Researchers at the Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine and the University of Electronic Science and Technology of China (UESTC) have presented a simple and economical encapsulation strategy with shellac to protect perovskite solar cells (PSCs) under various accelerated degradation experiments. 

The shellac-encapsulated (SE) PSC modules reportedly passed outdoor stability, UV preconditioning, and hail tests according to the International Electrotechnical Commission 61215 standard (IEC61215). 

A collaborative team of researchers, including ones from Uppsala University, CNR-SCITEC, Fraunhofer ISE, University of Cambridge, Empa, EPFL and additional institutes, recently introduced an unexplored dimethylphenethylsulfonium iodide (DMPESI) molecule to post-treat formamidinium lead iodide perovskite films. The treated films showed outstanding stability upon light soaking and remarkably remains in black-phase after 2 years ageing under ambient condition without encapsulation. 

Fresh and 24-month aged unencapsulated perovskite film (1.0 cm by 2.0 cm) without and with DMPESI treatment of different concentrations. Image from Nature Energy

The DMPESI-treated PSCs deliver a breakthrough record in operational stability of highly-efficient PSCs with less than 1% performance loss after more than 4500 h at maximum power point tracking, yielding an extraordinarily high theoretical T80 of over 9 years under continuous 1-sun illumination, which would correspond to a photon flux of an outdoor PV installation in Sweden or Germany (1,000 kWh m−2 per year) of over 78 years. 

Researchers from China's Shanghai University of Engineering Science have developed a novel solar spectral converter using a GdPO₄ glass-ceramic (GC) material doped with praseodymium (Pr) and europium (Eu) ions. This technology could lead to notable boosts in performance and applicability of solar cells.

The main purpose of GdPO₄-GC:Eu³⁺/Pr³⁺ is to absorb UV photons from solar radiation and re-emit them as visible light. This is possible thanks to the efficient energy transfer that happens between the ions in the material.

Researchers at Germany's Forschungszentrum Jülich have reported a method to fabricate >1-micrometer thick perovskite films by employing hole-transporting bilayers of self-assembled monolayers (SAMs) and poly[bis(4-phenyl) (2,4,6-trimethylphenyl)amine] (PTAA). Recognizing the critical role transport layers play in exacerbating thickness-dependent losses, the team optimized a dual-layer hole transport architecture to reduce resistive losses and recombination. The authors achieved remarkable efficiency retention at over 1 micron thickness.

This work focuses on a solar cell architecture that decouples thickness from efficiency limitations. By sandwiching specialty organic films around the perovskite layer, the authors enabled micron-scale thicknesses without forfeiting peak performance. Their design notably achieves a remarkable 20.2% efficiency at over 1 micron thickness with minimal losses compared to thinner versions.

A team of researchers from Brookhaven National Lab, Georgia Institute of Technology, Argonne National Laboratory, Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta” (CNR-SCITEC) and Helmholtz-Zentrum Berlin für Materialien und Energie has examined the mechanism that causes degradation of formamidinium-based halide perovskites and have been able to stop it using a thin layer of molecules that repels water.

“Perovskites have the potential of not only transforming how we produce solar energy, but also how we make semiconductors for other types of applications like LEDs or phototransistors. We can think about them for applications in quantum information technology, such as light emission for quantum communication,” said Juan-Pablo Correa-Baena, assistant professor in the School of Materials Science and Engineering and the study’s senior author. “These materials have impressive properties that are very promising.”

Researchers at South Korea’s Chonnam National University have reported perovskite-organic hybrid tandem solar cells with 23.07% efficiency processed entirely in open air, bringing the technology a step closer to economic viability.

Schematic illustration of the synthesis of all-inorganic perovskite thin films by dynamic hot-air-assisted method. Image from Energy & Environmental Science 

Researchers have largely relied on meticulously engineering the perovskite crystal structure itself for greater resilience. But these delicate handling steps add cost and complexity not suitable for mass production. The team explained that the focus has recently shifted toward all-solution processed solar cells due to their low energy consumption fabrication processes. The team’s innovation, a dynamic hot air deposition technique, simplified the production process by eliminating the need for humidity-controlled environments.

Researchers in Sweden and China have studied the reasons behind the short operational lifetime of blue perovskite-based LEDs (PeLEDs). 

While perovskite light-emitting diodes (PeLEDs) have seen unprecedented development in device efficiency over the past decade, they still suffer from poor operational stability. This is especially true for blue PeLEDs, whose operational lifetime remains orders of magnitude behind their green and red counterparts. The scientists in this work have systematically investigated this efficiency-stability discrepancy in a series of green- to blue-emitting PeLEDs based on mixed Br/Cl-perovskites. Typically, mixed chloride/bromide perovskites are employed to produce ideal blue emission. However, the researchers have uncovered a counterintuitive fact: even minute quantities of chloride loading can have a dramatic negative impact on the operational lifetime of these devices. 

Researchers of Karlsruhe Institute of Technology (KIT) and of two Helmholtz platforms—Helmholtz Imaging at the German Cancer Research Center (DKFZ) and Helmholtz AI—have found a way to predict the quality of the perovskite layers and consequently that of the resulting solar cells. Using machine learning and new methods in artificial intelligence (AI), it is possible to assess their quality from variations in light emission already in the manufacturing process.

"Manufacturing these high-grade, multi-crystalline thin layers without any deficiencies or holes using low-cost and scalable methods is one of the biggest challenges," says tenure-track professor Ulrich W. Paetzold who conducts research at the Institute of Microstructure Technology and the Light Technology Institute of KIT.

Researchers at China's Wuhan University assume that the practical use of all-perovskite tandem solar cells is hampered by the subpar performance and stability issues associated with mixed tin–lead (Sn–Pb) narrow-bandgap perovskite subcells. In their recent study, they focus on these narrow-bandgap subcells and develop an all-in-one doping strategy for them. 

The scientists introduce aspartate hydrochloride (AspCl) into both the bottom poly(3,4-ethylene dioxythiophene)–poly(styrene sulfonate) and bulk perovskite layers, followed by another AspCl posttreatment. They show that a single AspCl additive can effectively passivate defects, reduce Sn⁴⁺ impurities and shift the Fermi energy level. 

Researchers at the Chinese Academy of Sciences (CAS), Beijing Normal University, Beijing Institute of Technology and ShanghaiTech University have developed a universal hydrogen-bonding-facilitated DMA extraction method to fabricate high-quality γ-CsPbI3 films. The researchers fabricated a solar cell based on cesium-lead iodide (CsPbI₃) perovskite, which is also known as black perovskite.

The black perovskite solar cell reportedly achieved  20.25% efficiency, which is said by the team to be the highest efficiency reported for PV devices built with this perovskite material and a dopant-free hole transport layer based on the P3HT polymer. The cell was also able to retain around 93% of its original efficiency after continuous illumination for 570 h.