Treating the Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Surface with Hydroquinone Enhances the Performance of Polymer Solar Cells

Enhanced Efficiency and Light Stability of Conventional Organic Solar Cells with a p-Type Polymeric Thin Layer on PEDOT:PSS

Simultaneous improvement in power conversion efficiency (PCE) and device stability is very important for organic solar cells (OSCs). Herein, oligothiophene-based polymer W19 with excellent solvent resistance is exploited as a polymer thin layer to optimize the active layer morphology and then device efficiency and stability. Polymer W19 possesses a simple skeleton of trifluromethyl-substituted dithienoquinoxaline and quaterthiophene, whose thin layer shows suitable energy level, low surface energy, and strong interchain aggregation, leading to outstanding solvent resistance and excellent hole transport ability. Optimized vertical separation alleviates trap state density and energy loss, improves hole transfer dynamics, and balances the charge transport, thus maximizing open-circuit voltage, short-circuit current density, and fill factor simultaneously. A high PCE of 19.70% is achieved for the W19 treated devices. Noticeably, OSCs treated with W19 retained 87% of its initial PCE after continuous illumination for 800 h, which is higher than that of 74% of the control. Large area devices of 1 and 4 cm2 can achieve high efficiencies of 17.36% and 14.46%, respectively. This work highlights that the polymer thin layer W19 with the ability of strong solvent resistance has the great potential to further improve the efficiency and photostability of OSCs.

Hydrogenation of Quinones to Hydroquinones under Atmospheric Pressure Catalyzed by a Metal-Ligand Bifunctional Iridium Catalyst

A general method for the hydrogenation of quinones to hydroquinones under atmospheric pressure has been developed. In the presence of [Cp*Ir(2,2'-bpyO)(H2O)] (0.5-1 mol %), a range of products were obtained in high yields. Furthemore, the expansion of this catalytic system to the hydrogenation of 1,4-benzoquinone diimines was also presented. Functional groups in the bpy ligand were found to be crucial for the catalytic activity of iridium complexes.

Synergistic Engineering of the Conductivity and Surface Properties of PEDOT:PSS-Based HTLs for Inverted Tin Perovskite Solar Cells to Achieve Efficiency over 10

A new simple environmentally benign water-soluble zwitterion, sulfamic acid (SA), was used as a multifunctional additive to tune the properties of PEDOT:PSS-based hole transporting layer (HTL). A layer of PEDOT:PSS was inserted in-between the ITO electrode and SA-modified PEDOT:PSS to form a pseudo bi-layered PS/SA@PS HTL to protect the ITO electrode from damage by more acidic SA@PS. Inverted tin-based perovskite solar cells based on the pseudo bi-layered PS/SA@PS HTLs achieved the highest efficiency of 10.5% with very small current hysteresis. The cell lost only 5% of the initial efficiency by storing in a glovebox without packing for more than 2000 h. The functions of SA include increasing the conductivity and mobility of the HTL to extract and transport the hole facilely by changing the conformation of PEDOT chains via zwitterion-induced charge screening, elevating the work function of PEDOT:PSS to match the VB of TPsk via increasing the PSS^- chains on the HTL surface, creating a more hydrophilic surface for depositing better quality tin perovskite film (TPsk with the chemical formula of FA_0.98EDA_0.01SnI₃), and avoiding the oxidation Sn²⁺ to Sn⁴⁺ via interacting with Sn²⁺ ions (at the HTL/absorber interface) using the sulfite group on SA, which were revealed with various physicochemical data.

Improving the Sensitivity of an Organic Photodetector by Adding a Polar Solvent to the Hole-Transport Layer for Indirect X-ray Detection

In this work, we investigated how the performance enhancement of an organic X-ray detector was improved by adding a dimethyl sulfoxide (DMSO) polar solvent to poly(3, 4-ethylene dioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) hole-transport layer. The changes in the properties, such as surface roughness, chemical structure, sheet resistance, and absorbance, of the PEDOT:PSS film caused by the DMSO treatment were examined. The application of DMSO treatment lowered the resistance of the PEDOT:PSS film because of the removal of PSS and the chemical structure change after DMSO treatment, and thus the transport of light-induced carriers was increased. The organic detector treated with 10 vol% DMSO showed the highest collected current density (CCD) of 357.42 nA/cm² and highest sensitivity of 2.58 mA/Gy ·cm², which were 31.88% and 32.31% higher than the CCD and sensitivity of the detector without DMSO treatment.

Hybrid Hole Extraction Layer Enabled High Efficiency in Polymer Solar Cells

Charge extraction layers with excellent charge extraction capability are essential for achieving high photovoltaic performance in cells. In this work, a hole extraction layer (HEL) is developed by doping conductive polymer TFB into CuSCN (CuSCN:TFB(X)), which exhibits good light transparency and high affinity for the light absorber. Compared to the reference cell, the CuSCN:TFB(X) HEL-based cells show impressive enhancement owing to the increased exciton dissociation and charge extraction processes and weak recombination losses. Furthermore, matched work function, better interface contact, and appropriate domain size also contribute to the enhanced power conversion efficiency. As a consequence, the highest conversion efficiency of 15.28% is observed in a cell based on the PM6:Y6 blend film and CuSCN:TFB(1.0%) HEL, which is >16% higher than the efficiency of 13.13% in a cell with CuSCN HEL.