Spray deposited TiO₂thin films for large-area TiO₂/p-Si heterojunction solar cells

Abstract

Carrier selective contacts (CSC) have the potential to lower the cost of photovoltaic (PV) cells. In the present work p-Si/TiO2 heterojunction solar cells have been fabricated using titanium dioxide (TiO2) as an electron-selective layer. Thin uniform anatase TiO2 films have been deposited using a commercially viable spray deposition technique over large area Si substrates. With a simple architecture of Al (200 nm fingers)/Al (15 nm thin film)/TiO2/c-Si(p)/Ag (200 nm), a highest conversion efficiency of 1.56 % has been achieved for the TiO2 carrier selective contact based solar cell with an active area of ~3.84 cm2. The minority carrier lifetime value of the TiO2 coated Si wafer was found to be less than that of the uncoated wafer, indicating the inability of the anatase TiO2 layer to provide surface passivation. Suns-VOC measurements yielded comparable values of the implied open circuit voltage for both the uncoated and the TiO2 coated Si wafers. Spray deposition technique can be used for scalable fabrication of carrier selective contact based heterojunction solar cells.

Solution‐Processed PEDOT:PSS/p‐Si/ZnO Heterojunction Solar Cells

“…To yield a proper energy band matching, n‐type semiconductor materials such as ZnO, [ 13 ] TiO 2 , [ 14 ] SnO 2 , [ 15 ] PCBM are usually used in p‐Si heterojunction solar cells to form a built‐in field. [ 16 ] Among them, ZnO has high electron mobility (115–155 cm 2 V −1 s −1 ), [ 17 ] very high transmittance in the visible spectrum, suitable energy level, and low‐temperature processing capability, and more importantly, low cost, which result in ZnO becoming an excellent electron transport material in Si solar cells.…”