Silicon solar cells with passivating contacts: Classification and performance

Abstract

The year 2014 marks the point when silicon solar cells surpassed the 25% efficiency mark. Since then, all devices exceeding this mark, both small and large area, with contacts on both sides of the silicon wafer or just at the back, have utilized at least one passivating contact. Here, a passivating contact is defined as a group of layers that simultaneously provide selective conduction of charge carriers and effective passivation of the silicon surface. The widespread success of passivating contacts has prompted increased research into ways in which carrier-selective junctions can be formed, yielding a diverse range of approaches. This paper seeks to classify passivating contact solar cells into three families, according to the material used for chargecarrier selection: doped amorphous silicon, doped polycrystalline silicon, and metal compounds/organic materials. The paper tabulates their current efficiency values, discusses distinctive features, advantages, and limitations, and highlights promising opportunities going forth towards even higher conversion efficiencies.

Rational Approach for High‐Efficiency Dopant‐Free Solar Cells Characterized with Key Parameters

“…Generally, for high‐efficiency c‐Si solar cells, the impact of contact resistivity can be minimized for contact resistivity values of ≤100 mΩ cm 2 . [ 41 ] As shown in Table 1, most DFPC materials have contact resistivity values lower than 100 mΩ cm 2 , so the resistive losses are expected to be minimal. However, FCMs are expected to have very high contact resistivities because they act as insulators.…”

Design considerations for the bottom cell in perovskite/silicon tandems: a terawatt scalability perspective

“…[51][52][53] Materials investigated to achieve passivating contacts include thin oxide/ doped polysilicon, 54 amorphous silicon 55 and various metal oxides. 56,57 Of these, only the combination of a thin silicon oxide coated with a heavily doped polysilicon layer has been intensely studied as a passivating contact for industrial silicon solar cells. 58,59 This passivation approach removes the need for a heavy diffusion in the following way.…”

Extraction of contact resistivity for a partial contact solar cell

“…Partial contacts, which reduce the contact area between the metal and the poorly passivated TMO layer, can improve the passivation compared to full-contact TMO [23][24][25]. In this Figure 1.…”