No abstract

Development of new n‐type semiconductors with tunable band gap and dielectric constant has significant implication in dissociating bound charge carrier relevant for demonstrating high performance optoelectronic devices. Boron‐β‐thioketonates (MTDKB), analogues to boron‐β‐diketonates containing a sulfur atom in the framework of β‐diketones were synthesized. Bulk transport measurement exhibited an outstanding bulk electron mobility of ≈0.003 cm2 V−1 s−1, which is among the best values reported till date in these class of semiconducting materials and correspondingly a single junction photo responsivity of upto 6 mA W−1 was obtained. This new family of O,S‐chelated boron compounds exhibited luminescence in the far red/near‐infrared region. The remarkable red shift of 89 nm (fluorescence) observed for 4 a in comparison with analogues boron‐β‐diketonate signifies the importance of sulfur in these molecules. MTDKBs with amine functionality have also been investigated as an ON/OFF fluorescent sensor.

Investigation of the mixed electronic and ionic charge transport in metal halide perovskite semiconductors has been challenging due to undesirable ion migration effects that accompany electronic charge transport. This results in unusual nonlinear hysteretic characteristics and significant degradation of the device performance. Here, we develop an understanding of the ionic and electronic transport using a combination of charge transport, impedance spectroscopy, and lateral conductivity measurement to illustrate the difference in the vertical and lateral ionic and electrical conductivity in these classes of perovskite materials. Our measurements indicate that, although the vertical electronic charge transport remains unaffected by B-site compositional variation, the lateral conductivity increases by at least one order of magnitude upon substitution of Sn. Furthermore, the incorporation of Sn decreases both the vertical and lateral ionic conductivity. The observed decrease in the ionic conduction is attributed to the inherent Sn vacancy, which compensates for the ionic defects through the creation of neutral defect complexes. Our results provide clear guidance for developing strategies to control the ionic conductivity without significantly affecting the electronic conductivity, which can lead to stable hysteresis-free highperformance optoelectronic devices.