Chen Weijie

Tri-cation and dual-anion mixed perovskites have been widely utilized in perovskite solar cell (PSC) applications due to their novel properties such as high absorption, high stability, and low cost. To commercialize the PSCs, further improving the device performance without detrimentally changing the device configuration is important at present. Herein, Au@SiO₂ nanoparticles (NPs) are introduced to modify the interface between mesoporous TiO₂ (mp-TiO₂) and mixed perovskite with increased main photovoltaic parameters of the device, resulting in a ≈29% enhancement of power conversion efficiency (PCE) from 15.8% to 20.3%. The origins of the enhancement have been studied by exploring the optical absorption, optical power distribution, and charge carrier behaviors within the system. The small perturbation transient photovoltage measurement exhibits prolonged charge carrier lifetimes after the Au@SiO₂ NPs incorporation, and time of flight photoconductivity measurement shows that charge carrier mobilities of this system are also enhanced. These characteristics make metallic nanostructures a promising functional material in facile tuning of the charge carriers transport and further boosting the PCE of the PSCs.

Au@SiO₂ core−shell nanoparticles are incorporated into perovskite solar cells based on tri-cation (cesium, methylammonium, and formamidinium) and dual-anion (Br and I) mixed perovskite. Significant enhancements are observed in nearly all photovoltaic parameters after Au@SiO₂ nanoparticles incorporation. The enhanced device performance can be ascribed to the light absorption enhancement, more efficient carrier injection/transport, and the enhanced charge carriers mobilities.

Despite the recent unprecedented increase in the power conversion efficiencies (PCEs) of small-area devices (≤0.1 cm²), the PCEs deteriorate drastically for PSCs of larger areas because of the incomplete film coverage caused by the dewetting of the hydrophilic perovskite precursor solutions on the hydrophobic organic charge-transport layers (CTLs). Here, an innovative method of fabricating scalable PSCs on all types of organic CTLs is reported. By introducing an amphiphilic conjugated polyelectrolyte as an interfacial compatibilizer, fabricating uniform perovskite films on large-area substrates (18.4 cm²) and PSCs with the total active area of 6 cm² (1 cm² × 6 unit cells) via a single-turn solution process is successfully demonstrated. All of the unit cells exhibit highly uniform PCEs of 16.1 ± 0.9% (best PCE of 17%), which is the highest value for printable PSCs with a total active area larger than 1 cm².

Large-area planar perovskite solar cells (PSCs) are demonstrated by an innovative method using an amphiphilic conjugated polyelectrolyte as an interfacial compatibilizer between the hydrophobic organic charge-transport layer and hydrophilic perovskite layer. Highly scalable PSCs with uniform perovskite films on a large-area substrate (18.4 cm²) and with an active area of 1 cm² exhibit stabilized power conversion efficiencies of 17%.

In article number 1604695, Wallace C.H. Choy and co-workers propose a novel room-temperature scheme of pyridine-promoted formation of perovskite films featuring large grain-sizes, and high crystallinity, while being free of residues. This new approach enables the fabrication of all room-temperature, solution-processed perovskite solar cells (PVSCs) with a record efficiency of 17.10% and 14.19%, with no hysteresis on rigid and flexible substrate respectively.