SEMINAR

Halide Perovskite Photovoltaics – Progress and Challenges

Sang Il Seok
Department of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan. Korea

Over the past decade, halide perovskite photovoltaic solar cells (PSCs) have attracted intensive interest, with power conversion efficiencies (PCEs) now approaching 26%. The rapid improvement in PCE of PSCs was achieved mainly by optimizing the device architecture, the uniform thin film deposition process, and the material composition of the halide perovskite. Our research team, who led the birth and development of efficient PSCs, proposed for the first time a bi-layer structure composed of a nano-structured photoelectrode and a perovskite thin film. In addition, the introduction of a medium that retards the rapid crystallization between organic cations and PbI2 through solvent engineering or intramolecular exchange processes has made a significant contribution to the development of technology for uniform perovskite thin film deposition. At the same time, we manipulated the chemical composition of the perovskite materials to stabilize -phase of formamidinium lead iodide (FAPbI3) for fabricating efficient PSCs. The efficiency is further improved by reducing the grain boundary and surface defect concentration of FAPbI3. However, these achievements have only been obtained in small laboratory scale devices using lead-based halide perovskites, and their performance is significantly lower when processing on larger industry-relevant substrate sizes. Moreover, the material may deteriorate when exposed in open air, and panels containing lead may leach and contaminate the environment. These challenges, along with the many successes of perovskite solar cells, are the driving force behind significant efforts in various fields to achieve high performance in a large area and find stable and lead-free alternatives. In today’s presentation, I would like to introduce the birth, evolution, and challenge of halide perovskite photovoltaics.