Search academic texts

Information × Registration Number 0226U000989, (0124U002141) , R & D reports Title Multilayer structures with organic polymer semiconductor heterojunctions and Si photon crystal based backside reflectors for photoelectric solar energy converters popup.stage_title Розробка технології виготовлення фотоелектричних перетворювачів з гетеропереходами з органічними шарами та тиловими рефлекторами на основі фотонних кристалів. Підготовка матеріалів для публікації Дослідження характеристик виготовлених фотоперетворювачів та оптимізація технології їх отримання. Підготовка матеріалів для публікації. Head Sarikov Andrii V., Доктор фізико-математичних наукSkryshevskyi Valerii A., д.ф.-м.н. Registration Date 19-01-2026 Organization Department for special training National academy of science of Ukraine at Kiev University popup.description1 To develop a hybrid photoconverter based on organic and polymer heterojunctions with backside porous photonic crystal reflectors. Organic semiconductor photoconverters are a cheap alternative to traditional Si solar cells (SCs). Their production requires investigations to improve the efficiency, increase the lifetime, and reduce cost. In this work, new promising organic semiconductor materials of the melanin family to apply as SC active layers will be investigated. Porous photonic crystals (PFCs) will be used for the first time as controllable backside reflectors to increase the organic SC efficiency. In this work, the PFCs will be functionalized with nanoparticles and polymer to ensure spectral response in the given spectral range and obtain the required mechanical properties. popup.description2 Using IR spectroscopy and chemical structure modeling, the type of eumelanin molecules obtained by the patented method, namely 5,6-dihydroxyindole-2-carboxylic acid (DHICA), is identified. The mechanism of water solubility is proposed based on formation of a carboxyl group anion through the use of ammonia water for extracting melanin. A method for obtaining water-insoluble DHICA by protonation of the carboxyl group by adding HCl to a melanin aqueous solution is proposed. It is found that a water-soluble melanin film sandwiched between a transparent conductive contact and porous Si layer is conductive, with the ion-electron conductivity mechanism. A water-insoluble melanin film obtained from a solution in dimethyl sulfoxide (DMSO) has higher absorption coefficient and electron-ionic conductivity mechanism. Based on both DHICA polymer film types on a Si substrate with a top porous layer, photovoltaic converters with the efficiencies of 0.03 % and 4.4 %, respectively, are created. A method of controlled etching porous Si layers and multilayer structures with refractive indices nPS in the range of 1.6..2.3 is developed. Formation of the layers with nPS < 1.6 is shown to increase the effect of chemical etching, while the layers with nPS > 2.3 are physically unstable. A software for modeling the reflection spectra of photonic crystals in the range of 300...1200 nm as well as for automated processing of their spectral characteristics is developed. The dependence of the reflection spectra of the rear reflectors on the refractive indices of the layers [nL, nH], the number of bi-layers, the difference nH – nL, the position of the maximum of the Bragg reflector, and the Bragg reflector with a microslit is determined. The width of the Bragg peak of the photonic crystal is shown to increase with a shift of λ0 toward longer wavelengths and with an increase in nH – nL. The reflection coefficient within the Bragg peak approaches 100% at the number of bi-layers exceeding 8. Product Description popup.authors Ivanov Ivan I. Mariia V. Voytovych Mykola O. Semenenko Shahan Serhii V. Lysenko Artemii V. Oleksandr Y. Ostapenko popup.nrat_date 2026-01-19 Close