Novel dopant-free carrier selective contacts for c-Si solar cell

The overdependence on the tradition energy source have caused a serious of ecologi-cal problems such as the increasing emission of carbon dioxide. To combat this and achieve carbon neutrality, attention has shifted towards sustainable energy, particu-larly wind, tidal, and solar energy. The solar cell catches significant interest due to its ability to directly convert solar energy into electricity through the photovoltaic (PV) effect. The silicon heterojunction (SHJ) cells got a lot of attention with high efficiency and simple fabrication process. The record efficiency of SHJ solar cell is 26.81% from Longi [1]. The fabrication process for SHJ solar cells involves the use of plasma en-hanced chemical vapor deposition (PECVD). However, the use of toxic and flammable gases in the doping process poses safety risks in laboratories. The parasitic absorption introduced by a doped layer, leads to drawbacks in solar cell performance. Conse-quently, alternative materials like dopant-free carrier selective contacts (CSCs), divided into hole transport layers (HTL) and electron transport layers (ETL), have attracted con-siderable interest. Transition metal oxides (TMO) and metal fluorides stand out in do-pant-free material research. This study investigates three metal fluorides (LiF, MgFX, and SrFX) as ETL in SHJ solar cells. Initially, four plasma treatments (PTP, PT, PTB, and noPT) are examined as inter-face treatments in combination with LiF as ETL in SHJ solar cells. Results indicate that PTP is the most compatible with LiF, yielding the highest efficiency. Additionally, stud-ying the impact of LiF thickness on cell performance reveals that a 1 nm thickness shows higher Voc and FF, resulting in higher efficiency. Further exploration into the deposition order of transparent conductive oxide (TCO) and LiF highlights that depos-iting LiF on the rear side preserves passivation properties, ensuring device perfor-mance. Investigations into metal electrode contacts on the rear
Materials Science and Engineering