Scientific Program

Day 1 :

  • Energy Harvesting Materials

Session Introduction

Prof. Guan-Jun Yang

Xi'an Jiaotong University

Title: Energy Harvesting Materials
Speaker
Biography:

Abstract:

Hybrid organic-inorganic perovskite solar cells (PSCs), particularly for the planar PSCs, attracted significant attention because of their high efficiency, low fabrication costs, and simple preparation process. However, planar PSCs exhibit lower efficiency and stability than mesoporous PSCs, primarily owing to defects in the electron transport layer (ETL). Here, we introduce a SnO2 nanoparticle modified TiO2 film (SnO2@TiO2) as the ETL. In addition, we propose a simple three-step chemical bath method to achieve such SnO2@TiO2 structure at low temperatures (140°C). The SnO2@TiO2 ETL significantly enhances the electron extraction and decreases the trap states at the perovskite/ETL interface. We achieved average efficiencies  at reverse scan and forward scan of 21.27%, 19.79%, 17.21% and 16.31% for device area of  0.10 cm2, 1.13 cm2, 5.25 cm2 and 10.56 cm2 respectively. Besides, we achieved a certificated efficiency of 15.65% for the normal planar perovskite solar module with masked area of 10.55 cm2. The SnO2@TiO2-based PSCs exhibit enhanced photocurrent and reduced hysteresis. Furthermore, the solar cell retained about 89% of its initial efficiency after about 750 hours of aging in dark and about 93% for 528 hours under full-sun illumination. Because of the low-temperature processability and the absence of spin-coating steps, SnO2@TiO2 ETLs will provide a promising path for the commercialization of PSCs.

  • Nano Materials
Speaker
Biography:

Abstract:

Mixed transition-metal oxides (MTMOs) have been recently receiving increased research interest worldwide due to the striking properties arising from its spinel structure. MTMOs (generally referred to as AxB3-xO4; A, B = Zn, Co, Ni, Fe, etc.) have either stoichiometric or non-stoichiometric compositions. Going a step further from mixed transition metals to mixed transition and post-transition metals, an equimolar multicomponent metal oxide (EMMO) system has been synthesized using reverse co-precipitation (RCP) method for the first time. In this study, the EMMO system was successfully synthesized in a single-phase Fe3O4-type (Fd-3m) structure. The EMMO system with spinel type structure is a combination of 5 different cations (Ni, Mn, Cr, Fe and Al) from transition and post-transition groups, taken using certain criteria that relates Pauling’s ionic radii rule for substitutions in the tetrahedral and octahedral sites.  Heat treatment was optimized to form a single phase nanocrystalline EMMO. X-ray diffraction (XRD) studies revealed the formation of a single phase spinel system. TG (Thermo-gravimetric) analysis revealed that the system was stable throughout the scanning temperature (50 – 1200 oC) and that there was no effect of entropy stabilization. Further characterization studies were carried out using Vibrating Sample Magnetometer (VSM) and Scanning Electron Microscopy (SEM) that revealed the magnetic properties, and microstructure and morphology respectively. The results of these studies are presented and discussed.