Improved Carrier Management via a Multifunctional Modifier for High‐Quality Low‐Bandgap Sn–Pb Perovskites and Efficient All‐Perovskite Tandem Solar Cells

Abstract

All-perovskite tandem solar cells (TSCs) hold great promise in terms of ultrahigh efficiency, low manufacturing cost, and flexibility, stepping forward to the next-generation photovoltaics. However, their further development is hampered by the relatively low performance of low-bandgap (LBG) tin (Sn)-lead (Pb) perovskite solar cells (PSCs). Improving the carrier management, including suppressing trap-assisted non-radiative recombination and promoting carrier transfer, is of great significance to enhance the performance of Sn-Pb PSCs. Herein, a carrier management strategy is reported for using cysteine hydrochloride (CysHCl) simultaneously as a bulky passivator and a surface anchoring agent for Sn-Pb perovskite. CysHCl processing effectively reduces trap density and suppresses non-radiative recombination, enabling the growth of high-quality Sn-Pb perovskite with greatly improved carrier diffusion length of >8 μm. Furthermore, the electron transfer at the perovskite/C 60 interface is accelerated due to the formation of surface dipoles and favorable energy band bending. As a result, these advances enable the demonstration of champion efficiency of 22.15% for CysHCl-processed LBG Sn-Pb PSCs with remarkable enhancement in both open-circuit voltage and fill factor. When paired with a wide-bandgap (WBG) perovskite subcell, a certified 25.7%-efficient all-perovskite monolithic tandem device is further demonstrated.

Halide perovskite photovoltaic-electrocatalysis for solar fuel generation

“…Luo et al report a carrier management strategy for using cysteine hydrochloride (CysHCl) to improve carrier management, which can suppress trap-assisted non-radiative recombination and promote carrier transfer. 126 CysHCl simultaneously acts as a bulky passivator and a surface anchoring agent for Sn–Pb perovskite. They introduced trace amounts of CysHCl into the NBG perovskite precursor solution and coated the CysHCl solution on top of the perovskite layer.…”

Advancing Efficiency and Stability of Lead, Tin, and Lead/Tin Perovskite Solar Cells: Strategies and Perspectives

“…Importantly, it achieved 18.0% PCE with a large area (10 cm 2 ) device with significantly improved device stability under ambient conditions (ISOS-D-1) for nonencapsulated modules. [238] A hydride method with molecular passivation and additive engineering has also been used in Sn-Pb-HPSCs, [10,237,241,[252][253][254][255] a good example of this coming from the Wakamiya group, where they used 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (TM-DHP) as a functional additive and 3-hydroxy-2-methyl-4-pyrone (Maltol) surface treatment for the fabrication of Sn-Pb HPSCs. They demonstrated enhancement in PCE from 18.2 to 21.4% benefiting from high-quality HP and enhanced charge carrier lifetime.…”

“…However, recent reports have demonstrated significant progress on perovskite/perovskite tandem devices. [254,[270][271][272] For example, Tan and co-workers have achieved a certified PCE of 26.4% in all-perovskite tandem HPSCs with improved grain surface passivation using multifunctional molecules (e.g., 4-trifluoromethyl-phenylammonium halide) which exceeded the record PCE of the single-junction HPSCs. [273] Furthermore, the same group reported all-perovskite tandem HPSCs with 3D/2D bilayer perovskite heterojunction fabricated by adopting a hybrid evaporation/solution processing method.…”

Reduced electron relaxation time of perovskite films via g-C3N4 quantum dot doping for high-performance perovskite solar cells

“…Organic–inorganic hybrid perovskite solar cells (PSCs) have attracted intensive attention in the last few years due to outstanding photoelectric properties of perovskite semiconductor materials such as longer exciton diffusion length, higher absorption coefficient and easier tunable direct bandgap, 1–3 which have promoted high power conversion efficiencies (PCEs) of PSCs to the current world record of 25.7% (ref. 4) based on a single junction device. Particularly, the perovskite light-absorbing layer attracts much attention by its simple and low-temperature fabrication technology.…”