Excess Carrier Lifetime Improvement in c-Si Solar Cells by YAG:Ce^(3+)-Yb^(3+)

Ce3＋-Yb3＋ doped Y3Al5O12 （YAG） is a luminescent down-conversion material which could convert visible pho- tons to near infrared photons. In this work, YAG：Ce3＋-Yb3＋ is applied on the front surface of mass-produced mono crystalline Si solar cells. For the coated cells, the external quantum efficiencv from the visible to the near infrared is improved, and the energy conversion efficiency enhances from 11.70% to 12.2% under AMI.SG. Furthermore, the phosphor down-conversion effect on the solar cell is characterized by the microwave detected photoconductivity technique on the n-type silicon wafer under the 977nm excitation. The down-conversion materials improve the average excess carrier lifetime from 22.5μs to 24.2#s and the average surface recombi- nation velocity reduces from 424.Scm/s to 371.6cm/s, which reveal the significant reduction in excess carrier recombination by the phosphors.

麦哲伦海山群富钴结壳铈富集的控制因素

利用ICP-OES和ICP-MS,分析了麦哲伦海山群西北端MK海山2170 m水深的MKD23B-3号富钴结壳样品,获得了其剖面上Ce,Co和P2O5含量数据。结果显示,该样品未磷酸盐化壳层的过剩Ce(Cexs)与Co含量之间呈明显的正相关关系,相关系数R2高达0.7893;与生长速率呈负相关关系,相关系数R2高达0.7211,表明壳层生长速率是制约结壳Ce含量的主因,高的Ce含量是低的生长速率造成的。在假设海水pH,Mn2+等条件不变的前提下,结壳生长速率正相关于Fe,Mn的沉积通量,而Fe,Mn的沉积通量正相关于海水中溶解氧含量。因此,在海水pH,Mn2+等条件不变的前提下,Cexs负相关于海水中溶解氧含量,海水溶解氧含量只是制约结壳Ce含量的间接因素,纠正了"结壳高Ce异常指示其形成时海水中高溶解氧含量"的认识。