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.

Subject of study. This study investigated photosensitive structures with a planar heterojunction based on copper phthalocyanine and 3,4,9,10-perylenetetracarboxylic dianhydride. Aim of study. The aim of this study was to develop organic photosensitive structures based on metal phthalocyanine and a non-fullerene acceptor. Method. Photosensitive structures were fabricated using vacuum thermal deposition. Absorption and photocurrent spectra of these structures were measured. Main results. The optimal parameters for fabricating organic photosensitive structures using a non-fullerene acceptor were determined. The optimal substrate heating temperatures, which influence the quality of the deposited layers, were 60°C and 55°C for copper phthalocyanine and 3,4,9,10-perylenetetracarboxylic dianhydride, respectively. The primary contribution to the photoresponse of the structure was determined to be the charge-carrier generation in copper phthalocyanine. The influence of the evaporated donor mass on the photosensitivity spectra of the structures was also determined. The studied structures exhibited a photoresponse in the energy range of 1.35–2.45 eV. Practical significance. The results of this work can be used in the development of photodetectors based on organic materials for the visible and near-infrared spectral ranges for applications in communication systems, visualization, spectroscopy, medical diagnostics, and other fields. In addition, the developed structures incur lower production costs compared to devices based on conventional inorganic semiconductors.

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.

The process of creating a photosensitive structure with a double-distributed heterojunction based on a combination of fullerene and non-fullerene acceptors (PC71BM and ITIC-F) is described in this work. P3HT was used as the donor in both layers. The spectral photosensitivity response of the resulting FTO/P3HT:ITIC-F/P3HT:PC71BM/InGaSn structure covers a wide range of 470–980 nm. The peak photosensitivity of the structure reaches 40.98 mA/W, which is many times higher than the values for structures based on individual layers and a blend of all materials in one bulk heterojunction. The studies and measurements show that such a structure can be used in optics and electronics to detect radiation in the visible and near-IR ranges. In addition, the principle of creating a double-distributed heterojunction structure used in this study can be applied to other organic materials to obtain previously unattainable performance levels.