Novel hole transporting materials for methylammonium lead halide (CH3NH3)PbI3 perovskite sensitized mesoscopic solar cells

Abstract

Hole Transporting Materials (HTMs) are of significant importance towards a perovskite solar cell device. Their vital role can be appreciated by understanding the fundamentals of perovskite solar cells, and the various imperative characteristics that were desired of them were hypothesised. In this report, photovoltaic devices were introduced and the literature review is then focused on the role of the HTMs inside these devices, and the considerations leading to the synthesis of the two new, novel HTMs. Herein, I have reported the design and synthesis two HTMs, one with furan as central core (F101) and other HTM with Organo-Silicon core. The molecular structure of each HTM was identified by MALDI-TOF mass spectroscopy, 1H Nuclear Magnetic Resonance (NMR) spectroscopy. Differential Scanning Calorimetry (DSC) was used to investigate the glass-transition temperature (Tg), which revealed high thermal stability for both HTMs. Electrochemical and optical investigations were made by employing cyclic voltammetry (CV) and UV–Vis absorption spectroscopy, respectively. All results yielded evinced that both F101 and Si101 have favourable optical absorption properties occurring at suitable energy levels, thus, are suitable for application inside a perovskite solar cell device. Several devices were fabricated using standard procedures together with the as-synthesized HTMs and Spiro-OMeTAD, a widely reported and HTM with superior performances. Devices with Spiro-OMeTAD showed a Power Conversion Efficiency (PCE) of 13.25%, while the devices fabricated using the as-synthesized HTMs of F101 and Si101 showed a comparable PCE of 13.12% and 11.00% respectively. These could be interpreted as encouraging results and potentially improves the possibility of designing small molecule hole conductors for application inside of mesoscopic photovoltaic devices; acting as good alternatives towards even the best of performing HTMs currently existing in the commercial market.