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Cu 2 ZnSnS 4 (CZTS) solar cells occupy an important direction in the field of clean energy research due to their environmental friendliness, low cost, and industrial technology compatibility. The complex and variable usage environment also accelerates the development of flexible CZTS solar cells. However, the inferior flexibility of ITO films limited their development. ZnO/Ag/ZnO (ZAZ) films are potential choices for transparent conductive layers of CZTS solar cells due to their high transmittance, conductivity, and flexibility. To further enhance the photovoltaic performance and mechanical durability of ZAZ films and solar cells, Ag 2 O was introduced into ZAZ film by magnetron sputtering. An ultra-high average transmittance of 96.6% in 400–800 nm was achieved for ZnO/Ag-Ag 2 O/ZnO (ZAAZ) films at Ag 2 O sputtering power of 40 W, which was attributed to the fact that Ag 2 O effectively inhibited the growth of 3D islands of Ag film, and formed a more uniform Ag film. ZAAZ films offered a superior figure of merit value of 0.1041 Ω−1. The power conversion efficiency (PCE) of ZAAZ solar cells was 6.94%, higher than that of ZAZ solar cells (6.69%). Remarkably, the PCE of ZAAZ solar cells was 7.9% higher than that of ZAZ solar cells after 1000 bending cycles. Therefore, Therefore, this approach may provide a promising way to improve the photovoltaic performance and mechanical durability of flexible solar cells. • Ag 2 O was co-sputtered to increase Ag film continuity in ZnO/Ag/ZnO film. • A transmittance of 96.6% in ZnO/Ag-Ag 2 O/ZnO film was achieved by using Ag 2 O. • The ZAAZ film showed an ultra-low sheet resistance of 6.8 Ω·sq−1 at 40 W Ag 2 O power. • The power conversion efficiency of ZAAZ CSC was 0.25% higher than that of ZAZ CSC. • The Ag 2 O could also improve the mechanical durability of flexible ZAAZ CSC devices. [ABSTRACT FROM AUTHOR]

A series of Pr3+ doped SrWO 4 phosphors were synthesized using solid-state reaction routes. The phase composition, photoluminescence and temperature sensitivities of as-prepared materials were investigated. Rietveld refinement of measured XRD data was applied to analyze the lattice parameters. The optical transition was elaborated using UV–visible diffuse reflectance spectra and photoluminescence spectra. The photoluminescence measurements confirmed the strong visible light emission from the developed phosphors under both UV excitation at 250 nm and blue excitation at 450 nm. Notably, the maximum emission intensity was observed at a Pr3+ doping concentration of 2 mol%. Furthermore, the fluorescence intensity ratio (FIR) technique was employed, focusing on the emissions originating from the 3P 0 and 1D 2 state of Pr3+ within the temperature range of 298–598 K. Two FIR groups were adopted in this case, which can verify each other to achieve self-calibration. Typically, SrWO 4 :0.02Pr3+ exhibited remarkable performance as a temperature sensor, displaying an absolute sensitivity (Sa) of 3.11%K−1 and a relative sensitivity (Sr) of 0.81%K−1. As a result, the significant temperature-dependent PL and remarkable down-conversion luminescence make the SrWO 4 :Pr3+ material a promising candidate for optical thermometers and UV to visible converters of solar cell applications. • Intense visible emission of SrWO 4 :Pr3+ excited by 250 nm and 450 nm was observed. • FIR from non-thermally coupled energy levels was used for temperature sensing. • The wide-range and highly-sensitive of optical temperature sensing were realized. • The self-calibration of temperature measurement was achieved by two FIR groups. [ABSTRACT FROM AUTHOR]

Abstract Ultrathin c -Si solar cells with light trapping nanostructures attract tremendous research interest for their flexibility and high specific power density. However, the performance of the ultrathin c -Si solar cell is limited by a big light absorption loss due to the reduced thickness. Here, we report a novel ultrathin c -Si solar cell through the direct deposition of TiO 2 electron transporting layer and indium tin oxide (ITO) electrode modified with ultrathin low workfunction (WF) metal subsequently onto random inverted nanopyramids (INPs) texture. The random INPs are fabricated through the well-known two-step Ag assisted chemical etching method followed by a post nanostructure rebuilding process. The TiO 2 thickness, deposition temperature and metal layer thickness are changed to optimize cell performance. With the optimized parameters, a high short-current density (Jsc) (30.66 mA/cm2) and energy-conversion efficiency (11.36%) are achieved on random INPs based 45 μm ultrathin c -Si solar cell by choosing 2 nm Mg layer as the modifying ultrathin metal layer, which are 37.65% and 36.4% respectively higher than that in planar one. All the findings not only offer additional insight into the mechanism of TiO 2 electron transporting layer based ultrathin c -Si solar cell but also introduce a promising new approach for next-generation cost effective flexible photovoltaics. Graphical abstract Image 1 Highlights • TiO 2 electron transporting layer can separate carriers between c -Si and electrode. • Ultrathin metal with low work function is used to modify the work function of ITO. • Efficient light trapping on 45 μm c -Si is realized by inverted nanopyramids (INPs). • 11.36% efficiency is achieved on INPs based 45 μm c -Si cell by using ultrathin Mg. [ABSTRACT FROM AUTHOR]

