simulations on the organic-CIGS tandem structure. This is one of the first reports to show theoretically an organic-CIGS tandem solar cell to obtain an efficiency of greater than 10%. The best PCE was at a thickness of 200 nm for PTB7:PCBM, the active layer of the organic solar cell, and 400 nm for CIGS active layer. Our best datum showed an efficiency of 11.41% with a short-circuit current density of 11.56 mA/cm2 and a good spectral response at our optimized thicknesses.
Vincent, Premkumar,Kim, Do-Kyung,Kwon, Jin-Hyuk,Bae, Jin-Hyuk,Kim, Hyeok Elsevier 2018 THIN SOLID FILMS - Vol.660 No.-
<P><B>Abstract</B></P> <P>The optical characteristics of nanoparticles will vary according to particle size. With decrease in the size of the nanoparticle (NP), the bandgap of the material increases, thus providing a blue-shift in the refractive index of the material. In this study, we analyzed the effect of different sized zinc oxide (ZnO) nanoparticle optical spacer on the ideal short-circuit current density (J<SUB>sc,ideal</SUB>) of an hybrid photovoltaic cell. ZnO was used as an optical spacer in the solar cell structure to improve the light absorbed in the active layer. Refractive index and extinction coefficient of different sized ZnO nanoparticles were calculated using tight binding model. We implemented these results in two different morphological models: nanoparticle model, and thin-film model. In the nanoparticle model, the ZnO NPs were considered as nanospheres which scatter the incoming light. Comparison of these models helped us to evaluate the improvement in the J<SUB>sc,ideal</SUB> due to scattering effects from nanoparticles. Finally, the optimized structure was obtained for different active layer thicknesses by varying the thickness of the ZnO layer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Refractive index of ZnO nanoparticles is size-dependent. </LI> <LI> Optical spacer's ZnO nanoparticles' size affects the light absorption. </LI> <LI> Two morphological FDTD models, nanoparticle spheres 3D model, and thin-film 1D model. </LI> <LI> The optimized structure was obtained by varying the thickness of the ZnO layer. </LI> </UL> </P>
Vincent, Premkumar,Song, Dong-Seok,Jung, Ji-Hoon,Kwon, Jin-Hyuk,Kwon, Hyeok Bin,Kim, Do-Kyung,Choe, Eunji,Kim, Young-Rae,Kim, Hyeok,Bae, Jin-Hyuk Informa UK (TaylorFrancis) 2017 MOLECULAR CRYSTALS AND LIQUID CRYSTALS - Vol.653 No.1
<P>Optical spacer interlayers are commonly used in solar cells to improve the power conversion efficiency (PCE) of the device. This paper reports a study on the effect of zinc oxide (ZnO) optical spacer interlayer on PCPDTBT:ZnO hybrid solar cell. Optical spacers help to concentrate the spatial distribution of electric field due to light onto the active layer, and thus, improve the light absorption in the active layer. Finite-Difference Time-Domain (FDTD) calculations was carried out on stacked solar cell structure using a simulation software, Lumerical FDTD solutions. Maxwell's equations were solved and the light absorbed by the active layer was computed. The design was optimized with regard to active layer thickness and ZnO optical spacer thickness.</P>
Indoor-type photovoltaics with organic solar cells through optimal design
Vincent, Premkumar,Shin, Sang-Chul,Goo, Ji Soo,You, Young-Jun,Cho, Boram,Lee, Suwoong,Lee, Dong-Wook,Kwon, Se Ra,Chung, Kwun-Bum,Lee, Jae-Joon,Bae, Jin-Hyuk,Shim, Jae Won,Kim, Hyeok Elsevier 2018 Dyes and pigments Vol.159 No.-
<P><B>Abstract</B></P> <P>Indoor solar cells are an attractive option to install in buildings to harvest the energy emitted by indoor lighting. They can be implemented as a stand-alone grid, or as part of an integrated energy harvesting unit. Previous research has utilized amorphous silicon and dye-sensitized solar cells for power generation from a fluorescent light source. In our study, we evaluated the applicability of a poly (3-hexylthiophene):indene-C60 bisadduct solar cell to harvest the light spectrum from an indoor light-emitting diode (LED). Because the absorption peak of poly (3-hexylthiophene) overlaps the LED spectrum peak, it serves as a good candidate for indoor light harvesting under an LED source. We have extracted the power conversion efficiency of the solar cell under different LED illuminance values, such as 200, 800, 1000, and 2000 lx. With the help of finite-difference time domain simulations, we optimized the solar device structure for each illuminance. The results detailed in this article were intended to assess the applicability of organic solar cells as indoor photovoltaics, and to provide a methodology to optimize the photovoltaic structure to maximize its efficiency.</P>
Efficiently-designed hybrid tandem photovoltaic with organic and inorganic single cells
Vincent, Premkumar,Bae, Jin-Hyuk,Kim, Hyeok 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.
