• Energy Research

The molecular level interface engineering with a multifunctional ligand 2,5-thiophenedicarboxylic acid suppresses interfacial ion diffusion and inhibits I2 formation, which leads to high operational stability with T80 of 3570 h along with PCE of 23.4%.

AbstractOrganic–inorganic perovskite solar cells have achieved impressive power conversion efficiency over the past years, yet operational stability remains the key concern. One strategy to improve long‐term stability is to replace the thermally unstable organic with inorganic cations comprising the perovskite lattice. Here, for the first time, pulsed infrared light is used to drive the crystallization of inorganic mixed halide CsPbIxBr(3−x) perovskite films in solar cells with a power conversion efficiency exceeding 10%. By varying the iodide–bromine ratio systematically, it is found that to keep the inorganic perovskite black phase stable at the room temperature, the iodine content needs to be limited to lower than 60% – bromine content higher than 40%. The finding revises previous reports claiming stable compositions with higher iodine contents, which is systematically exploited to reduce the perovskite bandgap with the aim to enlarge the light absorption spectra and thus to boost the device efficiency. It is demonstrated that the newly defined stable compositional range enables devices that retain 90% of the efficiency after stressing the perovskite at 200 °C for 1 h. This result demonstrates that inorganic halide perovskites are stable materials for high‐temperature applications such as concentrated photovoltaics.

Organic-inorganic perovskites have an impressive potential for the design of next generation solar cells and are currently considered for upscaling and commercialization. Currently, perovskite solar cells rely on spin-coating which is neither practical for large areas nor environmentally friendly. Indeed, one of the conventional and most effective lab-scale methods to induce perovskite crystallization, the antisolvent method, requires an amount of toxic solvent that is difficult to apply on larger surfaces. To solve this problem, an antisolvent-free and rapid thermal annealing process called flash infrared annealing (FIRA) can be used to produce highly crystalline perovskite films. The FIRA oven is composed of an array of near-infrared halogen lamps with an illumination power of 3,000 kW/m2. A hollow aluminum body enables an effective water-cooling system. The FIRA method allows the synthesis of perovskite films in less than 2 s, achieving efficiencies >20%. FIRA has a unique potential for the industry because it can be adapted to continuous processing, is antisolvent-free, and does not require lengthy, hour-long annealing steps.

In this work, we elucidate the relationship between heating-rate and FAPbI3 perovskite phase transformation, bringing a new relationship with crystal growth parameters. Thus, we manufactured highly stable perovskite solar cells with a 640 ms IR pulse.

For successful commercialization of perovskite solar cells, straightforward solutions in terms of environmental impact and economic feasibility are still required. Flash Infrared Annealing (FIRA) is a rapid method to fabricate perovskite solar cells with efficiencies >18% on simple, planar architecture, which allows a film synthesis in only 1.2 s, faster than the previous report based in a meso architecture and all of them without the usage of antisolvent. In this work, through a comparative study with the common lab-scale method, the so-called antisolvent (AS), the main photovoltaic parameters and working mechanisms obtained from impedance spectroscopy (IS) measurements show similar device features as for FIRA. However, from the life cycle assessment (LCA) comparison study, the FIRA method has only 8% of the environmental impact and 2% of the fabrication cost of the perovskite active layer with respect to the AS for the perovskite film synthesis. These results denote that FIRA is a low-impact, cost-effective fabrication approach that can be directly adapted to perovskite planar configuration that is compatible with industrial up-scaling.

Integrating dye-sensitized solar cells with polyviologen-based supercapacitors enables efficient ambient light harvesting and storage, achieving 30% power conversion efficiency under indoor lighting conditions to power edge computing IoT networks.