August 2024

Researchers from the Chinese Academy of Sciences, Beijing Institute of Technology and Shanghai Lettee Perovskite Optoelectronic Technology have addressed the issue of residual tensile strain - which impedes the improvement of efficiency and intrinsic stability of perovskite solar cells (PSCs) (resulting from the perovskite lattice distortion and different thermal expansion coefficients). To this end, they proposed a molecule-triggered strain regulation and interfacial passivation strategy to enhance the efficiency and stability (especially photostability) of PSCs.

Their strategy utilizes the [2 + 2] cycloaddition reaction of 6-bromocoumarin-3-carboxylic acid ethyl ester (BAEE), consuming the incident UV light to suppress the tensile strain evolution. 

Researchers from China's Huazhong University of Science and Technology, Wuhan University of Technology and Huaneng Clean Energy Research Institute have reported a surface reconstruction strategy utilizing a surface polishing agent, 1,4-butanediamine, together with a surface passivator, ethylenediammonium diiodide, to eliminate Sn-related defects and passivate organic cation and halide vacancy defects on the surface of Sn–Pb mixed perovskite films. 

The team explained that while all-perovskite tandem solar cells have shown great promise in breaking the Shockley–Queisser limit of single-junction solar cell, their efficiency is often hindered by the surface defects induced non-radiative recombination loss in Sn–Pb mixed narrow bandgap perovskite films. The strategy detailed in their recent work not only delivers high-quality Sn–Pb mixed perovskite films with a close-to-ideal stoichiometric ratio surface, but also minimizes the non-radiative energy loss at the perovskite/electron transport layer interface.

An international team of researchers, including ones from the University of Sydney, IEK-5 Photovoltaics at Forschungszentrum Jülich, Southern University of Science and Technology, UNSW and the University of Ljubljana, recently reported the use of a piperidinium bromide (PpBr) as an interlayer between C60 and perovskite. The interlayer was further optimized by introducing an additional oxygen atom on the opposite side of the NH²⁺. 

The tandem structure that the team used for demonstrations. Image credit: Advanced Energy Materials

This reportedly resulted in morpholinium bromide (MLBr) with increased dipole moment. Because of this, MLBr was highly effective in minimizing the energy band mismatch between perovskite and C60 layer for electron extraction while at the same time passivating defects. 

Flexell Space, an in-house venture of Hanwha Systems, has announced that it has signed a letter of intent (LOI) with Airbus Defence and Space GmbH (Airbus) to develop next-generation space solar cell modules using perovskite/CIGS tandem solar cell technology. This collaboration aims to revolutionize the efficiency and weight of space solar cells, marking a significant milestone in the aerospace industry.

Through this agreement, Flexell Space and Airbus plan to design and develop space solar cell modules that are more than half the weight of existing models while maintaining performance and efficiency. By applying Flexell Space's tandem solar cell technology, the new solar cells will aim to offer low cost, high efficiency, rapid production, and flexibility.

Researchers from Shenzhen University recently addressed the stability issue of organic–inorganic hybrid perovskites, which the team says is currently a barrier to their widespread commercial application in optoelectronic devices. In addition to enhancing perovskite stability, the real-time detection of aging status, aimed at monitoring the aging progression, holds paramount importance for both fundamental research and the commercialization of organic–inorganic hybrid perovskites.

Schematic diagram of the THz-TDS system. Image from:  Frontiers of Optoelectronics 

In their recent work, the team examined the aging status of perovskite in real-time by using terahertz time-domain spectroscopy. This technique is based on the resonant absorption of terahertz waves by phonons in the perovskite. As perovskites age, the intensity of phonon vibration modes associated with the Pb-I bonds decreases, leading to changes in the absorption peaks of terahertz waves at specific frequencies. Based on this, they proposed using the intensity of these terahertz absorption peaks as an indicator to measure the ageing degree of perovskites in real-time.

As the area of perovskite films and devices increases, their performance tends to deteriorate - which researchers from the Chinese Academy of Science (CAS), University of Science and Technology of China and Dalian University of Technology explain can be linked to defects that accumulate at the bottom surface without proper passivation. In an attempt to address this issue, the team introduced a unique molecule (1-(4-Fluorophenyl)−2-pyrrolidone, or FPP) as an additive in large-area blade-coating perovskite films. 

During the top-down crystallization process, the FPP molecule forms an intermediate phase with the perovskite components and subsequently self-deposits at the bottom surface. Consequently, the crystallization kinetics of the large-area thin films are regulated, and the bottom surface is effectively and uniformly passivated in one single-step processing. 

Eindhoven University of Technology researchers have developed a multiscale computational framework for scaling up perovskite photovoltaics from cell scale to building integration. 

The novel framework includes three key modeling components: (i) cell scale, incorporating a coupled optical-electrical-thermal model to characterize performance and hysteresis of small-area perovskite solar cells, (ii) module scale, designing monolithically interconnected perovskite minimodules and quantifying upscaling losses, and (iii) building scale, assessing complex interactions between environmental factors and building-integrated perovskite photovoltaics.

Sekisui Chemical and TERRA recently announced that they have commenced the first joint demonstration test in Japan to install film-type perovskite solar cells for agrivoltaics (solar sharing) at Sosa City, Chiba Prefecture on August 2, 2024.

Sekisui Chemical has created a 30 cm-wide roll-to-roll manufacturing process utilizing its original “sealing, film formation, materials and process technology,” and has reportedly confirmed 10 years equivalent of outdoor durability, which is critical to the development of film-type perovskite solar cells. Furthermore, this manufacturing process has been successfully used to produce film-type perovskite solar cells with a power generation efficiency of 15.0%. Development is being accelerated to further improve durability and power generation efficiency, as well as to establish manufacturing technology for 1 m-wide rolls.

A collaborative project by leading Helmholtz Centers for photovoltaic research aims to accelerate the deployment of multi-benefit photovoltaics based on emerging printed PV-Technologies like organic photovoltaics and perovskites. 

Core Lab Perovskite PV at KIT. Image from Solar TAP website

The Solar Technology Acceleration Platform (Solar TAP) for emerging Photovoltaics brings together 3 Helmholtz Centers, 9 major research infrastructures, and more than 25 scientists. The three Helmholtz centers are: Forschungszentrum Jülich, Helmholtz Zentrum Berlin and Karlsruhe Institute of Technology. They are aligning their world-class infrastructures in order to create the joint Technology Acceleration Platform and providing fast and simple access to laboratories, equipment and scientists through collaborative pre-financed projects.

Hanwha Q CELLS, according to BusinessKorea, is shifting its strategy from research and development to rapid commercialization in the field of tandem solar cells. This strategic pivot comes, as was reported, as Chinese companies invest heavily in improving tandem energy efficiency.

Hanwha Q CELLS is reportedly set to complete the final inspection of its 40MW perovskite-tandem cell pilot line in Jincheon, Chungbuk, as early as October this year and begin trial operations. The company aims to start commercial production by 2026, believing that entering mass production ahead of China is crucial to gaining the upper hand in the market.