Synthesis and Characterization of Non-toxic Metal-Organic Halide Photosensitizer for Solar Cell Applications

摘要

This project aims to synthesize and characterize Lead-free Methylammonium and Formamidinium based photosensitizers (dyes). The objectives of this project are to develop and characterize two types of photosensitizer: Methylammonium Titanium-based and Formamidinium Titanium-based dyes. X-ray diffraction and UV-Vis spectrophotometry were used to investigate the crystalline structure of both and determine their optical band gaps, respectively. Both dyes were heated at different temperatures for different heating times to prepare them for testing and characterization. Eight samples of Methylammonium Titanium-based dye were heated at 70, 80, 100, 120, 130 and 140 °C for 10 minutes and for 100 and 120 °C for 20 minutes. Sixteen samples of Formamidinium Titanium-based dye were heated at 80, 100, 120 and 130 °C each for 10, 20, 40 and 60 minutes. It was found out that the treatment temperature and duration have different effects on the crystalline structure and band gap. The best band gap of 2.32 eV value was obtained for Methylammonium Titanium based dye when it was heated at 140 °C for 10 minutes and the best one for Formamidinium Titanium based dye was of a 2.38 eV value obtained when it was heated at 120 °C for 10 minutes. After that, two photovoltaic cells were fabricated using the two dyes and then tested under constant source of voltage (at 0.5 V) and their current response was tested when the light was shining and when it was not. Two types of lights were used, UV (50 microW/cm2 density) and white (60 microW/cm2 density). The results showed that the two dyes are photoactive.