Search

Current–voltage (IV) characterization is the most fundamental measurement performed on solar cells. This measurement is commonly used to extract basic solar cell parameters, such as open circuit voltage, short circuit current density, fill factor, and power conversion efficiency. We were able to obtain a fast tool to find defective behavior using Simulation Program with Integrated Circuit Emphasis simulations and generate an understanding of which device property can create such defective behaviors by analyzing the second derivative of IV curves. [ABSTRACT FROM AUTHOR]

Thermally induced degradation of organic photovoltaic devices hinders the commercialization of this emerging PV technology. Thus, a precise understanding of the origin of thermal device instability, as well as identifying strategies to circumvent degradation is of utmost importance. Here, it investigates thermally‐induced degradation of state‐of‐the‐art PBDB‐T‐2F (PM6):BTP (Y6) bulk heterojunction solar cells at different temperatures and reveal changes of their optical properties, photophysics, and morphology. The open‐circuit voltage and fill factor of thermally degraded devices are limited by dissociation and charge collection efficiency differences, while the short‐circuit current density is only slightly affected. Energy‐resolved electrochemical impedance spectroscopy measurements reveal that thermally degraded samples exhibit a higher energy barrier for the charge‐transfer state to charge‐separated state conversion. Furthermore, the field dependence of charge generation, recombination, and extraction are studied by time‐delayed collection field and transient photocurrent and photovoltage experiments, indicating significant bimolecular recombination limits device performance. Finally, coupled optical‐electrical device simulations are conducted to fit the devices' current‐voltage characteristics, enabling us to find useful correlations between optical and electrical properties of the active layers and device performance parameters. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) in an organic solar cell is one of the main components that play a crucial role in the extraction of charges, improving efficiency, and increasing the lifetime of the solar cells. Herein, solution‐processed PBDTTT‐C‐T:PC71BM‐based organic solar cells are fabricated using conjugated PDINO molecules, sol‐gel derived under stoichiometric titanium oxide (TiOx), and a mixture of the same as an ETL. For PBDTTT‐C‐T:PC71BM‐based organic solar cells, a blend of organic‐inorganic ETLs demonstrates reduced bimolecular recombination and trap‐assisted recombination than a single ETL of either two materials. Furthermore, in both, fullerene and nonfullerene systems, the efficiency of the devices employing the blend ETL as compared to the single ETLs show some performance improvement. The strategy of integrating compatible organic and inorganic interface materials to improve device efficiency and lifetime simultaneously, and demonstrate the universality of different systems, has potential significance for the commercial development of organic solar cells. [ABSTRACT FROM AUTHOR]

As the device performance and stability of polymer solar cells strongly depend on the interfacial charge extraction layers, the hole transport layer (HTL) properties are crucial. Furthermore, unfavorable interactions with the electrode or the photoactive layer should be screened and prevented. Organic solar cells of conventional architecture by varying the HTL material and layer stack systematically between PEDOT:PSS and a sol–gel‐derived tungsten oxide (WO3) are investigated. The impact of various HTLs in the solar cells is investigated by optical and electrical characterization. Interestingly, a triple‐layer WO3/PEDOT:PSS/WO3 configuration results in the best device performance specifically compared with the use of pristine WO3 and pristine PEDOT:PSS hole extraction layers. The triple layer also shows an increased reproducibility in the lifetime, which, combined with the improvement in the efficiency, can be the keys for expectable revenue. [ABSTRACT FROM AUTHOR]