Robust singlet fission process in strong absorption π-expanded diketopyrrolopyrroles.

Singlet fission (SF) has drawn tremendous attention as a multiexciton generation process that could mitigate the thermal loss and boost the efficiency of solar energy conversion. Although a SF-based solar cell with an EQE above 100% has already been fabricated successfully, the practical efficiency of the corresponding devices is plagued by the limited scope of SF materials. Therefore, it is of great importance to design and develop new SF-capable compounds aiming at practical device application. In the current contribution, via a π-expanded strategy, we presented a new series of robust SF chromophores based on polycyclic DPP derivatives, Ex-DPPs. Compared to conventional DPP molecules, Ex-DPPs feature strong absorption with a fivefold extinction coefficient, good molecular rigidity to effectively restrain non-radiative deactivation, and an expanded π-skeleton which endow them with well-suited intermolecular packing geometries for achieving efficient SF process. These results not only provide a new type of high-efficiency SF chromophore but also address some basic guidelines for the design of potential SF materials targeting practical light harvesting applications.

Distinctive Excited State Symmetry Breaking Dynamics in Typical Donor-Acceptor-Donor Fluorophore: Strong Photoluminescence and Ultrafast Charge Separation from a Partial Charge Transfer State.

Understanding the structure-property relationships in organic semiconductors is crucial for controlling their photophysical properties and developing new optoelectronic materials. Quadrupolar molecules, donor-acceptor-donor (DAD), have attracted extensive attention in various optoelectronic applications. However, the systematic studies on the differences on photophysical properties between DAD and simple donor-acceptor (DA) chromophores are rarely reported. Herein we present a comparative study on the excited state dynamics of DA and DAD fluorescence systems using theoretical calculation and transient absorption spectroscopy. Results show that DA and DAD molecules exhibit similar excited state dynamics, which are attributed to the distinctive excited-state symmetry breaking (ESSB) phenomenon observed in a DAD system. The strong photoluminescence (PL) and ultrafast charge separation (CS) from an ESSB-induced partial charge transfer (CT) state were clearly detected in different solvent environments. These results not only offer insight into the excited state dynamics of the DAD fluorescence system but also provide some basic guidelines for designing new optoelectronic materials.

Preclinical detection of lysophosphatidic acid: A new window for ovarian cancer diagnostics.

Ovarian cancer, a highly metastatic disease characterized by widespread peritoneal and ascites dissemination, is the leading cause of death from gynecological malignancies and poses a serious threat to women's lives. Biomarkers detection for the early diagnosis is crucial to ameliorate the dismal survival rate. Currently, there is much interest in lysophosphatidic acid (LPA), with evidences shown that the elevated LPA level in plasma could serve as an effective biomarker for ovarian cancer. Thus the mastery of LPA measurement techniques is conducive to providing a new diagnostic or prognostic platform for ovarian cancer. In this tutorial review, with a brief discussion on the sample pre-treatment protocols, we summarize various methods for LPA detection with emphasis on the advances in universal mass spectrometry-based technologies and emerging optical sensor strategies. Meanwhile, other methods such as enzymatic method, capillary electrophoresis, dot immunogold filtration assay and bioassay are also included. Eventually, we outlook the potential clinical value of LPA detection, and anticipate the future improvements of these methodologies to make them truly useful for ovarian cancer diagnosis.