Conducting polymers (CPs), thanks to their unique properties, structures made on-demand, new composite mixtures, and possibility of deposit on a surface by chemical, physical, or electrochemical methodologies, have shown in the last years a renaissance and have been widely used in important fields of chemistry and materials science. Due to the extent of the literature on CPs, this review, after a concise introduction about the interrelationship between electrochemistry and conducting polymers, is focused exclusively on the following applications: energy (energy storage devices and solar cells), use in environmental remediation (anion and cation trapping, electrocatalytic reduction/oxidation of pollutants on CP based electrodes, and adsorption of pollutants) and finally electroanalysis as chemical sensors in solution, gas phase, and chiral molecules. This review is expected to be comprehensive, authoritative, and useful to the chemical community interested in CPs and their applications.

Hybrid halide perovskites that are currently intensively studied for photovoltaic applications, also present outstanding properties for light emission. Here, we report on the preparation of bright solid state light emitting diodes (LEDs) based on a solution-processed hybrid lead halide perovskite (Pe). In particular, we have utilized the perovskite generally described with the formula CH 3 NH 3 PbI 3-x Cl x and exploited a configuration without electron or hole blocking layer in addition to the injecting layers. Compact TiO 2 and Spiro-OMeTAD were used as electron and hole injecting layers, respectively. We have demonstrated a bright combined visible-infrared radiance of 7.1 W• sr −1 •m −2 at a current density of 232 mA•cm −2 , and a maximum external quantum efficiency (EQE) of 0.48%. The devices prepared surpass the EQE values achieved in previous reports, considering devices with just an injecting layer without any additional blocking layer. Significantly, the maximum EQE value of our devices is obtained at applied voltages as low as 2 V, with a turn-on voltage as low as the Pe band gap (V turn-on = 1.45 ± 0.06 V). This outstanding performance, despite the simplicity of the approach, highlights the enormous potentiality of Pe-LEDs. In addition, we present a stability study of unsealed Pe-LEDs, which demonstrates a dramatic influence of the measurement atmosphere on the performance of the devices. The decrease of the electroluminescence (EL) under continuous operation can be attributed to an increase of the nonradiative recombination pathways, rather than a degradation of the perovskite material itself.

Appropriate selection of electron buffer layer and understanding its impact on the photo‐generated charge transfer dynamics at the interfaces are critical to enhance the efficiency of solar cells. By optimizing a multilayer electron buffer composed of CdS thin film deposited on TiO2 compact layer, we obtained a power conversion efficiency (PCE) of 5.47% for a planar solar cell of Sb2(SxSe1‐x)3 absorber. The PCE was significantly enhanced in the photovoltaic parameters of planar solar cells fabricated with single‐layer configuration: for example, PCE of 3.99% and 0.79% were obtained when either CdS or TiO2, respectively, were used. Surface photovoltage spectroscopy, transient photovoltage, and electrochemical impedance spectroscopy analyses indicated that the PCE improvement can be ascribed to a combination of 2 factors: (i) better separation and transfer of the photo‐excited free charge, provided by the beneficial energy level alignment between TiO2 and CdS layers, and (ii) sulfur passivation upon incorporation of CdS in a multilayer configuration causing a reduction in the trap states at the interface with Sb2(SxSe1‐x)3.