Samir Effat, Salah Mohamed, Hajjiah Ali, Shehata Nader, Fathy Marwa, Hamed Aya
Center of Smart Nanotechnology and Photonics (CSNP), SmartCI Research Center, Alexandria University, Alexandria 21544, Egypt.
Department of Electrical Engineering, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt.
Polymers (Basel). 2018 Jun 4;10(6):609. doi: 10.3390/polym10060609.
This paper introduces electrospun nanofibers embedded with ceria nanoparticles as silicon solar cells coaters, showing their influence on the solar cells efficiency. Ceria nanoparticles can be synthesized to have formed oxygen vacancies (O-vacancies), which are associated with converting cerium ions from the Ce state ions to the Ce ones. These O-vacancies follow the rule of improving silicon solar cellconductivity through the hopping mechanism. Besides, under violet excitation, the reduced trivalent cerium Ce ions are directly responsible for down-converting the un-absorbed violet or ultra-violet (UV) wavelengths to a resulted green fluorescence emission at ~520 nm. These are absorbed through the silicon solar cells active layer. When electrospun Poly(vinyl alcohol) (PVA) is embedded with ceria nanoparticles on the rear surface of silicon solar cell, a promising enhancement in the behavior of solar cells current⁻voltage (I⁻V) curve is observed. The efficiency has improved by about 24% of its initial value due to the mutual impact of improving both electrical conductivity and optical conversions from the higher surface-to-volume ratio of electrospun nanofibers embedded by ceria nanoparticles. The solar cell efficiency improvement is due to the mutual impact of both optical down-conversion and better electric paths via the used nanocomposite. The added nanostructures coating can utilize part of the transmitted UV or violet spectrum through the cell as optical conversion from violet to the visible region. In addition, the formed active tri-valent states are associated with O-vacancies which can help in a better conductivity of the generated photoelectrons from the cell through the hopping mechanism. The PVA nanofibers host offers a better distribution of ceria nanoparticles and better conductivity paths for the photoelectrons based on the better surface-to-volume ratio of the nanofibers.
本文介绍了嵌入二氧化铈纳米颗粒的电纺纳米纤维作为硅太阳能电池涂层，展示了它们对太阳能电池效率的影响。二氧化铈纳米颗粒可以被合成形成氧空位（O空位），这与将铈离子从Ce态离子转化为Ce离子有关。这些氧空位通过跳跃机制遵循提高硅太阳能电池导电性的规律。此外，在紫光激发下，还原的三价铈Ce离子直接负责将未吸收的紫光或紫外线（UV）波长下转换为约520nm处产生的绿色荧光发射。这些被硅太阳能电池的有源层吸收。当在硅太阳能电池的背面将电纺聚乙烯醇（PVA）与二氧化铈纳米颗粒嵌入时，观察到太阳能电池电流-电压（I-V）曲线行为有显著增强。由于嵌入二氧化铈纳米颗粒的电纺纳米纤维具有更高的表面积与体积比，提高了电导率和光转换的相互影响，效率提高了约24%。太阳能电池效率的提高归因于光学下转换和通过使用的纳米复合材料形成的更好的电通路的相互影响。添加的纳米结构涂层可以利用透过电池的部分紫外或紫光光谱，实现从紫光到可见光区域的光学转换。此外，形成的活性三价态与氧空位相关，这可以通过跳跃机制帮助电池产生的光电子具有更好的导电性。基于纳米纤维更好的表面积与体积比，PVA纳米纤维主体为二氧化铈纳米颗粒提供了更好的分布，并为光电子提供了更好的导电通路。
