Technical / research - Page 2

Researchers from Zhejiang University, Soochow University, King Abdullah University of Science and Technology (KAUST), The Hong Kong Polytechnic University and Suzhou Maxwell Technologies have addressed common challenges related to hole transport layers that are commonly used for the perovskite top cells, such as defects, non-conformal deposition or de-wetting of the overlying perovskite on the textured silicon bottom cells.

The team decided to develop a strategy based on co-deposition of copper(I) thiocyanate and perovskite, where effective perovskite grain boundary passivation and efficient hole collection are simultaneously achieved by the embedded copper(I) thiocyanate, which creates local hole-collecting contacts. Fabricated monolithic perovskite/silicon tandem devices achieved a certified power conversion efficiency of 31.46% for 1 cm² area devices. 

A Research Group led by Prof. Eva Unger at Helmholtz Zentrum Berlin (HZB), in collaboration with the Indian Institute of Technology Bombay and University of Jammu, has reported the use of inkjet printing to fabricate thin films of combinatorial mixed formamidinium tin-lead perovskites and evaluated their layer quality and device performance. The team focused on optimizing the inkjet-printing process to ensure precise film deposition and enhance device performance.

Image credit: ACS Applied Materials and Interfaces

The scientists deposited Sn/Pb intermixed FASn_1–xPb_xI₃ (x = 0.25, 0.5, and 0.75)-based perovskite thin films through inkjet printing. The study focused on finding the ideal composition ratio for a favorable photovoltaic performance. The deposited FASn_1–xPb_xI₃ thin films were subjected to various characterizations followed by their implementation in solar cells. 

The certified efficiency of 1 cm² scale all-perovskite tandem solar cells tends to lag behind that of their small-area (~0.1 cm2) counterparts. This performance deficit originates from inhomogeneity in wide-bandgap (WBG) perovskite solar cells (PSCs) at a large scale. The inhomogeneity is thought to be introduced at the bottom interface and within the perovskite bulk itself. 

Researchers from Nanjing University, Jilin University, University of Cambridge, University of Victoria, The Australian National University, Chinese Academy of Sciences (CAS) and Renshine Solar (Suzhou) have reported an all-perovskite tandem solar cell based on a wide-bandgap top perovskite cell with a 20.5% efficiency. 

Researchers from the Universitat Internacional de Catalunya (UIC), University of Rome Tor Vergata and Université Crenoble Alpes have designed a Solar Brick (SB) based on textile ceramic technology (TCT) and perovskite photovoltaic cells. The new SB can be used for applications in building-integrated photovoltaics (BIPV). 

Textile Ceramic Technology (TCT) is an innovative construction system that consists of ceramic units installed in a grid of stainless steel wires. TCT has been patented in 2011. Its main application is to cover roofs, grounds, building façades and more. The team says: "One of the advantages of the system is the reduced time construction, since traditional ceramic claddings systems require a manual procedure on site in where the bricks are placed one by one joined by mortar. Moreover, the large length dimension of the shells makes possible to cover ground, façade and roof with the same element".

Researchers at the University of Tsukuba and Kyoto University have studied the internal properties of low-cost materials used in perovskite solar cells that use HND-2NOMe, a replacement hole-transport material to spiro-OMeTAD, using electron spin resonance (ESR) to analyze these materials at a microscopic level.

Chemical structures of hole-transport materials spiro-OMeTAD and HND-2NOMe. Image from: Communications Materials

The results clarify the underlying causes for reduced device performance, despite high local charge mobility, offering critical insights for designing improved solar cells. 

Zinc-ion batteries (ZIBs) are emerging as a candidate for use as an efficient and sustainable energy storage solution, offering advantages in terms of cost-effectiveness, safety, and performance. The key to commercializing ZIBs lies in developing cathode materials that offer high specific capacity and prolonged cycle performance. 

In a recent study, researchers from the Indian Institute of Science and University of Melbourne have demonstrated the capability of environmentally friendly, lead-free inorganic perovskites for high-rate rechargeable aqueous zinc-ion batteries with enhanced stability and excellent rate performance.

Researchers from China's Tianshui Normal University have reported a grain regeneration and passivation approach that can decrease the recombination loss of the perovskite layer/charge transfer layer interface and the grain border. 

Device manufacturing process. Image from: Scientific Reports

The team relies on guanidine iodide (GAI) treatment of perovskite films for this new approach. Unlike most methods that use GAI for post-treatment of the perovskite layer or add GAI into the perovskite precursor solution, this work uses GAI for pre-treatment before spin coating the perovskite layer. It can effectively passivate surface defects and increase the grain size of perovskite films by controlling the crystallization process. 

Researchers from the  Chinese Academy of Sciences (CAS) and Zhejiang University have developed a highly passivated TOPCon bottom cell, achieving perovskite/silicon tandem solar cells (TSCs) with high open-circuit voltages (VOCs) and excellent efficiencies. 

The structure and performance of tandem devices with highly passivated TOPCon bottom cells. Image by Ningbo Institute of Materials Technology and Engineering (NIMTE) 

Numerous defects at the fragile silicon oxide/c-Si interface and the weak field-effect passivation on textured substrates reduce the VOCs of current TOPCon silicon solar cells, thus limiting their application for high-performance perovskite/silicon TSCs. In this study, the researchers prepared highly passivated p-type TOPCon structures and double-sided TOPCon bottom cells on industrial textured wafers via industry-compatible fabrication methods, including ambient-pressure thermal oxidation and in situ plasma-enhanced chemical vapor deposition.

Researchers from South Korea's Jeonbuk National University examined the use of slot die coating (SDC) to make uniform high-quality perovskite films as a step towards large-area perovskite device manufacturing.

Schematic illustration of the perovskite lab cell-sized module. Image credit: Communications Materials

The team found that SDC increased the roughness of the hole transport layer (HTL) interface, which improved the wettability of the surface, enabling a high-quality perovskite film without bubbles or pinholes. A perovskite solar cell based on the film achieved 19.17% efficiency with “excellent” stability results, and a lab cell-sized module achieved 17.42% efficiency.

Researchers at the Korea Advanced Institute of Science and Technology (KAIST), Yonsei University, Gwangju Institute of Science and Technology (GIST) and Korea Institute of Ceramic Engineering and Technology (KICET) have reported a high-efficiency and high-stability organic-inorganic hybrid solar cell production technology that maximizes near-infrared light capture beyond the existing visible light range.

The research team suggested a hybrid next-generation device structure with organic photo-semiconductors that complements perovskite materials limited to visible light absorption and expands the absorption range to near-infrared. In addition, they focused on a common issue that mainly occurs in the structure and developed a solution to this problem by introducing a dipole layer - a thin material layer that controls the energy level within the device to facilitate charge transport and forms an interface potential difference to improve device performance.