• Applied Science and Convergence Technology
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• 제26권4호
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• pp.91-94
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• 2017

AThe effect of localized surface plasmon on silicon substrates was studied using silver nanoparticles. The nanoparticles were formed by self-arrangement through the surface energy using rapid thermal annealing (RTA) technique after the thin nanolayer of silver was deposited by thermal evaporation. By the theoretical calculation based on Mie scattering and dielectric function of air, indium tin oxide (ITO), and silver, the strong peak of scattering cross section of silver nanoparticles was found at 358 nm for air, and 460 nm for ITO, respectively. Accordingly, the strong suppression of reflectance under the condition of induced light of $30^{\circ}$ occurred at the specific wavelength which is almost in accordance with peak of scattering cross section. When the external quantum efficiency was measured using silicon solar cells with silver nanoparticles, there was small enhancement peak near the 460 nm wavelength in which the light was resonated between silver nanoparticles and ITO.

• 한국전기전자재료학회논문지
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• 제30권3호
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• pp.192-197
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• 2017

Hydrogenated Amorphous Silicon (a-Si:H) is used as an emitter layer in HIT (heterojunction with Intrinsic Thin layer) solar cells. Its low band gap and low optical properties (low transmittance and high absorption) cause parasitic absorption on the front side of a solar cell that significantly reduces the solar cell blue response. To overcome this, research on CSC (carrier Selective Contacts) is being actively carried out to reduce carrier recombination and improve carrier transportation as a means to approach the theoretical efficiency of silicon solar cells. Among CSC materials, molybdenum oxide ($MoO_x$) is most commonly used for the hole transport layer (HTL) of a solar cell due to its high work function and wide band gap. This paper analyzes the electrical and optical properties of $MoO_x$ thin films for use in the HTL of HIT solar cells. The optical properties of $MoO_x$ show better performance than a-Si:H and ${\mu}c-SiO_x:H$.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.282-286
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• 2011

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. We performed rigorous ray tracing simulation of the flat Fresnel lens and light-pipe. The light-pipe can play imporatant roles of redistributing solar energy at the solar cell and increase the mechanical tolerance so that it can increase the lifetime of the high-concentration solar PV system and decrease the cost of manufacturing. To investigate the sensitivity of the solar power generated by the concentrated solar PV according to the performance of lens and light pipe, we performed raytracing and executed a simulation of electrical performance of the solar cell when it is exposed to the non-uniform illumination. We could conclude that we can generate 95 % or more energy compared with the energy that can be generated by perfectly uniform illumination once the total energy is given the same.

• Current Photovoltaic Research
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• 제4권3호
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• pp.114-118
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• 2016

$Cu_{1.8}Zn_{1.2}(Sn_{1-x}Ge_x)S_4$ (CZTGeS) nanocrystals were mechanochemically synthesized from elemental precursor powders without using any organic solvents and any additives. The composition of CZTGeS nanocrystals were systematically varied with different Ge mole fraction (x) from 0.1 to 0.9. The XRD, Raman spectroscopy, high-resolution TEM, and diffuse reflectance studies show that the as-synthesized CZTGeS nanocrystals exhibited consistent changes in various structural and optical properties as a function of x, such as lattice parameters, wave numbers for $A_1$ Raman vibration mode, interplanar distances (d-spacing), and optical bandgap energies. The bandgap energy of the synthesized CZTGeS nanocrystals gradually increases from 1.40 to 1.61 eV with increasing x from 0.1 to 0.9, demonstrating that Ge-doping is useful means to tune the bandgap of mechanochemically synthesized nanocrystals-based kesterite thin-film solar cells. The preliminary solar cell performance is presented with an efficiency of 3.66%.

• 한국수소및신에너지학회논문집
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• 제33권1호
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• pp.113-120
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• 2022

Quantum dots (QDs) are attractive photosensitizer candidates for application not only in solar cells but also in solar hydrogen generation. For the prepartion of highly efficient QD-sensitized photoelectrodes, it is important to reduce electron recombination at the photoanode/electrolyte interface. Here, we study on the coating condition of ZnS passivation layers on the photoanodes in QD-sensitized solar cells (QDSCs). The ZnS passivation layers are coated by successive ionic layer adsorption and reaction method, and as the cation precursor, zinc acetate and zinc nitrate are empolyed. Due to the higher pH of cation precursor solution, the ZnS loading is improved when the zinc acetate is used, compared to the zinc nitrate. This improved loading of ZnS leads to the reduced electron recombination at the surface of photoanodes and the enhaced conversion efficiency of QDSCs from 6.07% to 7.45%.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.376-376
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• 2011

