Histidine-based hybrid perovskites as promising materials for wide wavelength photodetection

Abstract

Layered 2D hybrid organic-inorganic perovskites (2D-HOIPs) exhibit a distinctive array of properties, including remarkable structural flexibility, enhanced resistance to moisture, and optoelectronic characteristics valuable for practical applications. Consequently, these materials are now widely acknowledged as pivotal components in optical and optoelectronic technologies. However, a significant drawback of 2D-HOIPs is their wide band gaps that has hindered their widespread application in optoelectronic devices. In this work we address this limitation by offering a novel series of 2D mixed-halide tin-based HOIPs with general formula (L-HisH)2SnBrxI4−x (where L-His = L-histidine, x = 4, 3.37, 1.70, 0.56, 0.44, and 0) for which the band gap can reach record narrow values, which are not typical for 2D-HOIPs. These compounds can be easily obtained in wide compositional range by implementing halide substitution approach. Each hybrid perovskite features a chiral structure imparted by chiral L-histidinium(+) cations interleaved between corner-shared tin halide octahedra, organized into single-layer thin inorganic slabs. Crucially, these new materials provide a high degree of flexibility in tuning their band gaps throughout the entire visible light spectrum, encompassing a range between 1.82 and 3.05 eV. As a “proof-of-concept”, we created a prototype HOIPs photodetector in which this HOIP was used as an active layer. It is noteworthy that the band gap of pure iodide perovskite is surprisingly narrow for this class of materials. The production of semiconductor materials with a variable width of the optical bandgap is the key to more versatile and diverse applications of these materials in the active components of modern optoelectronic devices. For the obtained prototype, light detection is observed in the wide range covering UV, visible and near-IR regions, marking a record achievement for 2D-HOIPs. Beyond photodetectors, these new histidine-based perovskites hold promise for applications in various other optoelectronic devices, including solar cells, photodiodes, phototransistors, polarized light detectors, and more.