Room Temperature, Dip Coating Organic Passivation for c-Si surface

• Published in: 2022 IEEE 49th Photovoltaics Specialists Conference (PVSC) p. 0996
• Main Authors: Chen, Kejun, Meyer, Abigail. R, Guthrey, Harvey, Nemeth, William, Theingi, San, Page, Matthew, Agarwal, Sumit, Young, David. L, Stradins, Paul
• Format: Conference Proceeding
• Language: English
• Published: IEEE 05.06.2022
• Subjects: Aluminum oxide; Degradation; Passivation; Silicon nitride; Surface emitting lasers; Surface morphology; Temperature sensors
• DOI: 10.1109/PVSC48317.2022.9938706

Effective surface passivation of crystalline silicon (c-Si) surface by reducing the carrier recombination rate has led to modern c-Si solar cells with efficiencies > 25% in both laboratory and industrial settings. Typical surface passivation techniques include high-temperature silicon oxide (SiOx), amorphous silicon (a-Si:H), hydrogen-rich silicon nitride (SiNx), and aluminum oxide (Al2O3). However, almost all passivation techniques require high-temperature processes that are > 300°C, which poses challenges to certain PV applications that are sensitive to temperature. For example, the above-mentioned passivation methods are not compatible with the degradation study of cells or field modules. Ideally, a room-temperature surface passivation technique that can passivate the edge of a laser-cut cell fragment is necessary for advanced characterization techniques, such as EPR, EDMR, DLTS, local cell J-V and Suns-Voc tests. In this work, we show the passivation results of Nafion polymer on bare nCz and doped n- and p-type poly-Si/SiOxpassivating contact structures We demonstrated that the best Nafion passivated nCz sample has an iVoc of 716 mV, with a J0 of 7 fA/cm2. Compared with Al2O3 passivation, Nafion has slightly lower performance, but it can be extended to wider applications, such as processes sensitive to high temperature. This feature is important, especially when studying the degradation mechanisms of field modules to not destroy the degraded states. Our EPR confirmed that the decrease in Si dangling bond signal is observed after Nafion treatment. We also brought insights into the different morphologies of samples before Nafion.