No abstract

We demonstrate a waveguide exciton–polariton (WGEP) sub-microlaser from a built-in Fabry–Pérot (FP) cavity based on self-assembled organic nanowires (ONWs) of 1,4-chloride-2,5-di[4′-(methlthio)styryl-benzene (CDSB).

High-performance short-wave infrared (SWIR) photodetectors (PDs) possess great potential in health monitoring, remote control, telecommunication, and medical diagnostics. In comparison with inorganic PDs, organic PDs (OPDs) stand out as good candidates for next-generation photodetection devices because of their ease of processing, tunable optoelectronic properties, lightweight, easy portability, and low-manufacturing cost. Herein, we reported two conjugated polymers with ultranarrow band gaps (0.6 eV) for photoconductor-mode SWIR OPDs, which exhibited broad and excellent photoresponse across the visible and IR regions as long as 1450 nm. Specifically, one of the polymers possessing longer exciton lifetimes and favorable morphology and molecular orientation was further applied for flexible OPDs, demonstrating excellent performance with the responsivity (R) and external quantum efficiency as high as 0.96 A/W and 106% at 1122 nm, respectively, comparable to those of 2D nanomaterial-based IR PDs. In addition, an image sensor composed of 16 × 16 flexible OPDs was constructed, which can detect spatial light intensity distribution (1342 nm) clearly. This contribution shed light on designing excellent conjugated polymers for high-performance photoconductor-mode OPDs, which can be employed for SWIR light image sensors.

Y6 is a new type of non-fullerene acceptor, which has led to power conversion efficiencies of single-junction polymer solar cells over 17% when combined with a careful choice of polymeric donors. However, the excited state characteristics of Y6, which is closely correlated with its opto-electronic applications, are not clear yet. In this work, we studied the excited state properties of the Y6 solution and Y6 film, by using steady-state and time-resolved spectroscopies as well as time-dependent density functional theory (TD-DFT) calculations. UV-Vis absorption and fluorescence simulation, natural transition orbitals (NTOs) and hole-electron distribution analysis of Y6 solution were performed for understanding the excitation properties of Y6 by using TD-DFT calculations. The lifetimes of the lowest singlet excited state in Y6 solution and film were estimated to be 0.98 and 0.8 ns, respectively. Combining the exciton lifetime and photoluminescence (PL) quantum yield, the intrinsic radiative decay lifetimes of Y6 in the solution and film were estimated, which were 1.3 and 10.5 ns for the Y6 solution and film, respectively. Long exciton lifetime (~0.8 ns) and intrinsic radiative decay lifetime (~10.5 ns) of Y6 film enable Y6 to be a good acceptor material for the application of polymer solar cells.