材料期刊网

虽然介质包覆的金属纳米颗粒已经在试验中频繁应用到太阳能电池中,通过减少金属表面激子的猝灭和电荷的复合来提高电池性能.但是基本没有理论研究工作去解释金属颗粒的介质包覆层是如何影响器件的光学性能.本文从理论计算角度研究了二氧化硅包覆银纳米球掺杂在有机太阳能电池活性层中对活性层的光捕获的影响.研究结果表明在垂直入射的条件下,在350 nm到850 nm的波段内,加入包覆Ag纳米球的最优器件的活性层对标准太阳光谱(AM 1.5)积分后的光吸收率达到81.5％.与等效的平板结构相比,活性层的光吸收增强了9.54％.具体的场分布的分析得到光吸收增强原因主要是偶极共振、表面等离激元激发以及之间的相互耦合作用所致.经过对结构参数的研究,发现了介质包覆层越薄,增强效果越明显;包覆的介质层的折射率对光吸收性能的影响不是很明显.

Although dielectric-coated metallic nanoparticles were frequently applied in organic solar cells (OSCs) for improving the device performance by preventing the possible exciton quenching and charge recombination at the metal surface,there have been few theoretical researches addressing how the dielectric-coating of metal nanoparticles influences the optical performance of OSCs.The effect of coating silver nanaspheres were theoretically studied by a silica film on the absorption performance of OSCs.This results show that an integrated light absorption efficiency of 81.5％ in the PSBTBT:PC71 BM active layer over the wavelength range from 350 nm to 850 nm at normal incidence,outperforming the structurally identical planar control cell by 9.54％.Detailed investigations reveal that the excitation of the dipole localized surface plasmon resonance,SPP and LSP and their mutual coupling are responsible for the observed broadband enhancement in light absorption.Through studying the influences of structure parameters,the results show that the thinner dielectric coating is more favorable for light absorption enhancement.In addition,refractive index impact on absorption enhancement of OSC is not obvious.