Abstract It is considered that alkaline elements (such as Na, K, Rb) introduced through post-deposition treatment are able to modify the near-surface region of Cu(InGa)Se 2 thin films. However, research on the effects of Ca element on properties of Cu(InGa)Se 2 thin films is hardly reported. In this paper, Cu(InGa)Se 2 thin films were prepared on quartz glass by e-beam evaporation via two-step process. Study of structural property showed that a certain amount of CaF 2 through post-deposition treatment was beneficial to the uniform composition distribution of Cu(InGa)Se 2 thin films. Near-surface region of Cu(InGa)Se 2 thin films was more Cu-depleted by increasing introduced amount of Ca element. It was inferred that Ca diffused into the Cu(InGa)Se 2 thin films substituted the In sites as Ca In so as to increase the carrier concentration. By calculation, the spike barrier of CdS/Cu(InGa)Se 2 heterojunction was shown to decrease with increased thickness of CaF 2 layers. As a result, Cu(InGa)Se 2 solar cell subjected to 20 nm CaF 2 post-deposition treatment, which possessed higher fill factor, open circuit voltage and short circuit current density, achieved the optimal power conversion efficiency. An efficiency of Cu(InGa)Se 2 solar cell was enhanced by 2.9% after 20 nm CaF 2 post-deposition treatment. Highlights • Well crystallized CIGS thin films were prepared on quartz glass via two-step process. • Ga graded distribution in the films was alleviated after CaF 2 PDT. • Near-surface region of CIGS thin films was more Cu-poor by increasing amount of Ca. • An efficiency of CIGS solar cell was enhanced by 2.9% through 20 nm CaF 2 PDT. [ABSTRACT FROM AUTHOR]

Due to their excellent light absorption and photovoltaic effects, transition metal dichalcogenide-based heterojunctions have been widely investigated as materials for optoelectronic devices. This work presented a MoS 2 film preparation process using electron beam evaporated MoO 3 films as the precursor layer. The prepared MoS 2 film was used in the self-powered MoS 2 /Al 2 O 3 /n-Si photodetector, which showed high responsivity (1.15 A W−1), normalized detectivity (1.28 × 1011 Hz1/2 cm/W) and photoresponse (τ r = 28 μs) without external bias. Besides, the photodetector exhibited a large frequency-photoresponse range (up close to 100 kHz). Moreover, attributed to the excellent MoS 2 quality and the effective interface passivation by ALD-deposited Al 2 O 3 , the high-speed photoresponse of the photodetector was realized. These results demonstrated the potential of applying MoS 2 material prepared from electron beam evaporated MoO 3 precursor layers in the high-frequency and fast photoresponse photodetectors. • MoS 2 films were prepared by e-beam evaporation of MoO 3 films as precursor layers. • ALD-deposited Al 2 O 3 insertion layers were used to enhance device performance. • MoS 2 /Al 2 O 3 /n-Si PDs were made on Si substrate with an inverted pyramid structure. • The produced PDs showed a self-driven R of 1.15 A/W and a D* of 1.28 × 1011 Jones. • MoS 2 -based PDs depicted excellent stability for high pulses of light at 100 kHz. [ABSTRACT FROM AUTHOR]

• CuS films were prepared by e-beam evaporation of Cu films as precursor layers. • n-type Si wafers with inverted pyramid were used to enhanced device performance. • The CuS/n-Si PDs showed a self-driven R of 0.41 A/W and a rise time of 17 μs. • The CuS/n-Si heterojunction PDs demonstrated an EQE of 51.91% at 980 nm. Transition metal dichalcogenides (TMDCs) are considered to be the most promising next-generation materials for electronics and optoelectronics due to their excellent properties. In this work, well-performing CuS films were prepared by e-beam evaporation of Cu films as precursor layers. Ag/n-Si/Al 2 O 3 /CuS/ITO heterojunction photodetector with high responsivity (0.41 A·W−1), detectivity (1.739 × 1011 Jones) and fast response speed (17 μs) at zero bias were prepared by optimising sulphuration temperature and using silicon wafers with inverted pyramid light-trapping structures as substrates. Besides, the photodetector exhibited excellent light absorption ability, with an EQE of 51.91% at 980 nm. All these results demonstrated that excellent photodetector materials can be obtained by using metal films as precursor layers, which provides novel ideas and methods for the synthesis of TMDCs materials. [ABSTRACT FROM AUTHOR]

