Three cost-effective D-π-D hole transport materials (HTMs) with different π-bridge including biphenyl (SY1), phenanthrene (SY2) and pyrene (SY3) have been synthesized by one-pot reaction with cheap commercially available starting materials...

Harvesting hot carriers (HCs) before thermalizing to the perovskite crystal lattice is very promising for advancing the efficiency of perovskite solar cells (PSCs) towards the Shockley-Queisser limit. Thus, it is very crucial to slow down the HCs cooling process in lead halide perovskites. Herein, we investigated the HCs cooling dynamics of perovskite films in the presence of an organic small molecule, 2,5-thiophenedicarboxylic acid (TDCA). We found that adding TDCA into perovskite films can efficiently retard HCs cooling process, which favors extracting the excess energies of HCs through carrier transport layers and reducing electron-hole recombination, resulting in enhanced performance in TDCA modified device. Moreover, TDCA can effectively passivate unsaturated Pb 2+ defects of perovskite films while promoting a preferential crystal orientation. Consequently, the PSCs efficiency is enhanced to 22.85% (TDCA) from 19.96% (control). These findings provide important insight for understanding HCs transfer dynamics and developing nextgeneration perovskite-based HCs optoelectronic devices.

A novel modified glassy carbon electrode was prepared as an electrochemical voltammetric sensor based on molecularly imprinted polymer film for serotonin detection. The sensitive film was prepared by co-polymerization of 5-hydroxy tryptophan (5-HTP) and acrylamide (AM) on the carbon nanotubes modified glassy carbon electrode. The surface morphologies of the modified electrodes were characterized by scanning electron microscope. The electrochemical behavior of serotonin molecules on the imprinted electrode was studied by differential pulse voltammetry (DPV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimum conditions, the linear relationships between current and concentration were obtained in the range from 1.8 × 10 −6 to 5.4 × 10 −9 mol L −1 , with the linear regression equation Ip = 1.552 C + 8.778 × 10 −8 (I: μA, C: μmol L −1 ), correlation coefficient 0.9997. The detection limit of 1.8 × 10 −10 mol L −1 was achieved (S/N = 3). The applicability of the modified electrode was demonstrated by determination of serotonin in human serum. Moreover, the possible oxidation mechanism of 5-HT was discussed.

A large dimensional structured hole transporting material exhibits excellent photovoltaic performance in perovskite solar cells.