Polymeric Materials for Conversion of Electromagnetic Waves from the Sun to Electric Power

Advances in organic photovoltaic cells: a comprehensive review of materials, technologies, and performance

This paper provides a comprehensive overview of organic photovoltaic (OPV) cells, including their materials, technologies, and performance. In this context, the historical evolution of PV cell technology is explored, and the classification of PV production technologies is presented, along with a comparative analysis of first, second, and third-generation solar cells. A classification and comparison of PV cells based on materials used is also provided. The working principles and device structures of OPV cells are examined, and a brief comparison between device structures is made, highlighting their advantages, disadvantages, and key features. The various parts of OPV cells are discussed, and their performance, efficiency, and electrical characteristics are reviewed. A detailed SWOT analysis is conducted, identifying promising strengths and opportunities, as well as challenges and threats to the technology. The paper indicates that OPV cells have the potential to revolutionize the solar energy industry due to their low production costs, and ability to produce thin, flexible solar cells. However, challenges such as lower efficiency, durability, and technological limitations still exist. Despite these challenges, the tunability and versatility of organic materials offer promise for future success. The paper concludes by suggesting that future research should focus on addressing the identified challenges and developing new materials and technologies that can further improve the performance and efficiency of OPV cells.

Surface Modification of ZrO2 Nanoparticles with TEOS to Prepare Transparent ZrO2@SiO2-PDMS Nanocomposite Films with Adjustable Refractive Indices

Here, highly transparent nanocomposite films with an adjustable refractive index were fabricated through stable dispersion of ZrO₂ (n = 2.16) nanoparticles (NPs) subjected to surface modification with SiO₂ (n = 1.46) in polydimethylsiloxane (PDMS) (n = 1.42) using the Stöber method. ZrO₂ NPs (13.7 nm) were synthesized using conventional hydrothermal synthesis, and their surface modification with SiO₂ (ZrO₂@SiO₂ NPs) was controlled by varying the reaction time (3–54 h). The surface modification of the NPs was characterized using Fourier-transform infrared spectroscopy, dynamic light scattering, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and ellipsometry. The surface modification was monitored, and the effective layer thickness of SiO₂ varied from 0.1 nm to 4.2 nm. The effective refractive index of the ZrO₂@SiO₂ NPs at λ = 633 nm was gradually reduced from 2.16 to 1.63. The 100 nm nanocomposite film was prepared by spin-coating the dispersion of ZrO₂@SiO₂ NPs in PDMS on the coverslip. The nanocomposite film prepared using ZrO₂@SiO₂ NPs with a reaction time of 18 h (ZrO₂@SiO₂-18h-PDMS) exhibited excellent optical transparency (T_average = 91.1%), close to the transparency of the coverslip (T_average = 91.4%) in the visible range, and an adjustable refractive index (n = 1.42–1.60) as the NP content in the film increased from 0 to 50.0 wt%.

Simulation of time-resolved x-ray absorption spectroscopy of ultrafast dynamics in particle-hole-excited 4-(2-thienyl)-2,1,3-benzothiadiazole

To date, alternating co-polymers based on electron-rich and electron-poor units are the most attractive materials to control functionality of organic semiconductor layers in which ultrafast excited-state processes play a key role. We present a computational study of the photoinduced excited-state dynamics of the 4-(2-thienyl)-2,1,3-benzothiadiazole (BT-1T) molecule, which is a common building block in the backbone of π-conjugated polymers used for organic electronics. In contrast to homo-polymer materials, such as oligothiophene, BT-1T has two non-identical units, namely, thiophene and benzothiadiazole, making it attractive for intramolecular charge transfer studies. To gain a thorough understanding of the coupling of excited-state dynamics with nuclear motion, we consider a scenario based on femtosecond time-resolved x-ray absorption spectroscopy using an x-ray free-electron laser in combination with a synchronized ultraviolet femtosecond laser. Using Tully's fewest switches surface hopping approach in combination with excited-state calculations at the level of configuration interaction singles, we calculate the gas-phase x-ray absorption spectrum at the carbon and nitrogen K edges as a function of time after excitation to the lowest electronically excited state. The results of our time-resolved calculations exhibit the charge transfer driven by non-Born-Oppenheimer physics from the benzothiadiazole to thiophene units during relaxation to the ground state. Furthermore, our ab initio molecular dynamics simulations indicate that the excited-state relaxation processes involve bond elongation in the benzothiadiazole unit as well as thiophene ring puckering at a time scale of 100 fs. We show that these dynamical trends can be identified from the time-dependent x-ray absorption spectrum.

Testing Anti-Biofilm Polymeric Surfaces: Where to Start?

Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.

Structure-Function Relationship of Organic Semiconductors: Detailed Insights From Time-Resolved EPR Spectroscopy

Organic photovoltaics (OPV) is a promising technology to account for the increasing demand for energy in form of electricity. Whereas the last decades have seen tremendous progress in the field witnessed by the steady increase in efficiency of OPV devices, we still lack proper understanding of fundamental aspects of light-energy conversion, demanding for systematic investigation on a fundamental level. A detailed understanding of the electronic structure of semiconducting polymers and their building blocks is essential to develop efficient materials for organic electronics. Illuminating conjugated polymers not only leads to excited states, but sheds light on some of the most important aspects of device efficiency in organic electronics as well. The interplay between electronic structure, morphology, flexibility, and local ordering, while at the heart of structure-function relationship of organic electronic materials, is still barely understood. (Time-resolved) electron paramagnetic resonance (EPR) spectroscopy is particularly suited to address these questions, allowing one to directly detect paramagnetic states and to reveal their spin-multiplicity, besides its clearly superior spectral resolution compared to optical methods. This article aims at giving a non-specialist audience an overview of what EPR spectroscopy and particularly its time-resolved variant (TREPR) can contribute to unraveling aspects of structure-function relationship in organic semiconductors.