Silvaco TCAD模拟应用三层氢化纳晶硅薄膜改善IBC-SHJ太阳电池的电学性能并扩大其工艺窗口

Triple-layered nc-Si:H films improve electrical properties and expand process window of IBC-SHJ solar cells simulated by Silvaco TCAD

叉指式背接触硅异质结(IBC-SHJ)太阳电池由于其优异的光学性能备受关注,但是较低的填充因子(FF)限制了其转换效率.本文中,我们用Silvaco TCAD软件模拟了IBC-SHJ太阳电池,发现p-n结和高低结收集载流子的能力有很大差异.高低结内建电场较弱,难以收集电子是FF较低的主要原因.因此,我们用氢化纳晶硅(nc-Si:H)薄膜来代替氢化非晶硅(a-Si:H)薄膜,并且在nc-Si:H薄膜表面覆盖一层超薄高掺杂层进一步提高了载流子传输效率,获得了高达85.3%的FF.此外,三层nc-Si:H薄膜还提高了工艺生产中对掺杂层厚度的容错性,这大大扩展了IBCSHJ太阳电池的工艺窗口.这项工作为解决IBC-SHJ太阳电池的电学问题提供了一条有效的途径,对工艺生产中IBC-SHJ太阳电池的设计具有指导意义.

The scientific studies of silicon-based solar cells such as silicon heterojunction(SHJ)solar cells,tunnel oxide passivated contact(TOPCon)solar cells and interdigitated back contact SHJ(IBCSHJ)solar cells have all made great progress in recent years[1–5].IBC-SHJ solar cells combine IBC and amorphous silicon/crystalline SHJ structures[6,7],achieving a high power conversion efficiency(PCE)of 26.7%with a designated area of 180.4 cm2 in 2017[1].IBC-SHJ solar cells feature a high opencircuit voltage(Voc)owing to the high-quality interface passivation by hydrogenated amorphous silicon(a-Si:H)films[8,9],and a high short-circuit current density(Jsc)owing to the elimination of shadowing effects by IBC designs[10,11].However,the high series resistance(Rs)induces low fill factor(FF)of IBC-SHJ solar cells,which is the main bottleneck for a higher PCE of IBC-SHJ solar cells[12–14].