Modeling of functional materials : perovskite solar cells

• Main Author: Aruj Shukla
• Other Authors: Su Haibin
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials::Energy materials
• Online Access: http://hdl.handle.net/10356/55731
• Institution: Nanyang Technological University

Shortage of conventional energy sources and their negative environmental impact have caused an unprecedented crunch in the energy market in the modern day. Conventional silicon solar cells with high efficiency may have found the solution to this problem but expensive costs and difficulty in manufacturing have stymied the progress. Dye sensitized solar cells (DSSC) which employ TiO2 nanoparticles in complex sandwich structure had been touted as the next alternative, but they are hamstrung by the same issues of commercial viability. Current research suggests that perovskite structures can potentially be a superior replacement to TiO2 due to its superior transport and band gap properties, low toxicity,efficiency and ease of manufacture. These properties, especially the bandgap energy levels and crystallographic structure of perovskite forms the crux of this project and by using state of the art simulation softwares, I have modeled perovskite structures which have yielded some promising results. This report, written as partial fulfillment of the undergraduate thesis shows amongst other results that, the bandgap energy levels are independent of the organic component (A sites in ABX3), concur with experimental data, an increase in the band gap as the symmetry of the crystallographic structure decreases from cubic to tetragonal and most importantly that the band gap of perovskite can be tuned i.e. manipulated, by changing and mixing different compositions of halides in the structure. Such inferences imply that the tunable band gap allows the solar cell to be more sensitive to the incoming spectrum of visible solar radiation as a larger spectrum of radiation can be converted to electric current, which translates to a more efficient and versatile light harvester. However, for a more holistic analysis of perovskite light harvesters as replacement to the existing TiO2 nano particles, a more nuanced modeling and analysis which incorporates a study of transport properties such as trapping effects (for further spike in efficiency), photo catalytic reaction kinetics and surface & bulk defects (for easier fabrication) is demanded as an integral part of future research plans.