Digital printing of a novel electrode for stable flexible organic solar cells with a power conversion efficiency of 8.5

Advancing High-Performance Organic Solar Cells with Carbazole-Modified 2PACz for Scalable Large-Area Fabrication

The self-assembling molecule 2PACz tends to aggregate in thin films, which negatively impacts the performance of organic solar cells (OSCs) when used as a hole-transporting layer (HTL), particularly in large-area devices. To overcome this, a binary conjugated molecular system incorporating carbazole (Cz), which shares a similar backbone with 2PACz, is introduced. Despite the strong aggregation tendencies of 2PACz and Cz individually, their blend forms homogeneous films due to hydrogen bonding interactions between the two molecules. These interactions suppress 2PACz aggregation, resulting in smooth and well-ordered films. Devices with the modified HTL show significantly enhanced charge transfer, achieving a power conversion efficiency (PCE) of 20.10%, a fill factor of 80.3%, and a short-circuit current of 28.98 mA cm- 2, outperforming those with unmodified 2PACz. Large-area devices (1.0 cm2) with the modified HTL achieve a record-high PCE of 18.56% and a retention rate of 92.7%, compared to 43% for devices with 2PACz. These findings highlight the potential of carbazole-modified 2PACz to improve both efficiency and stability in OSCs, offering a promising strategy for high-performance HTL development.

Spin coated ultrathin PEDOT:PSS/SWCNT film with high electronic conductivity

Conductive Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been extensively used as non-metallic electrodes. However, the relatively low electrical conductivity of pristine PEDOT:PSS film restricts its further application. Although doping high content conductive filler or increasing the film thickness are effective for enhancing the electrical property, the transparency is sacrificed, which limits the application of PEDOT:PSS films. In this study, preparing PEDOT:PSS composite film with highly conductive and transparent property was the primary purpose. To achieve this goal, single-walled carbon nanotubes (SWCNTs) and dimethyl sulfoxide (DMSO) was chosen to composite with PEDOT:PSS. The spin-coated SWCNT/PEDOT:PSS composite film exhibited excellent electrical conductivity and transparency. The electrical conductivity of composite film with desired transmittance property (78%) reached the highest value (1060.96 S cm-1) at the SWCNTs content was 6 wt%. Under the modification process applied in this work, the non-conductive PSS was partially removed by incorporated DMSO and SWCNTs. Then, the molecular chains of PEDOT stretched and adsorbed onto the surface of SWCNTs, forming a highly efficient three-dimensional conductive structure, which contributed to the enhancement of electrical conductivity and transparency. Additionally, the spin-coating process allowed for the reduction of film thickness, ensuring better transparency. This research contributed to expanding the further applications of PEDOT:PSS films in high-performance transparent film electrodes.