Perovskite applications - Page 3

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 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.

Researchers from Helmholtz Zentrum Berlin (HZB) and École Polytechnique Fédérale de Lausanne (EPFL) have presented optimization strategies for top cell processing and integration into silicon heterojunction (SHJ) bottom cells based on industrial Czochralski (Cz)-Si wafers of 140 μm thickness. 

Schematic illustration of the perovskite/silicon tandem solar cell based on 140 μm Cz-Si. Image credit: ACS Applied Materials & Interfaces

The team showed that combining the self-assembled monolayer [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) with an additional phosphonic acid (PA) with different functional groups, can improve film formation when used as a hole transport layer improving wettability, minimizing shunt fraction and reducing nonradiative losses at the buried interface. 

Perovskite solar cells (PSCs) that incorporate a 2D/3D perovskite layer tend to demonstrate enhanced stability compared to that of their purely 3D counterparts, possibly thanks to the superior chemical stability of the 2D perovskite layer. However, the poor electrical properties of the 2D perovskite layer also limit further improvement of device performance. Moreover, the most effective hole transport layer (HTL) in 2D/3D PSCs, lithium bis(trifluoromethylsulfonyl)imide (Li-TFSI)-doped 2,2′,7,7′-tetrakis(N,N-di(4-methoxyphenyl)amino)-9,9-spirobifluorene (spiro-OMeTAD), usually needs prolonged exposure to air to improve its conductivity, which to some extent increases the risk of water/oxygen infiltrating into the perovskite layer, leading to the degradation of the perovskite active layer.

Researchers at China's Henan University and Chinese Academy of Sciences (CAS) have developed a multifunctional dopant, tin oxysulfide (SnSO) in the spiro-OMeTAD layer, to improve the efficiency and stability simultaneously.

Researchers from Australia’s University of New South Wales (UNSW) Sydney have developed a defects passivation strategy for chloride-iodide-based perovskite. The team targeted the hard-to-avoid local defects in chloride-iodide-based perovskites, using two organic halide passivators named 4-chlorobenzylammonium chloride and 4-chlorobenzylammonium bromide. 

The scientists passivate both the surface and bulk of the perovskite thin film. The surface of the perovskite thin film is passivated with the bulky organic benzylammonium cations. The bulk of the perovskite thin film is passivated with the diffusion of chlorine or bromine. 

Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE), an Energy Frontier Research Center (EFRC), University of Wisconsin-Madison, University of Colorado Boulder, Duke University and University of Utah have discovered a new process to induce chirality in halide perovskite semiconductors, which could open the door to cutting-edge electronic applications.

The development is the latest in a series of advancements made by the team involving the introduction and control of chirality. Chirality refers to a structure that cannot be superimposed on its mirror image, such as a hand, and allows greater control of electrons by directing their “spin.” Most traditional optoelectronic devices in use today exploit control of charge and light but not the spin of the electron.