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Due to the ease of synthesis and the ability to easily tune properties, organic semiconductors are widely researched and used in many optoelectronic applications. Requirements such as thermal stability, appropriate energy levels and charge carrier mobility have to be met in order to consider suitability of an organic semiconductor for specific application. Balancing of said properties is not a trivial task, often one characteristic is sacrificed to improve the other, therefore search for well-balanced materials is necessary. Herein seven new charge-transporting biphenyl-based enamine molecules are reported. The new materials were synthesized using a simple one-step reaction without the use of expensive transition metal catalysts. It was observed that subtle variations in the structure lead to notable changes in the properties. Materials exhibited high thermal stability and relatively high carrier drift mobility, reaching 2 × 10−2 cm2V−1 s−1 (for BE3) at strong electric fields. Based on the results, three materials show the potential to be applied in organic light emitting diodes and solar cells.

We report the synthesis of three novel enamine hole-transporting materials (HTMs) based on Tröger's base scaffold. These compounds are obtained in a three-step facile synthesis from commercially available materials, without the need of expensive catalysts, inert conditions or time consuming purification steps. The best performing material, HTM3, demonstrated 18.62 % PCE in PSCs, rivaling Spiro-OMeTAD in efficiency, and showing markedly superior long-term stability in non-encapsulated devices. In dopant-free PSCs HTM3 outperformed Spiro-OMeTAD by 1.6 times. The high glass transition temperature (Tg = 176 °C) of HTM3 also suggests promising perspectives in device applications. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The current state of the art in direct water splitting in photo-electrochemical cells (PECs) is presented together with: (i) a case study of water splitting using a simple solar cell with the most efficient water splitting electrodes and (ii) a detailed mechanism analysis. Detailed analysis of the energy balance and efficiency of solar hydrogen production are presented. The role of hydrogen peroxide formation as an intermediate in oxygen evolution reaction is newly revealed and explains why an oxygen evolution is not taking place at the thermodynamically expected 1.23 V potential. Solar hydrogen production with electrical-to-hydrogen conversion efficiency of 52% is demonstrated using a simple ~0.7%-efficient n-Si/Ni Schottky solar cell connected to a water electrolysis cell. This case study shows that separation of the processes of solar harvesting and electrolysis avoids photo-electrode corrosion and utilizes optimal electrodes for hydrogen and oxygen evolution reactions and achieves ~10% efficiency in light-to-hydrogen conversion with a standard 18% efficient household roof Si-solar cells.

The present invention relates to a compound of formula (I) based on carbazole substituted by diphenylamine and used as organic hole conductors or hole transporting material in a optoelectronic or photoelectrochemical device. (I), D being being selected from formula (1) or (2)

The present invention relates to a compound of formula (I) based on enamine derivatives and used as organic hole conductors or hole transporting material in an optoelectronic or photoelectrochemical device. The present invention relates to the hole transporting compounds based on enamine derivatives for efficiency perovskite or dye sensitized solar cells and optoelectronic devices, organic light-emitting diode (OLED), field-effect transistors (FET).

Small-molecule hole transporting materials based on methoxydiphenylamine-substituted fluorene fragments were synthesized and incorporated into a perovskite solar cell, which displayed a power conversion efficiency of up to 19.96%, one of the highest conversion efficiencies reported. The investigated hole transporting materials were synthesized in two steps from commercially available and relatively inexpensive starting reagents, resulting in up to fivefold cost reduction of the final product compared with spiro-OMeTAD. Electro-optical and thermoanalytical measurements such as UV/Vis, thin-film conductivity, hole mobility, DSC, TGA, ionization potential and current voltage scans of the full perovskite solar cells have been carried out to characterize the new materials.

Small-molecule hole transporting materials based on an indolocar-bazole core were synthesized and incorporated into perovskite solar cells, which displayed a power conversion efficiency up to 15.24%. The investigated hole transporting materials were synthesized in three steps from commercially available and relatively inexpensive starting materials without using expensive catalysts. Various electro-optical measurements (UV-vis, CV, hole mobility, DSC, TGA, ionization potential) have been carried out to characterize the new hole transporting materials.

The small-molecule-based hole-transporting material methoxydiphenylamine-substituted carbazole was synthesized and incorporated into a CH3NH3PbI3 perovskite solar cell, which displayed a power conversion efficiency of 16.91%, the second highest conversion efficiency after that of Spiro-OMeTAD. The investigated hole-transporting material was synthesized in two steps from commercially available and relatively inexpensive starting reagents. Various electro-optical measurements (UV/Vis, IV, thin-film conductivity, hole mobility, DSC, TGA, ionization potential) have been carried out to characterize the new hole-transporting material.

Remote epitaxy is a novel technique for crystal growth. It is based on remote interaction between the epitaxial layer and the substrate via the graphene interlayer. The van der Waals surface of graphene allows facile epilayer release while preserving the high quality of the epilayer and enabling the reuse of the substrate. This work aims to investigate the suitability of graphene-covered gallium nitride/sapphire template for the remote epitaxy of GaN by metalorganic vapor phase epitaxy process. Different graphene transfer techniques are examined. The influence of GaN film growth parameters on GaN quality is investigated. Finally, the exfoliation of the GaN membrane is demonstrated. This work should be valuable for further remote epitaxy technology development.