Intermediate Band Material of Titanium-Doped Tin Disulfide for Wide Spectrum Solar Absorption

Group-IIIA element doped BaSnS2 as a high efficiency absorber for intermediate band solar cell from a first-principles insight

The quest for high-performance solar cell absorbers has garnered significant attention in the field of photovoltaic research in recent years. To overcome the Shockley-Queisser (SQ) limit of ∼31% for single junction solar cell and realize higher power conversion efficiency, the concept of an intermediate band solar cell (IBSC) has been proposed. This involves the incorporation of an intermediate band (IB) to assist the three band-edge absorptions within the single absorber layer. BaSnS2 has an appropriate width of its forbidden gap in order to host an IB. In this work, doping of BaSnS2 was studied based on hybrid functional calculations. The results demonstrated that isolated and half-filled IBs were generated with suitable energy states in the band gap region after group-IIIA element (i.e., Al, Ga, and In) doping at Sn site. The theoretical efficiencies under one sun illumination of 39.0%, 44.3%, and 39.7% were obtained for 25% doping concentration of Al, Ga, and In, respectively; thus, larger than the single-junction SQ-limit. Furthermore, the dopants have lower formation energies when substituting the Sn site compare to occupying the Ba and S sites, and that helps realizing a proper IB with three band-edge absorptions. Therefore, group-IIIA element doped BaSnS2 is proposed as a high-efficiency absorber for IBSC.

Transition Metal-Hyperdoped InP Semiconductors as Efficient Solar Absorber Materials

This work explores the possibility of increasing the photovoltaic efficiency of InP semiconductors through a hyperdoping process with transition metals (TM = Ti, V, Cr, Mn). To this end, we investigated the crystal structure, electronic band and optical absorption features of TM-hyperdoped InP (TM@InP), with the formula TMxIn1-xP (x = 0.03), by using accurate ab initio electronic structure calculations. The analysis of the electronic structure shows that TM 3d-orbitals induce new states in the host semiconductor bandgap, leading to improved absorption features that cover the whole range of the sunlight spectrum. The best results are obtained for Cr@InP, which is an excellent candidate as an in-gap band (IGB) absorber material. As a result, the sunlight absorption of the material is considerably improved through new sub-bandgap transitions across the IGB. Our results provide a systematic and overall perspective about the effects of transition metal hyperdoping into the exploitation of new semiconductors as potential key materials for photovoltaic applications.

Light trapping structures and plasmons synergistically enhance the photovoltaic performance of full-spectrum solar cells

A full-spectrum solar cell exhibits potential as an effective strategy to enhance the absorption of incident solar light. To ensure the absorption capability of solar cells, trapping structures or plasmons have emerged as two main ways of utilizing the full spectrum of solar energy. First, recent progress in the full-spectrum solar cells based on NCs was reviewed from the aspects of trapping structures and plasmon design. Moreover, the effects of light trapping and surface plasmon resonance on light absorption and photoelectronic conversion were emphasized and discussed. Finally, the application prospect of their combination in the field of full-spectrum solar cells was examined. It was pointed out that the deep exploration of the physical mechanism of photoelectric conversion, controllable preparation of the interface and stability of composite structures will become the main directions of future research.

Fundamentals and challenges of ultrathin 2D photocatalysts in boosting CO2 photoreduction

Ultrathin 2D materials serve as ideal models for tailoring three crucial parameters that determine CO₂ photoconversion efficiency and product selectivity.

Defect-induced abnormal enhanced upconversion luminescence in BiOBr:Yb3+/Er3+ ultrathin nanosheets and its influence on visible-NIR light photocatalysis

In oxygen vacancy-rich BiOBr:Yb³⁺/Er³⁺ ultrathin nanosheets, the oxygen vacancy induced intermediate band effectively enhances UC luminescence.

Effective Modulation of Optical and Photoelectrical Properties of SnS2 Hexagonal Nanoflakes via Zn Incorporation

Tin sulfides are promising materials in the fields of photoelectronics and photovoltaics because of their appropriate energy bands. However, doping in SnS₂ can improve the stability and robustness of this material in potential applications. Herein, we report the synthesis of SnS₂ nanoflakes with Zn doping via simple hydrothermal route. The effect of doping Zn was found to display a huge influence in the structural and crystalline order of as synthesized SnS₂. Their optical properties attest Zn doping of SnS₂ results in reduction of the band gap which benefits strong visible-light absorption. Significantly, enhanced photoresponse was observed with respect to pristine SnS₂. Such enhancement could result in improved electronic conductivity and sensitivity due to Zn doping at appropriate concentration. These excellent performances show that Sn_1−xZn_xS₂ nanoflakes could offer huge potential for nanoelectronics and optoelectronics device applications.

Solution-Processed Ultrathin SnS2-Pt Nanoplates for Photoelectrochemical Water Oxidation

Tin disulfide (SnS₂) is attracting significant interest because of the abundance of its elements and its excellent optoelectronic properties in part related to its layered structure. In this work, we specify the preparation of ultrathin SnS₂ nanoplates (NPLs) through a hot-injection solution-based process. Subsequently, Pt was grown on their surface via in situ reduction of a Pt salt. The photoelectrochemical (PEC) performance of such nanoheterostructures as photoanode toward water oxidation was tested afterwards. Optimized SnS₂-Pt photoanodes provided significantly higher photocurrent densities than bare SnS₂ and SnS₂-based photoanodes of previously reported study. Mott-Schottky analysis and PEC impedance spectroscopy (PEIS) were used to analyze in more detail the effect of Pt on the PEC performance. From these analyses, we attribute the enhanced activity of SnS₂-Pt photoanodes reported here to a combination of the very thin SnS₂ NPLs and the proper electronic contact between Pt nanoparticles (NPs) and SnS₂.