• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.43.2-43.2
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• 2011

Minority Carrier recombination should be suppressed for high efficiency solar cells. However, impurities in the silicon bulk region deteriorate the minority carrier lifetimes, causes conversion efficiency drop. In this study, we introduced phosphorus external gettering for silicon heterojunction solar cell substrates. Gettering was undergone at 750, 800, 850 and $900^{\circ}C$ in furnace for 30 minutes. Bulk lifetimes and calculated diffusion length were improved. We applied phosphorus gettering to silicon heterojunction solar cells. Gettered group and ungettered group were used as substrate of silicon heterojunction solar cells. After fabrication, characteristics of solar cells were analyzed. The results were observed to see the enhancement of substrate quality which directly connects with solar cell properties.

• Current Photovoltaic Research
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• 제4권2호
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• pp.48-53
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• 2016

We report the effect of physical load on the stability of organic solar cells under physical loads. The active layers in organic solar cells were fabricated with bulk heterojunction films (BHJ) films of poly (3-hexylthiophene) and phenyl-$C_{61}$-butyric methyl ester. The loading time was varied up to 60 s by keeping the physical load constant. Results showed that the open circuit voltage was not influenced by the physical load but other solar cell parameters were sensitive to the loading time. The fill factor was very slightly increased at 15 s, while short circuit current density was well kept for 30 s. The power conversion efficiency was reasonably maintained for 45 s but became significantly decreased by the continuous loading for 60 s.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.88-93
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• 2008

지역규칙성 폴리3핵실티오펜과 용해성 플러렌 블렌드로 이루어진 벌크이종접합 고분자 태양전지를 제작하였다. 고분자 블렌드 필름에 대한 열처리 효과가 필름의 결정 구조와 자외선/가시광선 흡수스펙트럼에 주는 영향을 조사하였다. 그 후, 열처리에 의한 필름의 결정구조와 태양전지 효율의 상관관계를 연구하였다. 그 결과, $150^{\circ}C$에서 열처리한 필름이 분자간 상호작용 및 결정성측면에서 최적이었으며, 이 때, 고분자 태양전지의 에너지 전환 효율은 3.2 %이었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.59.2-59.2
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• 2012

Polymer solar cells utilize bulk heterojunction (BHJ) type photo-active layer in which the electron donating polymer and electron accepting $C_{60}$ derivatives are blended. We found there is significant charge recombination at the interface between the BHJ active layer and electrode. The charge recombination at the interface was effectively reduced by inserting wide band gap inorganic interfacial layer, which resulted in efficiency and stability enhancement of BHJ polymer solar cell.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.661-664
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• 2013

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2148-2154
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• 2013

Three push-pull organic semiconductors, TPA-$Th_3$-MMN (1), TPA-ThTT-MMN (2), and TPA-ThDTT-MMN (3), comprising a triphenylamine donor and a methylene malononitrile acceptor linked by various ${\pi}$-conjugated thiophene units were synthesized, and the effects of the ${\pi}$-conjugated bridging unit on the photovoltaic characteristics of solution-processed small-molecule organic solar cells based on these semiconductors were investigated. Planar bridging units with extended ${\pi}$-conjugation effectively facilitated intermolecular ${\pi}-{\pi}$ packing interactions in the solid state, resulting in enhanced $J_{sc}$ values of the SMOSCs fabricated with bulk heterojunction films.

• Transactions on Electrical and Electronic Materials
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• 제13권2호
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• pp.98-101
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• 2012

I studied the stability of organic photovoltaic cells in terms of P3HT:PCBM-71 blend ratio as a function of storage time. I obtained the best cell performance by optimizing the blend ratio of electron donor and electron acceptor within the active layer. In this study, I found that the more the P3HT:PCBM ratio increases within the active layer, the more the cell efficiency decreases as the storage time increases. As a result, the best optimized blend ratio was the 1:0.6 ratio of P3HT:PCBM-71, and cell efficiency of the device with the 1:0.6 blend ratio was 4.49%. The device with the best cell efficiency showed good stability.

