ZnO‐Doped In₂O₃ Front Transparent Contact Enables >24.0% Silicon Heterojunction Solar Cells

Abstract

Transparent conductive oxide (TCO) film acts as the window layer and carrier transport layer of silicon heterojunction (SHJ) solar cells. The optoelectrical and contact properties of TCO films, as well as the sputtering damage, limit the further efficiency improvement. Herein, the microstructure, morphology, and optoelectrical properties of sputtering‐prepared zinc‐doped indium oxide (IZO) are analyzed. The substrate temperature has a significant impact on the film growth and the cell performance. The IZO film is amorphous when substrate temperature is below 200 °C, while it seems the emergence of nanocrystals with the increased temperature, resulting in the highest conductivity (3070 S cm−1) and carrier mobility (47.9 cm2 V−1 s−1). In addition, the low carrier concentration and surface potential of IZO promote less optical parasitic absorption and higher work function. The IZO films are applied as the contact layer of SHJ solar cells. An impressive efficiency of 24.02% on an M2‐sized wafer is achieved, indicating great potential for the mass production application after careful optimization.

Optical, Electrical and Structural Properties of ITO/IZO and IZO/ITO Multilayer Transparent Conductive Oxide Films Deposited via Radiofrequency Magnetron Sputtering

“…These include their heightened stability, superior light transmittance, high conductivity, improved mechanical properties, lower cost, and diminished light reflection. These attributes are vital for enhancing the overall efficiency and performance of solar cells, especially SHJ solar cells [48,49].…”

“…One notable accomplishment emphasized in the study by Qingqing Qiu et al involves optimizing an SHJ solar cell through the incorporation of an intact IZO layer deposition. This optimized cell achieves an impressive efficiency of 24.02%, representing a noteworthy milestone in high-performance solar cell technology [48]. Moreover, the study conducted by Volker Sittinger et al highlights the exceptional qualities of IZO films as opposed to ITO films when employed as top TCO layers in perovskite-silicon tandem solar cells.…”

Vibrational Property-Driven NIR Transparency in X:ZnO (X = Mo, Al) Multilayer Transparent Electrodes for Self-Powered Flexible Optoelectronics

“…Al-doped ZnO (AZO) and Ga-doped ZnO (GZO) films have been realized as successful transparent conducting anodes by sputtering operating in the visible range. Several works reported group-III (B, Al, Ga, In) elements doped in ZnO, and limited reports are available for Mo-doped ZnO (MZO) films; the best results are obtained with the dopants Al and Ga. ,− Mo is projected as the potential dopant in ZnO owing to the lower ionic radius of Mo 6+ compared to Zn 2+ , multiple valence states (+6, 5, 4, 3, 2), and high valence difference with Zn 2+ facilitating more electrons in the system. Recently, Mo-doped transparent oxides were reported to demonstrate IR transparency in contrast to AZO and GZO. − …”

Addressing the stability challenges of TiOx-based passivating contacts for high-efficiency c-Si solar cells

“…This is surprising considering the previously reported fabrication of Si heterojunction cells incorporating a TiO x /TCO contact structure. 23,24 It is well-known that sputtering-induced damage is a common concern for Si-based passivating contacts, including a-Si:H 25,26 and poly-Si. 27 However, thermal treatment aer sputtering TCO layers is oen effective in enabling recovery and improving the passivation quality of these contacts.…”