A compact TiO(2) layer is crucial to achieve high-efficiency perovskite solar cells. In this study, we developed a facile, low-cost and efficient method to fabricate a pinhole-free and ultrathin blocking layer based on highly crystallized TiO(2) quantum dots (QDs) with an average diameter of 3.6 nm. The surface morphology of the blocking layer and the photoelectric performance of the perovskite solar cells were investigated by spin-coating with three different materials: colloidal TiO(2) QDs, titanium precursor solution, and aqueous TiCl(4). Among these three treatments, the perovskite solar cell based on the TiO(2) QD compact layer offered the highest power conversion efficiency (PCE) of 16.97% with a photocurrent density of 22.48 mA cm(-2), a photovoltage of 1.063 V and a fill factor of 0.71. The enhancement of PCE mainly stems from the small series resistance and the large shunt resistance of the TiO(2) QD layer.
The
wavelength-tunable interlayer exciton (IE) from layered semiconductor
materials has not been achieved. van der Waals heterobilayers constructed
using single-layer transition metal dichalcogenides can produce continuously
changed interlayer band gaps, which is a feasible approach to achieve
tunable IEs. In this work, we design a series of van der Waals heterostructures
composed of a WSe2 layer with a fixed band gap and another
WS2(1–x)Se2x
alloy layer with continuously changed band gaps. The existence
of IEs and tunable interlayer band gaps in these heterobilayers is
verified by steady-state photoluminescence experiments. By tuning
the composition of the WS2(1–x)Se2x
alloy layers, we realized a very
wide tunable band gap range of 1.97–1.40 eV with a wavelength-tunable
IE emission range of 1.52–1.40 eV from the heterobilayers.
The time-resolved photoluminescence experiments show the IE emission
lifetimes over nanoseconds.
Two-dimensional transition metal dichalcogenides are of particular interest in high-performance photothermal conversion, yet there remains a huge challenge in their practical application in smart textiles for healthcare, energy, and personal protection. Herein, we controllably prepared MoS 2 hollow nanospheres with a high photothermal conversion efficiency of 36% via a microemulsion-hydrothermal method, which was further applied to construct photothermal fibers for personal thermal management after a hot-blast dip-drying process. Because of the prominent photothermal effect, the temperature of the photothermal fibers sharply increases from the room temperature value of 25.0 to 55.5 °C in 60 s under near-infrared illumination with a power density of 500 W/cm 2 . Furthermore, the photothermal fiber pad demonstrated an obvious temperature enhancement of 38.0 °C from a skin temperature of 22.0 °C after it was irradiated by natural sunlight for 60 s. Significantly, the antibacterial elimination rates of the photothermal fibers for Escherichia coli and Staphylococcus aureus are ∼99.9 and ∼99.8%, respectively. This strategy affords an avenue toward the practical application of photothermal materials in smart fibers for personal thermoregulation.
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