<P>Conjugated polymers for solar-cell applications have been extensively studied and have proven highly beneficial in tandem solar-cell structures. This study focuses on achieving power conversion efficiencies of greater than 10% when in tandem with a highly efficient copper indium gallium diselenide (CIGS) solar cell. The optimal design is suggested based on the result of optical simulations on the organic-CIGS tandem structure. This is one of the first reports to show theoretically an organic-CIGS tandem solar cell to obtain an efficiency of greater than 10%. The best PCE was at a thickness of 200 nm for PTB7:PCBM, the active layer of the organic solar cell, and 400 nm for CIGS active layer. Our best datum showed an efficiency of 11.41% with a short-circuit current density of 11.56 mA/cm(2) and a good spectral response at our optimized thicknesses.</P>
Towards maximizing the haze effect of electrodes for high efficiency hybrid tandem solar cell
Vincent, Premkumar,Song, Dong-Seok,Kwon, Hyeok Bin,Kim, Do-Kyung,Jung, Ji-Hoon,Kwon, Jin-Hyuk,Choe, Eunji,Kim, Young-Rae,Kim, Hyeok,Bae, Jin-Hyuk Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.432 No.2
<P><B>Abstract</B></P> <P>In this study, we executed optical simulations to compute the optimum power conversion efficiency (PCE) of a-Si:H/organic photovoltaic (OPV) hybrid tandem solar cell. The maximum ideal short circuit current density (J<SUB>sc,max</SUB>) of the tandem solar cell is initially obtained by optimizing the thickness of the active layer of the OPV subcell for varying thickness of the a-Si:H bottom subcell. To investigate the effect of Haze parameter on the ideal short-circuit current density (J<SUB>sc,ideal</SUB>) of the solar cells, we have varied the haze ratio for the TCO electrode of the a-Si:H subcell in the tandem structure. The haze ratio was obtained for various root mean square (RMS) roughness of the TCO of the front cell. The effect of haze ratio on the J<SUB>sc,ideal</SUB> on the tandem structured solar cell was studied, and the highest J<SUB>sc,ideal</SUB> was obtained at a haze of 55.5% when the thickness of the OPV subcell was 150nm and that of the a-Si:H subcell was 500nm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Current matching is required to maximize efficiency in tandem solar cells. </LI> <LI> Haze effect helps in trapping the light within the active layer. </LI> <LI> Light scattering due to rough electrode surface helped in current matching by balancing light absorption. </LI> <LI> Simulation shows an improvement in ideal short-circuit current density by 7.6% due to haze effect. </LI> <LI> Active layer thickness combination of 500nm (a-Si:H) and 150nm (OPV) exhibited the best optimized structure. </LI> </UL> </P>
김영래,권진혁,Premkumar Vincent,김도경,정현석,한준구,배진혁,박재훈 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.2
The hysteresis of the solution-processed oxide thin-film transistors (TFTs) is fatal issue to interrupt stable operation. So, we came up with uni-directional pre-annealing to solve the problem. There are inevitable defects when solution-processed oxide TFTs are fabricated, due to the porosities by the solvent volatilization. Also oxygen vacancies needed for carrier generation in metal oxide semiconductor can be trap states inducing charge carrier trapping. Uni-directional pre-annealing improved the hysteresis, preventing randomly solvent evaporation and decreased the defects of the film. We can result in advanced stability of the solution-processed oxide TFTs, at the same time showing that the field effect mobility was enhanced from 3.35 cm2/Vs to 4.78 cm2/Vs simultaneously, and exhibiting better subthreshold swing from 0.89 V/dec to 0.23 V/dec.
Shin, Sang-Chul,Vincent, Premkumar,Bae, Jin-Hyuk,Lee, Jae Joon,Nam, Minwoo,Ko, Doo-Hyun,Kim, Hyeok,Shim, Jae Won Elsevier 2019 Dyes and pigments Vol.163 No.-
<P><B>Abstract</B></P> <P>Recently, while increasing research has been focused toward improving the efficiency of various photovoltaic devices under low light intensities, few studies have reported on multi-donor-, multi-acceptor-based bulk heterojunctions (BHJ). In this study, we have demonstrated the utilization of a quaternary BHJ for indoor light energy harvesting applications. We utilized a PCDTBT:PTB7:PC<SUB>61</SUB>BM:PC<SUB>71</SUB>BM-based BHJ structure in order to improve the morphology, absorption window, and the charge transport properties of the photovoltaic device. The ability of ternary photovoltaics to attain high power-conversion efficiency (PCE) by improving the morphology and the charge transport properties had already been validated in another study. We show that the advantages of a stable quaternary solar cell can also be achieved with an optimized BHJ composition ratio of 5:5:3:12, which provides a PCE of 10.6%. Our device showed high shunt resistance and low series resistance, thus facilitating appreciable charge extraction even under low-intensity light conditions such as 500 lx white LED illumination.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Organic photovoltaics (OPVs) have shown to be promising for indoor energy harvesters. </LI> <LI> Complementary absorption of the incident spectrum can improve the short-circuit current density of the OPV. </LI> <LI> Requirement of careful optimization of active layer thickness was observed through optical simulation. </LI> <LI> Experiment verified that quaternary OPV can obtain 10% power-conversion efficiency under indoor LED illumination. </LI> <LI> 10% PCE was attained through complementary absorption and high shunt resistance of the OPV. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>