Pinhole Patching by Free Radicals for Highly Efficient Perovskite Solar Cells Fabricated in High-Moisture Environments

2-Hydroxy-2-methylpropiophenone (HMPP) and pentaerythritol triacrylate (PETA) are introduced into the perovskite layer via an antisolvent to enhance the photovoltaic performance of perovskite solar cells (PSCs) fabricated in a moisture atmosphere. Interestingly, the free radicals created from the decomposition of HMPP and PETA by irradiating UV light can effectively patch pinholes in the perovskite layer and regrow the crystal to enlarge the grain size. PETA can interact with Pb atoms via its lone pairs of electrons and forms a framework over the perovskite layer by in situ UV polymerization, resulting in a low trap-state density, high charge recombination resistance, long charge lifetime, and reduced hysteresis. Additionally, the PETA framework induces an enhanced driving force for charge separation at the heterojunction of the electron transport layer and the perovskite layer by adjusting the energy level of the perovskite. Consequently, a PSC with a silver top electrode can be fabricated under 70% RH conditions, exhibiting a high efficiency of 19.52% and good long-term stability. This enhancement surpassed most reported values in the literature for PSCs fabricated in a highly moist atmosphere

Fabrication of a Water-Stripped Free-Standing Silver Nanowire Network as the Top Electrode for Perovskite Solar Cells

Recently, there has been significant interest in inorganic–organic hybrid perovskite solar cells (PSCs) due to their excellent photovoltaic performance. However, the fabrication of PSCs’ top metallic electrodes using thermal evaporation in a vacuum atmosphere significantly increases the manufacturing cost and restricts large-scale production. In this study, we propose a water separation method for the fabrication of free-standing films of silver nanowires (AgNWs) that can be easily stripped by using water and laminated onto perovskite devices as top electrodes in an ambient atmosphere. The electrodes composed of long AgNWs exhibit superior electrical properties compared to those composed of shorter ones. We have identified that the reduced performance of PSCs with AgNW electrodes is mainly attributed to the high oxide content on the surface of AgNWs and the insufficient contact between the AgNW networks and hole transport layers. To resolve these issues, we employed sodium borohydride reduction and polyethoxysiloxane incorporation techniques. Through these treatments, PSCs with AgNW electrodes achieved a power conversion efficiency of 15.64%. This performance surpasses that reported in the literature for PSCs with AgNW electrodes, demonstrating the effectiveness of our approach

Fabrication of a Water-Stripped Free-Standing Silver Nanowire Network as the Top Electrode for Perovskite Solar Cells

Recently, there has been significant interest in inorganic–organic hybrid perovskite solar cells (PSCs) due to their excellent photovoltaic performance. However, the fabrication of PSCs’ top metallic electrodes using thermal evaporation in a vacuum atmosphere significantly increases the manufacturing cost and restricts large-scale production. In this study, we propose a water separation method for the fabrication of free-standing films of silver nanowires (AgNWs) that can be easily stripped by using water and laminated onto perovskite devices as top electrodes in an ambient atmosphere. The electrodes composed of long AgNWs exhibit superior electrical properties compared to those composed of shorter ones. We have identified that the reduced performance of PSCs with AgNW electrodes is mainly attributed to the high oxide content on the surface of AgNWs and the insufficient contact between the AgNW networks and hole transport layers. To resolve these issues, we employed sodium borohydride reduction and polyethoxysiloxane incorporation techniques. Through these treatments, PSCs with AgNW electrodes achieved a power conversion efficiency of 15.64%. This performance surpasses that reported in the literature for PSCs with AgNW electrodes, demonstrating the effectiveness of our approach

Hydrophilic Ligand Exchange Induces Improved Upconversion Nanoparticle Incorporation in Dye-Sensitized Solar Cells with Efficiency Exceeding 8% in a Low-Temperature Fabrication Process

We synthesized core–shell upconversion nanoparticles (UCNPs) with a composition of LiYF4:Yb0.2/Er0.02/Ho0.02/Tm0.02@LiYF4:Yb0.2 and incorporated them into the photoanodes of dye-sensitized solar cells (DSSCs) fabricated through a low-temperature process. The as-prepared hydrophobic UCNPs displayed a good protection ability to prevent the ingress of electrolyte but caused cracking in the mesoporous layers. To resolve this issue, we modified the as-prepared UCNPs by performing ligand exchange using 4-aminobenzoic acid (4ABA), transforming the hydrophobic surface into a hydrophilic one. By design of a three-layer structure to prevent electrolyte ingress, the hydrophilic nature of the 4ABA-modified UCNPs enabled better incorporation into the photoanodes. Consequently, the incorporation of 4ABA-UCNPs significantly improved the power conversion efficiency of DSSCs from 6.32 to 8.22%. This enhancement surpassed most reported values in the literature for DSSCs fabricated using a low-temperature process. Importantly, compared to other hydrophilic ligands, the use of 4ABA did not noticeably increase the charge transfer resistance due to its appropriate molecular weight

Synthesis of Dicarboxylic Acids Comprising an Ether Linkage and Cyclic Skeleton and Its Further Application for High-Performance Aluminum Electrolyte Capacitors

Aluminum electrolytic capacitors are essential components in all electronic devices, and it is known that their longevity depends on the performance of their electrolytes. We synthesized dicarboxylic acids having ether bonds showing the good solubility in ethylene glycol as a solvent and simultaneously developed a complete halogen removal method, which is strictly prohibited in capacitors. Moreover, the incorporation of bulky α-substituents and cyclic structures dramatically improved their heat resistance and can withstand high voltage, i.e., 764 V