• Proceedings of the Korean Magnestics Society Conference
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• 2011.12a
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• pp.57-58
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• 2011

We have carried out magnetic and spectroscopic studies on the physical properties of hydrothermally-treated PCBM samples. Strong ferromagnetic ordering was observed depending on the treatment time, and was studied in relation to the atomic bonding configurations.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.157-158
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• 2013

Organic solar cell was fabricated using one-pot deposition of a mixture of NiO nanoparticles, P3HT and PCBM. In the presence of NiO, the photovoltaic performance was slightly increased comparing to that of the device without NiO. When $TiO_2$ thin films with a thickness of 2~3 nm was prepared on NiO nanoparticles using atomic layer deposition, the power conversion efficiency was increased by a factor 2.5 with respect to that with bare NiO. Moreover, breakdown voltage of the film consisting of NiO, P3HT, and PCBM on indium tin oxide was increased by more than 1 V in the presence of $TiO_2$-shell on NiO nanoparticles. It is evidenced that S atoms of P3HT can be oxidized on NiO surfaces, and $TiO_2$-shell on NiO nanoparticles. It is evidenced that S atoms of P3HT can be oxidzed on NiO surfaces, and $TiO_2$ shell heavily reduced oxidation of S at oxide/P3HT interfaces. Oxidized S atoms can most likely act as carrier generation sites and recombination centers within the depletion region, decreasing breakdown voltage and performance of organic solar cells. Our result shows that fabrication of various core-shell nanostruecutres of oxides by atomic layer deposition with controlled film thickness can be of potential importance for fabricating highly efficient organic solar cells.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.71-75
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• 2022

Graphene oxide was stirred with a ZnCl₂:NaCl electrolyte and electrochemically coated by cyclic voltammetry to simplify the electron transpfer layer film forming process for organic solar cells and to fabricate an organic solar cell having it. The device structure is FTO/ZnO:graphene/P3HT:PCBM/PEDOT:PSS/Ag. Morphology and chemical properties of ETL were confirmed by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. As a result of XPS measurement, ZnO metal oxide and carbon bonding were simultaneously confirmed, and ZnO and graphene peaks were confirmed by Raman spectroscopy. The electrical characteristics of the manufactured solar cell were specified with a solar simulator, and the ETL device coated twice at a rate of 0.05 V/s showed the highest photoelectric conversion efficiency of 1.94%.

• International Journal of Advanced Culture Technology
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• v.4 no.1
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• pp.31-36
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• 2016

Morphology evolution of the active layer in bulk hetero-junction organic photovoltaic is modeled and visualized. The width of the phase domain can be predicted using the relationship of characteristics length and evolution time of the process. The 3D numerical simulation of the PCBM/P3HT blend morphology evolution with respect to time is presented. It is observed that the domain width of composition phase can be predicted by using the relationship between value of characteristic length R(t) and evolution time t.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.432-433
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• 2012

Polymer solar cells are fabricated using electrospray (e-spray) deposition process. It shows comparable performance with reference devices, and has different characteristics according to the thickness of the active layer: In the case of the devices with higher fill factor, it shows relatively lower current density, and vice versa. These films are characterized by atomic force microscopy measurement. The results indicate that the comparable power conversion efficiency made by e-spray results from the 'solvent annealing effect' by process conditions and the different thin film property is caused by the degree of self-organization of the polymer.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1068_1069
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• 2009

$TiO_2$의 계면적을 넓힘으로써 태양전지의 특성을 향상시키기 위해 정렬도가 높은 나노 기공 (nanopore, NP) 이산화티타늄 ($TiO_2$)을 이용하여 복합 태양전지를 제작하였다. Polymethyl methacrylate (PMMA)를 사용한 nanoimprinting lithography (NIL) 기술을 이용하여 NP $TiO_2$를 제작하였으며. 광활성층으로는 poly(3-hexylthiophene) (P3HT)와 [6,6]-phenyl $C_{61}$ butyric acid methyl ester (PCBM)을 사용하였다. NP $TiO_2$를 이용한 태양전지의 전력변환효율이 1.49%로 표면이 고른 소자의 효율인 1.18%에 비해 26% 가량 증가하였다. 이와 같은 효율 향상의 원인은 $TiO_2$와 광활성층의 계면이 증가되어 전하의 생성과 분리가 용이해졌기 때문인 것으로 사료된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.192.1-192.1
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• 2014

We report solution-processed organic trilayer solar cells consisting of poly (3-hexylthiophene) (P3HT), a conjugated polyelectrolyte (CPE) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), wherein the effect CPE layer thickness on device properties was investigated. The current-voltage characteristics under illumination and dark as well as photoluminescence were characterized using various concentrations (0.02, 0.1, and 0.3wt%) of to deposit the CPE interlayer between the donor and acceptor layers. We also investigated the influence of molecular dipole moments in the trilayer solar cells by external stimuli. These results provide an experimental approach for investigating the influence of interfacial dipoles on solar cell parameters when placed between the donor and acceptor and allow us to obtaining fundamental information about the donor/acceptor interface in organic solar cells.

• Journal of the Semiconductor & Display Technology
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• v.13 no.2
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• pp.1-5
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• 2014

Transparent and conducting aluminum-doped ZnO electrodes were fabricated by atomic layer deposition methods. The electrode showed the lowest resistivity of $5.73{\times}10^{-4}{\Omega}cm$ at a 2.5% cyclic layer deposition ratio of Trimethyl-aluminum and Diethyl-zinc chemicals. The electrodes showed minimum resistivity when deposited at a temperature of $225^{\circ}C$. The electrode also showed optical transmittance of about 92% at 300 nm. An organic solar cell made with a 300-nm-thick aluminum-doped ZnO electrode exhibited 2.0% power conversion efficiency.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1204-1207
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• 2009

We investigated the device performance of bulk heterojunction solar cells depending on the active layer thickness. For the systematic comparison, the polymer solar cells comprising RR-P3HT:PCBM (1:0.8 (wt%:wt%)) blend films with different thickness were characterized by impedance spectroscopy, and J-V measurement in dark and solar simulated illumination. The device with 120 nm thickness of active layer exhibited maximum power conversion efficiency of 3.5 % under AM 1.5 100mW/$cm^2$ illumination condition.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2321-2324
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• 2013

An improved hybrid solar cell was obtained by focusing on the effects of ligand for CdSe nanoparticles, in the active layers. The performance was compared by mixing nanoparticles capped with pyridine or oleic acid for the acceptor material into poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester based active layer. The solar cells with pyridine capped CdSe nanoparticles showed a power conversion efficiency of 2.96% while oleic acid capped CdSe nanoparticles showed 2.85%, under AM 1.5G illumination. Formation of percolation pathways for carrier transport and a reduction in the hopping event resulted in better performance of pyridine capped nanoparticles.