Carrier lifetimes of >1 μs in Sn-Pb perovskites enable efficient all-perovskite tandem solar cells

Abstract

All-perovskite–based polycrystalline thin-film tandem solar cells have the potential to deliver efficiencies of >30%. However, the performance of all-perovskite–based tandem devices has been limited by the lack of high-efficiency, low–band gap tin-lead (Sn-Pb) mixed-perovskite solar cells (PSCs). We found that the addition of guanidinium thiocyanate (GuaSCN) resulted in marked improvements in the structural and optoelectronic properties of Sn-Pb mixed, low–band gap (~1.25 electron volt) perovskite films. The films have defect densities that are lower by a factor of 10, leading to carrier lifetimes of greater than 1 microsecond and diffusion lengths of 2.5 micrometers. These improved properties enable our demonstration of >20% efficient low–band gap PSCs. When combined with wider–band gap PSCs, we achieve 25% efficient four-terminal and 23.1% efficient two-terminal all-perovskite–based polycrystalline thin-film tandem solar cells.

Thiocyanate-Treated Perovskite-Nanocrystal-Based Light-Emitting Diodes with Insight in Efficiency Roll-Off

“…For another example, with inorganic halide ionic compounds pAssivating CsPbBr 3 NCs before purification with anti-solvent, the up-to-date highest EQE for perovskite NCs has been achieved [6]. Salts containing thiocyanate (SCN) have been demonstrated to be able to increase grain size and reduce defects in perovskite thin film [25] and have shown beneficial effects on stability [26], device performance and suppression of hysteresis in solar cell [27]. SCN, as a kind of pseudohalide, has also presented efficient pAssivation effect on perovskite NCs [28].…”

Reducing Photovoltage Loss in Inverted Perovskite Solar Cells by Quantum Dots Alloying Modification at Cathode Contact

“…Perovskite solar cells (PSCs) developed quickly in the past years, approaching power conversion efficiency (PCE) exceeding 25%, which was comparable with commercialized silicon solar cells . Particularly, PSCs with inverted planar structures have drawn great attention due to their low‐temperature solution‐process fabrication, which is compatible with roll‐to‐roll and flexible process and can be simply integrated into tandem solar cells . However, the device performance of inverted PSCs still lags behind that of regular structured PSCs, probably due to distinct open‐circuit voltage ( V OC ) loss induced by surface recombination .…”

Investigation of the effect of precursor ratios on the solution combustion synthesis of zinc zirconate nanocomposite

“…Earlier studies have shown that perovskite solar cells face challenges of stability and fast degradation in the environment. Recent studies and research have produced promising results towards the fabrication of commercially viable perovskite solar cells that will probably address these earlier challenges [13,14].…”