■ 제 목 : Eliminating bulk and interface traps for realizing efficient and bright perovskite solar cells
■ 연 사 : 유정완 박사
■ 일 시 : 2021년 9월 15일(수) 오전 11시
■ Zoom: https://zoom.us/j/94327104269?pwd=UDF2WUdpaGZ5RFN2Y2VUeGFsbGpmUT09
■ H o s t : 신병하 교수
■ Abstract :
Lead halide perovskite solar cells are an emerging technology that can be solution processed to yield low-cost, light weight, and flexible photovoltaics. Much of the early work has been focused on developing device structures and processing techniques to improve light absorption and eliminate detrimental traps within the bulk of the perovskite active layer. As a result, the power conversion efficiency (PCE) of perovskite solar cells has improved from ~3% up to ~20% in less than a decade. However, the device efficiency of perovskite solar cells still needs to be much improved in order to compete with traditional photovoltaic technologies, such as Silicon and GaAs, and to ultimately realize the theoretically determined Shockley-Queisser efficiency limit.
I will present our work on further improving the device efficiency by developing a novel interface passivation strategy called selective precursor dissolution (SPD) strategy. The post treatment of the bulk perovskite film with a thin layer of 2-dimentional perovskite via SPD strategy prevented formation of a non-perovskite phase at the interface and resulted in much improved thin film quality with reduced detrimental interface recombinations.
In addition, a high quality electron transport layer (ETL) was developed and a new perovskite composition was adopted to further improve the device performance. A chemical bath deposition (CBD) was used for the synthesis of a tin dioxide (SnO2) ETL. We found the pH of the reaction solution is identified as the key parameter for the CBD of SnO2 that controls the morphology and optoelectronic quality of the SnO2 ETL.
Lastly, to improve the optoelectronic properties of the perovskite active layer, MAPbBr3 is significantly reduced to minimize the band gap penalty, which also resulted in improved effective carrier mobility. MAPbBr3 is commonly added to the perovskite composition to stabilize the