Silicon (Si)‐based dopant‐free heterojunction solar cells (SCs) featuring carrier‐selective contacts (CSCs) have attracted considerable interest due to the extreme simplifications in their device structure and manufacturing procedure. However, these SCs are limited by the unsatisfactory contact properties on both sides of the junction, and their efficiencies are not comparable with those of commercially available Si SCs. In this report, a high‐performance silicon‐oxide/magnesium (SiO_x/Mg) electron‐selective contact (ESC) design is described. Combining an ultrathin SiO_x and a low work function Mg layer, the novel ESC simultaneously yields low recombinative and resistive losses. In addition, deposition of Mg on SiO_x relaxes the restriction on the threshold thickness of the SiO_x for electron tunneling and therefore broadens the optimization space for rear‐sided passivation. Meanwhile, hole‐selective contact with boosted light harvesting and suppressed interfacial recombination is achieved by forming a fully conformal contact between the conducting poly(3,4‐ethylene dioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) and periodic Si pyramid arrays. With the double‐sided carrier‐selective contact designs, PEDOT: PSS/Si/SiO_x/Mg SCs with efficiency of 15% are finally obtained via a totally dopant‐free processing. Subsequent calculations further indicate a pathway for the improvement of these contacts toward an efficiency that is competitive with conventionally diffused pn junction SCs.

中文翻译：

---

基于氧化硅/镁的双功能电子选择性触点：在保持表面钝化的同时调整异质界面带结构

由于其器件结构和制造工艺的极大简化，具有载流子选择触点（CSC）的基于硅（Si）的无掺杂异质结太阳能电池（SC）引起了人们的极大兴趣。但是，这些SC受限于结两侧的接触特性，因此其效率无法与市售Si SC媲美。在本报告中，描述了一种高性能的氧化硅/镁（SiO _x / Mg）电子选择触点（ESC）设计。新型ESC结合了超薄SiO _x和低功函数Mg层，同时产生了较低的复合损耗和电阻损耗。此外，Mg在SiO _x上的沉积放宽了对电子隧穿SiO _x阈值厚度的限制，因此拓宽了背面钝化的优化空间。同时，通过在导电聚（3,4-乙撑二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT：PSS）与周期性Si金字塔阵列之间形成完全共形的接触，可以实现具有增强的光收集和抑制的界面重组的空穴选择性接触。通过双面载流子选择接触设计，最终通过完全无掺杂的工艺获得了效率为15％的PEDOT：PSS / Si / SiO _x / Mg SC。随后的计算进一步表明了改善这些接触的途径，以达到与传统扩散的pn结SC竞争的效率。