Graphene-polymer nanocomposites for structural and functional applications

The pressure to move towards renewable energy has inspired researchers to look for ideas in photovoltaics that may lead to a major breakthrough. Recently the use of perovskites as a light harvester has lead to stunning progress. The power conversion efficiency of perovskite solar cells is now approaching parity (>22 %) with that of the established technology which took decades to reach this level of performance. The use of a hole transport material (HTM) remains indispensable in perovskite solar cells. Perovskites can conduct holes, but they are present at low levels, and for efficient charge extraction a HTM layer is a prerequisite. Herein we provide an overview of the diverse types of HTM available, from organic to inorganic, in the hope of encouraging further research and the optimization of these materials.

Hole‐Transport Materials for Perovskite Solar Cells

Synthesis and Applications

Graphene oxide powders with different oxidation degree, prepared by synthesis variations of the Hummers method

Solid-state electronics

Processible polyazomethines and polyketanils: From aerospace to light-emitting diodes and other advanced applications

Polymers with triphenylamine units: Photonic and electroactive materials

Perspectives of applied graphene: Polymer solar cells

A series of six conjugated aromatic polyazomethines has been obtained by high-temperature solution polycondensation of diformyltriphenylamine with different primary aromatic diamines. The structures of polymers are characterized by means FTIR, 1H NMR, and 13C NMR spectroscopy and elemental analysis; the results show an agreement with the proposed structure. Polyazomethines emitted blue or blue-green light. Relative PL intensity of the polymers investigated in chloroform solution was found about 0.30%, while for doped ones it was about 20% in relation to 9,10-diphenylanthracene. Additionally, the photoluminescence spectra of the polyazomethines in polymer blend with poly(methyl methacrylate) (PMMA) have also been described. The lowest optical band gap value at 2.41 eV was detected. Polymers were investigated also by cyclic voltametry and differential pulse voltammetry in dichloromethane. An influence of different types of dopants, i.e., methanesulfonic acid (MSA), camphorsulfonic acid (CSA), m-cresol (MC),...

Hole Transport Triphenylamine−Azomethine Conjugated System: Synthesis and Optical, Photoluminescence, and Electrochemical Properties

In this review paper we summarize recent research trends for polymer fuel cells (PEMFCs) that utilize various graphene materials described in articles published since 2007. We propose to analyze the influence of graphene in PEMFCs in three aspects: (i) as an electrode (anode or cathode), (ii) as an additive to polymer electrolyte and (iii) as a filler to bipolar plates along with some discussions on future research directions. In Section 2 of this review, we shortly present the fundamental processes of fuel cells along with important parameters such as hydrogen oxidation and oxygen reduction reactions, polarization losses, exchange current density, open circuit voltage and efficiency for fuel cells. Additionally, with curt description of various kinds of fuel cells and types of polymers applied in PEMFCs. Moreover, we discuss briefly different synthetic routes of graphene and describe selected graphene properties ( Section 3 ). In Section 4 , we analyze in detail the possibilities of applied graphene or its derivatives in various places in PEMFCs. Graphene applied to PEMFCs has a significant contribution on the increased electrical or ionic conductivity, better mechanical durability and corrosion resistance, and higher electrochemical surface area, depending on the fuel cell component that is modified. For instance, taking into consideration the function of graphene in polymer fuel cells and based on the current review, the highest value of maximum power density of 0.742 W cm −2 was found for PEMFC with graphene utilized as an anode support. The promising results open the way for the usage of graphene as a prospective material for application in fuel cells. However, the main difficulty of graphene application is the fact that this material has to be sufficiently separated by additional compounds to prevent restacking of graphene sheets.

Agnieszka Iwan

Papers

Processible polyazomethines and polyketanils: From aerospace to light-emitting diodes and other advanced applications

Polymers with triphenylamine units: Photonic and electroactive materials

Perspectives of applied graphene: Polymer solar cells

Hole Transport Triphenylamine−Azomethine Conjugated System: Synthesis and Optical, Photoluminescence, and Electrochemical Properties

Polymer fuel cell components modified by graphene: Electrodes, electrolytes and bipolar plates