Abstract: The mechanical, thermo-physical properties and electronic band structures of SnS and SnSe have been calculated using density-functional theory (DFT). The elastic constants of SnS and SnSe obtained from calculations meet their mechanical stability conditions. The shear elastic properties of the {001} plane are both anisotropic for SnS and SnSe. Both compounds exhibit brittle behavior due to their low B/G ratio. The values of thermal capacity are close to 200J/molK at about 300K, and the thermal expansion coefficients decrease with increasing pressure at same temperature. The entropy is variable by power-exponent, and the internal energy is almost linear with increasing temperature for SnS and SnSe. The Gibbs energy of SnS is lower than that of SnSe under same temperature and pressure. Debye temperatures are 218K and 215K, and Grüneisen parameters are 3.25 and 2.98 for SnS and SnSe at 300K, respectively. Main anion (S, Se)p orbitals and a few cation (Sn)p and cation (Sn)s orbitals make the major contribution to the formation of the top of the valence band, and a broad structure as the conduction band, mainly due to both the cation (Sn)p and the anion (S, Se)p. [Copyright &y& Elsevier]

Abstract: La0.67Sr0.33MnO z (LSMO) thin films were prepared by means of metal–organic decomposition on amorphous quartz substrates under different annealing process. X-ray diffraction spectra show that proper crystallization temperature of the films is beyond 873K and all samples annealed at 953K or above present polycrystalline structure with [202] preferred orientation. Higher annealing temperature or longer annealing time lead to growth of larger grain. Regardless of the difference of grain size, all polycrystalline films present similar and steady magnetotransport properties, such as enhanced magnetoresistance (MR) effect below metal–insulator transition temperature and approximate MR ratio under same applied field, which were ascribed to the porous structural characteristics in the films observed by an atomic force microscope. Additionally, at room temperature the resistivity of each polycrystalline film presents linear change over wide range of applied field and get MR ratio near 5% under 10kOe field. [Copyright &y& Elsevier]

Micro and nano light-trapping structures are widely applied to improve the performance of optoelectronic devices. In this work, inverted-pyramid light trapping texture on industrial-sized p-type silicon was prepared by a rapid and repeatable one-step room-temperature Cu-MACE process. On this basis, various TMOs (transition metal oxide)-Si heterojunction photodetectors (PDs) are fabricated by a low-temperature process. After careful comparison, a ZnO/Al 2 O 3 /p-Si/Al 2 O 3 /CuO heterojunction is selected as the ideal device structure, and the corresponding work mechanism is proposed. Finally, by optimizing the Al 2 O 3 tunneling layers' thickness, a high-performance NIR PD working at 980 nm and −5 V bias stands out. The bifacial carrier selective transportation PD exhibits a considerable detectivity (5.56 × 1011 Jones) and a high responsivity (7.10 A/W). Our work will expand the application of inverted-pyramid textured silicon and will pave a road for mass fabrication of TMOs-Si heterojunction PD. • A new transition metal oxide-Si heterojunction photodetector was developed. • Photodetectors were produced on inverted-pyramid textured Si by Cu-MACE. • Improved device performance was achieved by ALD Al 2 O 3 tunneling layer. • High responsivity and good detectivity in the photodetectors were obtained. [ABSTRACT FROM AUTHOR]

In recent years, large and small industries have discharged a multitude of organic pollutants into the environment, causing environmental pollution. Titanium dioxide (TiO 2) materials is very important photocatalyst as a result of its outstanding applications to remove organic contaminants from the environment. Nonetheless, the low utilization rate of visible light of TiO 2 has limited its application. To begin with, Black TiO 2 is produced by the magnesium thermal reduction method to promote the absorption of visible light, Subsequently, The black TiO 2 /SnO 2 composites are synthesized by chemical synthesis method to form a hetero-junction to augment the photocatalytic activity. The morphology, chemical composition, phase structure and photocatalytic degradation of Rhodamine B (RhB) under visible light irradiation were investigated. The morphological properties demonstrated that a Ti3+ self-doped disorder layer forms on the surface of TiO 2 nanophase, and black TiO 2 nanoparticles are well decorated with SnO 2 nanoparticles. After 90 min of visible light irradiation, RhB has a photocatalytic degradation efficiency of 96.62%, which is 1.597 times that of TiO 2 nanoparticles, and its cycle stability is well beyond our expectation. The ameliorated photocatalytic degradation performance of TiO 2 /SnO 2 composite is ascribed to the formation of a "type Ⅱ heterojunction", which not only reinforces the absorption of visible light of black TiO 2 /SnO 2 nanoparticles, but also heightens the separation and transfer efficiency of the photogenerated carriers. • The black TiO 2 /SnO 2 composite are prepared to improve the photocatalytic activity. • The black TiO 2 are well decorated with SnO 2 nanoparticles to form "type Ⅱ heterojunction". • The composite exhibits an excellent visible-light photocatalytic performance and cycle stability. • The composite improve absorption of visible light and separation of the photogenerated carriers. [ABSTRACT FROM AUTHOR]