Triple-cation perovskite solar cells, such as Cs_0.05(FA_0.83MA_0.17)_0.95Pb(I_0.83Br_0.17)₃ (hereinafter referred to as CsFAMA) have high efficiency (>26%), but their stability is limited by phase segregation and defects at grain boundaries. In this work, the effect of formic acid (HCOOH) on suppressing the degradation of perovskite films is investigated. It is shown that the addition of HCOOH to the precursor solution reduces the size of colloidal particles by 90%, which contributes to the formation of highly homogeneous films with a photoluminescence intensity deviation of ≤3%. Structural analysis and dynamic light scattering measurements confirmed that HCOOH suppresses iodide oxidation and cation deprotonation, reducing the defect density. Aging tests (ISOS-D) demonstrated an increase in the T80 lifetime (time to 80% efficiency decline) from 158 to 320 days for the modified cells under ambient conditions at room temperature and 40% relative humidity. The obtained results indicate a key role of HCOOH in stabilizing CsFAMA perovskite by controlling colloidal dynamics and defect passivation, which opens up prospects for the creation of commercially viable PSCs.

Subject of study. Solar cells based on CsPbI₃ and CsPbBr₃ photosensitive inorganic perovskites are investigated. Aim of study. The study aimed to simulate and fabricate inorganic perovskite solar cells based on CsPbI₃ and CsPbBr₃. Method. A theoretical study was conducted using the open-source AFORS-HET program, which is designed for one-dimensional modeling of solar cells and other optoelectronic devices. During the fabrication of the structures, various equipment, including an EZ4 spin coater for thin film and photoresist deposition, ULAB US-1500D heated laboratory magnetic stirrers, and a vacuum thermal deposition station, was employed. Main results. Solar cells based on CsPbI₃ and CsPbBr₃ photosensitive inorganic perovskites were simulated using the AFORS-HET software. The primary photovoltaic cell parameters, including the fill factor, short-circuit current, open-circuit voltage, and efficiency, were estimated. A theoretical analysis was performed to identify the factors and defects in the perovskite films affecting the solar cells’ performance. Based on the simulation results, photosensitive structures using CsPbI₃ were fabricated and characterized. Practical significance. The studied solar cells based on CsPbI₃ and CsPbBr₃ exhibit potential as efficient solar-to-electrical energy converters.

In this work, CsPbBr₃ perovskite quantum dots (QDs) were synthesised by hot injection, with reaction time controlling nanocrystal size and emission from 493 to 515 nm. Temperature-dependent photoluminescence (23–80 °C) showed decreasing intensity but stable peak position. Embedding QDs in PMMA and PVK revealed polymer-dependent thermal behaviour: insulating PMMA preserved radiative recombination and gave stable, reproducible quenching, while semiconducting PVK introduced interfacial charge transfer, enhancing thermal sensitivity. The results establish CsPbBr₃ QD–polymer composites as tunable temperature-sensitive platforms for optical sensing.