Technical / research

Small-molecule ionic liquids are frequently used as efficient bulk phase modifiers for perovskite materials. However, their inherent characteristics, such as high volatility and ion migration, pose challenges in addressing the stability issues associated with perovskite solar cells (PSCs). Recently, researchers at China's Northwestern Polytechnical University and CNPC Tubular Goods Research Institute designed improved poly ionic liquids (ILs) with multiple active sites as efficient additives for perovskite materials.

The team's recent work shows how additive engineering with a polymerized ionic liquid to the metal halide perovskite material can improve the solar cell's function, helping to pave the way for the adoption of perovskite solar cells.

Researchers from EPFL, CSEM and Empa have demonstrated a cell design combining additive and substrate engineering that yields consistently high power conversion efficiencies and discussed various design aspects that are important for reproducibility and performance. 

The team presented two key developments with a synergetic effect that boost the PCEs of tandem devices with front-side flat Si wafers—the use of 2,3,4,5,6-pentafluorobenzylphosphonic acid (pFBPA) in the perovskite precursor ink that suppresses recombination near the perovskite/C60 interface and the use of SiO₂ nanoparticles under the perovskite film that suppress the enhanced number of pinholes and shunts introduced by pFBPA, while also allowing reliable use of Me-4PACz as a hole transport layer. 

Researchers at China's Shanghai University of Electric Power have used dibenzoylmethane (DBM) as a precursor additive introduced in order to regulate the crystallization of CsPbI₂Br perovskite while passivating its associated defects. 

Inorganic CsPbI₂Br perovskite solar cells (PSCs) have attracted massive interest but the tendency towards unruly crystallization and poor film quality of inorganic CsPbI₂Br perovskites are major factors limiting their performance improvement. In their recent work, the scientists used DBM additive engineering for efficient and stable carbon-based CsPbI₂Br PSCs.

A recent collaboration between the Hybrid³ team at Duke University (led by Professor Volker Blum) and SpringerMaterials has resulted in an insightful project called the Hybrid Perovskite Data Set, which enables researchers to compare and analyze different materials and optimize their properties for specific applications.

The huge number of variations of perovskite materials can make it challenging to find the most suitable material for a specific application. Now, researchers can use the data set to design new materials and experiment with new compositions, making the discovery of new materials more efficient and effective.

Researchers from India's Chiktara University have reported improved stability and performance of organic-inorganic perovskite solar cells by applying a strategy called bandgap grading.

The method is based on enabling the cell perovskite absorber to collect a wider range of light photons by modifying its thickness and characteristics. The team explains that its recent study demonstrates the effectiveness of both linear and parabolic bandgap grading strategies in optimizing light absorption and boosting performance, showing its potential. 

Researchers from the Hong Kong University of Science and Technology, Sun Yat-sen University and Nanjing University of Science and Technology have uniformly grown all-inorganic perovskite quantum wire arrays by filling high-density alumina nanopores on the surface of Al fibers with a dip-coating process. 

Fiber light-emitting diodes (Fi-LEDs), which can be used for wearable lighting and display devices, could be a key component for fiber/textile electronics. However, as a number of challenges exist with this technology, researchers are trying to address issues like on device fabrication with fiber-like substrates, as well as on device encapsulation.

Researchers at China's Nanjing University of Science and Technology, Hong Kong Baptist University and Southwest University have introduced a tandem device that incorporates an organic photodiode (OPD) and a perovskite light emitting diode (PeLED), enabling simultaneous light detection and emission in one compact device, prepared by all-solution fabrication process. 

The team found that precise control of interfacial properties plays a critical role in establishing the all-solution processed OPD/PeLED multi-layered dual-function device which is critical for charge transport, recombination, and generation. 

Researchers from Germany's Karlsruhe Institute of Technology (KIT) have developed a scalable two-step evaporation and inkjet process for perovskite thin-film solar cells. The new technique is said to enable champion cells with the same efficiencies as those made with the spin coating process.

The process is described as a scalable and reliable technique for high-quality perovskite deposition, which combines the use of an evaporated lead iodide layer with inkjet-printed organic perovskite precursor materials. It is also said to exhibit high reproducibility and potential for conformal growth on textured silicon, and that provide films that are free of drying effects and toxic solvents.

Researchers from Korea's Daegu Gyeongbuk Institute of Science and Technology (DGIST), Ulsan National Institute of Science and Technology (UNIST) and Institute for Basic Science (IBS) recently developed high-performance, skin-attachable perovskite pure red light-emitting devices to create various forms of wearable displays.

The team developed these devices through selective surface modification of perovskite quantum dots, expecting their future use in diverse wearable products. As traditional red perovskite materials were unsuitable for high-performance wearable displays due to their low stability and electrical properties, the research team created pure red light-emitting devices through the simple surface modification of the perovskite light-emitting layers, thus significantly improving their stability and electrical properties.

Researchers from EPFL, Soochow University, Chinese Academy of Sciences, Lomonosov Moscow State University, Luxembourg Institute of Science and Technology (LIST), Julius Maximilian University of Würzburg, Toin University of Yokohama, Southern University of Science and Technology, Xi’an Jiaotong University, North China Electric Power University and Toyota Motor Europe recently developed a solar panel relying on EPFL's record-breaking 25.32%-efficient 2D/3D perovskite solar cells unveiled in July 2023.

The group's research demonstrates a larger surface area of 27.22 cm², achieving an impressive efficiency of 23.3%. In the paper, the scientists explain that the module's high efficiency was achieved thanks to a synergistic dopant-additive combination strategy aimed to improve the cell absorber's uniformity and crystallinity. They used, in particular, methylammonium chloride (MACl) as a dopant and a Lewis-basic ionic liquid known as 1,3-bis(cyanomethyl)imidazolium chloride ([Bcmim]Cl) as an additive.