Regulating crystallization dynamics and crystal orientation of methylammonium tin iodide enables high-efficiency lead-free perovskite solar cells

Tin (Sn)-based perovskite solar cells (PSCs) have attracted much attention because they are more environmentally friendly than lead-based PSCs. However, the fast crystallization of Sn-based perovskite film and the easy...

Recent Advances in Tin-based Hybrid Organic-Inorganic PSCs: Additives for Improved Stability and Performance

Perovskite solar cells (PSCs) materials are progressing as potential candidates for the future generation of photovoltaics. Despite the most efficient photovoltaic performance, lead-based perovskite materials are not considered for commercialization due to the high toxicity of lead. One of the promising alternatives is tin (Sn)-based perovskites, which exhibits equivalent ionic size as lead and outstanding absorption properties. However, Sn-based perovskite materials have stability and low-performance issues because of the easy oxidation of Sn2+ to Sn4+and fast crystallization. This paper gives a focused overview of the notable recent studies to address the stability and low-performance challenges of Sn-based hybrid organic-inorganic perovskite (Sn-HOIP) materials for solar cells by using functional additives. To date, the addition of SnF2 additive in the methylammonium tin iodide-based PSCs has shown the highest efficiency of 7.78% and maintains 70% of original efficiency over 200-hours. In the case of formamidinium tin iodide-based PSCs, the addition of phenylhydrazine hydrochloride significantly increases the power conversion efficiency to 11.40% from 5.60% for a pristine device. However, further improvement in the stability and efficiency of Sn-based PSCs requires a molecular-level understanding of the role of existing and new candidates of additives tailored for evolving Sn-HOIP materials.

Numerical Study of Transparent Conductive Oxide (TCO) Layer on the Performance of Methyl-Ammonium Tin Iodide (CH3NH3SnI3) Perovskite Solar Cells Using SCAPS

Substrates used in perovskite solar cells as front contact are usually transparent conductive oxide (TCO) to allow light to pass through the device. The dominating TCO employed in perovskite solar cells are indium-doped tin oxide (ITO) and fluorine-doped tin oxide (FTO). However, it is imperative to investigate alternative TCOs due to the scarcity of indium metal, relatively low electrical conductivity and high leakage current in ITO and FTO. In this study, simulation has been carried out using Solar Capacitance Simulator (SCAPS) to investigate the efficiency of methyl-ammonium tin iodide (CH3NH3SnI3) based solar cells including various TCOs such as boron-doped zinc oxide (BZO), molybdenum trioxide (MoO3) and zinc oxide (ZnO). TCO parameters such as thickness, donor concentration and operating temperature were varied to study their influence on device performance. The best device performance was achieved using MoO3 with power conversion efficiency of 25.83 % and Jsc, Voc and FF of 32.44 mA/cm2, 0.979 V and 81.38 % respectively. The work shows the potential of fabricating an improved CH3NH3SnI3 perovskite solar cell with MoO3 as front contact.