에너지 변환 응용을 위한 결정질 실리콘 기반 이종접합 소자에 관한 연구
- 에너지 변환 응용을 위한 결정질 실리콘 기반 이종접합 소자에 관한 연구
- Other Titles
- A study on crystalline Si-based heterojunction devices for energy conversion applications
- Alternative Author(s)
- Nam, Yoon Ho
- Issue Date
- Renewable energy has been under a spotlight as a promising solution candidate for the climate change and the environmental pollution. Especially, solar energy has received a great deal of attention because it is the most abundant and the most widely distributed resource than other energy resources such as wind, biofuel, hydropower, etc. In order to generate electricity from the solar light, crystalline silicon (c-Si) solar cells have been widely used
one is the synthesis of multilayer silica nanoparticles (SiO2 NPs) on the Si surface, and the other is the preparation of a periodic Si microhole (MH) structure. We found that light reflection was reduced due to destructive interference at certain wavelengths that depended on the SiO2 NPs layer thickness. In addition, larger diameter SiO2 NPs revealed the worse AR effects due to scattering loss than layers with smaller diameter NPs. For the ARC based on the SiMH structure, light absorption was increased across the whole spectrum because the SiMH array allow second or third chances for light absorption. Compared with the planar cells where the substrate thicknesses are 50, 75, 200m, we analyzed the light absorption spectra about SiMH integrated cells at wavelengths from 400 nm to 1200 nm. We found that the ARC based on the SiMH array was effective for thinner wafers at near infra-red (NIR) region.
however commercially built c-Si solar cells are still expensive and have quite low power conversion efficiency (PCE) compared to the theoretically estimated value of 33% given by the Shockley-Queisser efficiency limit for a single-junction device. Because of this, researchers have focused on various methods for cost reduction and simultaneously on the performance improvement of the final device. In recent years, many researchers extensively studied Si heterojunction solar cells to replace the conventional thermally doped c-Si p-n junction as a platform for cost-effective solar cells with reasonable PCE. In particular, heterojunction solar cells composed of p-type conjugated polymer and n-type Si (n-Si) have become an emerging technology due to the ease of solution processing at low temperature, non-toxicity, and better chemical stability. In this work, we improved the device performance through interfacial engineering between Si and PEDOT:PSS by the interface passivation and the electrical conductivity enhancement at interface. The best performing cell exhibited excellent PCE of 11.95% with remarkably enhanced an open-circuit voltage (Voc) of 614 mV, a short-circuit current density (Jsc) of 26.34 mA/cm2, and a fill-factor (FF) of 73.93%. Furthermore, we have also developed dopant-free Si heterojunction solar cells using transition metal oxides (MoO3, WO3, V2O5, etc.) as a hole-selective contact which were employed in conjunction with the n-Si substrate. We demonstrated a room-temperature processed a MoO3-Si heterojunction solar cell with a Voc of 586 mV, a Jsc of 32.14 mA/cm2, a FF of 78.01%, and a PCE of 14.69%. Besides, we have investigated various antireflection coating (ARC) techniques to boost incident light absorption and eventually the cell efficiency. Especially, we studied two types of the ARC
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- GRADUATE SCHOOL[S](대학원) > FUSION CHEMICAL ENGINEERING(융합화학공학과) > Theses (Ph.D.)
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