I-III-VI2 chalcopyrite compounds, particularly copper, indium, gallium selenide(Cu(InxGa1-x)Se2, CIGS), are effective light-absorbing materials in thin-film solar application. They are direct band-gap semiconductors with correspondingly high optical absorption coefficients. Also they are stable under long-term excitation. CIS (CIGS) solar cell reached conversion efficiencies as high as 19.5%. Several methods to prepare CIS (CIGS) absorber films have been reported, such as co-evaporation, sputtering, selenization, and electrodeposition. Until now, co-evaporation is the most successful technique for the preparation of CIS (CIGS) in terms of solar efficiency, but it seems difficult to scale up. CIS solar cells have been hindered by high costs associated with a fabrication process. Therefore, inorganic colloidal ink suitable for a scalable coating process could be a key step in the development of low-cost solar cells. Here, we will present the preparation of CIS photo absorption layer by a solution process using novel metal precursors. Chalcopyrite copper indium diselenide (CuInSe2) nanocrystals ranging from 5 to 20nm in diameter were synthesized by arrested precipitation in solution. For the fabrication of CIS photo absorption layer, the CuInSe2 colloidal ink was prepared by dispersing in organic solvent and used to drop-casting on molybdenum substrate. We have characterized the nanoparticless and CIS layer by XRD, SEM, TEM, and ICP.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.454-454
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• 2010

In order to achieve a high efficient a-Si solar cell, the TCO (transparent conductive oxide) substrates are required to be a low sheet resistivity, a high transparency, and a textured surface with light trapping effect. Recently, a zinc oxide (ZnO) thin film attracts our attention as new coating material having a good transparent and conductive for TCO of solar cells. In this paper the optical properties of $H_2$ post-treated BZO (boron doped ZnO, ZnO:B) thin film are investigated with $O_2$-plasma treatment. The BZO thin films by MOCVD (Metal Organic Chemical Vapor Deposition) are investigated and the samples of $H_2$ post-treated BZO thin film are tested with $O_2$-plasma treatment by plasma treatment system with 13.56 MHz as RIE (Reactive Ion Etching) type. We measured the optical properties and surface morphology of BZO thin film with and without $O_2$-plasma treatment. The optical properties such as transmittance, reflectance and haze are measured with integrating sphere and ellipsometer. This result of the BZO thin film with and without $O_2$-plasma treatment is application to the TCO for solar cells.

• Journal of Electrochemical Science and Technology
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• 제4권4호
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• pp.125-139
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• 2013

The electrical conductive polymers (ECPs) reported at my research group are introduced in this review, which works are started from the late Professor Su-Moon Park's pioneering research for polyaniline at the University of New Mexico. The electrochemical and spectroelectrochemical properties and their applications to sensor and energy conversion systems are briefly described. At first, the growth and degradation mechanism of polyaniline describes and we extend to polypyrrole, polyazulene, polydiaminonaphthalenes, and polyterthiophene derivatives. In addition, the preparation of monomer precursors having functional groups is briefly described that can give us many exceptional applications for several chemical reactions. We describe the application of these ECPs for the fabrication of chemical sensors, biosensors, biofuel cells, and solar cells.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.274-274
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• 2006

Recently, conjugated polymer solar cells have attracted a great deal of attention. In this work, we applied the various scanning probe techniques to characterize composite materials typically used to fabricate polymer solar cells: poly-3(hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and P3HT/PCBM/Au nanoparticle (NP) samples. The latter is studied due to the idea of using the gold NP surface plasmon to enhance the optical absorption of the composite films. AFM is used to characterize the film morphology whereas conducting AFM is used to study the charge transport properties at the nanoscale. We found that there is a direct correlation between the nanoscale charge transport measurements and the device efficiencies.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.349-349
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• 2009

High quality ZnO:Al films were prepared on glass substrates by in-line RF magnetron sputtering and their surface morphologies were modified by wet-etching process in dilute acid solution to improve optical properties for application to silicon thin film solar cells as front electrode. The as-deposited films show a strong preferred orientation in [001] direction under our experimental conditions. A low resistivity below $5{\times}10^{-4}{\Omega}{\cdot}cm$ and high optical transmittance above 80% in a visible range are achieved in the films deposited at optimized conditions. After wet-etching, the surface morphologies of the films are changed dramatically depending on the deposition conditions, especially working pressure. The optical properties such as total/diffuse transmittance, haze and angular resolved distribution of light are varied significantly with the surface morphology feature, whereas the electrical properties are seldom changed. The cell performances of silicon thin film solar cells fabricated on the textured films are also evaluated in detail with comparison of commercial $SnO_2$:F films.