Dr. Teo Siow Hwa

Universiti Malaysia Sabah
Malaysia

Abstract Title: Additive Engineering for Efficient and Stable Perovskite Solar Cells

Biography:

TEO SIOW HWA is a senior lecturer in the Faculty of Science and Technology, Universiti Malaysia Sabah. He received his Ph.D. degree majoring in Catalysis from the Catalysis Science and Technology Research Centre, Universiti Putra Malaysia in 2015. He was then joined as a postdoctoral researcher at the Catalysis Science and Technology Research Centre in 2015–2017. After that, he was appointed as an Assistant Professor at Kyushu Institution of Technology, Japan from 2017 to 2019. His research focuses on catalysis, renewable energy conversion, solar energy materials, perovskite solar cells, and semiconductor photo-physical properties for clean energy applications.

Research Interest:

The performance of high-efficiency inverted perovskite solar cells (PSCs) heavily depends on the quality of the hole transporting layer (HTL) and its interfaces. This study explores how incorporating lanthanum (La) into the NiOx matrix affects defect passivation, ultimately enhancing charge extraction capabilities and stability without sacrificing power conversion efficiency. The introduction of La results in a noticeable improvement in the quality of the La–NiOx layer, eliminating the formation of pinholes. Furthermore, La incorporation modifies the energy band alignment, which enhances hole transport and increases the opencircuit voltage (Voc) beyond 1 V compared to pure NiOx. The advantageous impact of La is further confirmed through photoluminescence measurements, demonstrating effective passivation of trap states. Significantly, PSCs utilizing La–NiOx as the HTL exhibit a 21% increase in efficiency and superior stability compared to those with pristine NiOx. Remarkably, solar cells doped with 3 mole% La maintained 95% of their efficiency after 50 days of storage in a moisture-free desiccator, and 98% efficiency retention was observed for cells stored in a glovebox, substantially outperforming pristine counterparts. The positive effects of La incorporation also extend to the conductivity of the solar cells, evidenced by a reduction in charge transfer resistance (Rct) from 3100 Ω in pristine cells to 1200 Ω. Additionally, the presence of La shortens the carrier lifetime, indicating reduced recombination processes and more efficient charge carrier transfer from the perovskite layer. Overall, while there is still room for enhancing the power conversion efficiency of La–NiOx PSCs through further modifications, the addition of La has demonstrably improved their stability, paving the way for future commercialization opportunities. Keywords: Additive engineering; lanthanum; hole transporting layer; power conversion efficiency; stability