• Transactions on Electrical and Electronic Materials
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• 제10권3호
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• pp.75-79
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• 2009

An intrinsic silicon thin film passivation layer is deposited by the microwave remote-plasma enhanced chemical vapor deposition at temperature of $175^{\circ}C$ and various gas ratios for solar cell applications. The good quality amorphous silicon films were formed at silane $(SiH_4)$ gas flow rates above 15 seem. The highest effective carrier lifetime was obtained at the $SiH_4$, flow rate of 20 seem and the value was about 3 times higher compared with the bulk lifetime of 5.6 ${\mu}s$ at a fixed injection level of ${\Delta}n\;=\;5{\times}10^{14}\;cm^{-3}$. An annealing treatment was performed and the carrier life times were increased approximately 5 times compared with the bulk lifetime. The optimal annealing temperature and time were obtained at 250 $^{\circ}C$ and 60 sec respectively. This indicates that the combination of the deposition of an amorphous thin film at a low temperature and the annealing treatment contributes to the excellent surface and bulk passivation.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.559-565
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• 2011

The following noble series of statistical copolymers, poly[(2-(3-thienyl)ethanol n-butoxycarbonylmethylurethane)-co-3-hexylthiophene] (PURET-co-P3HT), were synthesized by the chemical dehydrogenation method using anhydrous $FeCl_3$. The structure and electro-optical properties of these copolymers were characterized using $^1H$-NMR, UV-visible spectroscopy, elemental analysis, GPC, DSC, TGA, photoluminescence (PL), and cyclic voltammetry (CV). The statistical copolymers, PURET-co-P3HT (1:0, 2:1, 1:1, 1:2, 1:3), were soluble in common organic solvents and easily spin coated onto indium-tin oxide (ITO) coated glass substrates. Hybrid bulk heterojunction photovoltaic cells with an ITO/G-PEDOT/PURET-co-P3HT:PCBM:Ag nanowires/$TiO_x$/Al configuration were fabricated, and the photovoltaic cells using PURET-co-P3HT (1:2) showed the best photovoltaic performance compared with those using PURET-co-P3HT (1:0, 2:1, 1:1, 1:3). The optimal hybrid bulk heterojunction photovoltaic cell exhibits a power conversion efficiency (PCE) of 1.58% ($V_{oc}$ = 0.82 V, $J_{sc}$ = 5.58, FF = 0.35) with PURET-co-P3HT (1:2) measured by using an AM 1.5 G irradiation (100 mW/$cm^2$) on an Oriel Xenon solar simulator (Oriel 300 W).

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.246-249
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• 2007

현재까지 $P3HT:C_{60}-PCBM$계는 고분자 유기 태양전지에서 가장 좋은 효율을 보여주고 있다. 그러나 보다 고효율의 소자 제작을 위해 신재료에 대한 연구들이 활발히 진행되고 있으며, 본 연구에서는 $C_{60}-PCBM$ 대신 $C_{70}-PCBM$을 합성하여 소자를 제작하였다. $C_{70}-PCBM$은 $C_{60}-PCBM$에 비하여 가시광선 영역에서 상대적으로 높은 광흡수율을 보여 주었으며, 이것은 광전류의 향상을 가져왔다. 소자제작의 주요 변수로 $P3HT:C_{70}-PCBM$ 광활성층의 처리 조건, 즉, 용매, 조성비, 열처리 조건, 광활성층의 두께 등을 조절하였는데, buffer층(LiF 층) 등이 도입되지 않은 간단한 제작조건 하에서도 본 $C_{70}-PCBM$는 $C_{60}-PCBM$계에 버금가는 3.5% (AM 1.5G, 100 $mW/cm^{2}$ 조건) 이상의 효율을 나타내었다.