Presentation Information
[9p-P06-25]Gradient Sn Surface Doping and Shallow Defect Passivation via Chemical Bath–Deposited SnO2 on TiO2 Bilayer for Enhanced Carrier Extraction in Perovskite Solar Cells
〇(P)ShihHsuan Chen1, WeiHao Chiu Chiu1, YingKai Huang1, MingChung Wu1, Kun-Mu Lee1 (1.Chang Gung Univ.)
Keywords:
Perovskite solar cells,Defect Passivation,Carrier Extraction
Perovskite solar cells (PSCs) have recently surpassed 27% power conversion efficiency (PCE), demonstrating great potential as next-generation photovoltaics. In n-i-p architectures, the electron transport layer (ETL) is vital for charge extraction and recombination suppression. While mesoporous TiO2(m-TiO2) is widely adopted due to its stability, the high-temperature sintering (400–500 °C) required induces surface defects (e.g., Ti3+), serving as non-radiative recombination centers. Although element doping can partly passivate these, it is often inadequate. SnO2, with high electron mobility and favorable band alignment, is a promising alternative. We developed a novel SnO2/m-TiO2 bilayer ETL via low-temperature chemical bath deposition (CBD), enabling uniform SnO2 coating on TiO2. This structure forms stepwise energy alignment to facilitate electron extraction and suppress interfacial recombination. Notably, during CBD, Sn4+ diffuses into TiO2, forming graded doping that enhances electron transport and band alignment. This bilayer boosts the open-circuit voltage from 1.048 V to 1.113 V and achieves a peak PCE of ~24%. Moreover, by integrating CBD with screen printing, we fabricated uniform large-area (100 cm2) ETLs, delivering consistent PCEs from 21.75% to 23.52%, confirming the reproducibility and scalability of this approach.