Key message
Dwarf interstock produced smaller tree size and a more uniform leaf area spatial distribution of vegetative short shoot. These improved light interception and increased light partitioning ...to fruiting shoot.
The agronomic efficiency of dwarf interstocks is controversial in China, where almost 90 % of apple orchards, including high-density orchards, currently use vigorous rootstock. We quantified the influence of dwarf interstock on canopy structure and light interception in two apple cultivars commonly grown on the Chinese Loess Plateau. ‘Fuji’ and ‘Gala’ apple trees were grafted onto two rootstock/interstock combinations:
M. micromalus
/
M. domestica
cv. ‘Qinguan’, a vigorous interstock and
M. micromalus
/M26, a dwarf interstock. Nineteen trees, grown with the spindle training system, were digitized and allometric relationships were determined for all shoot types before harvests in 2011 and 2012. Virtual three-dimensional canopies were reconstructed and light interception was evaluated. The spatial distribution of leaf area density of vegetative short shoot was more uniform on dwarf interstock compared to the vigorous interstock. These improvements led to higher light interception efficiency in dwarf interstock trees. There were fewer poorly illuminated within-tree zones and shoots on dwarf interstock than on vigorous interstock. The dwarf interstock trees showed a 25 % silhouette to total leaf area (STAR) increase for the whole tree and 21 and 17 % STAR increases for fruiting shoots and vegetative short shoots, respectively. ‘Fuji’ foliage was more clumped than ‘Gala’, leading to lower light interception. The results indicate that dwarf interstocks can effectively improve light interception efficiency.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Degradation of organic solar cells has always hindered the commercialization of organic solar cells (OSCs). In this paper, we fabricate OSCs with a power conversion efficiency (PCE) of 16.20%. The ...impact of different layers on degradation is studied for the first time by performing accelerated aging test on each layer. The device experiencing accelerated aging process on ITO/ZnO barely decays, indicating the electron transport layer (ETL) ZnO hardly affects the device degradation. The device experiencing accelerated aging process on ITO/ZnO/active layer and the and the device experiencing accelerated aging process on ITO/ZnO/active layer/MoO3 decay fast, manifesting the big impact of active layer and MoO3 on degradation. During the accelerated aging process, the morphology of the active layer changes, hindering light absorption and charge transport. Besides, the work function of hole transport layer (HTL) MoO3 becomes shallower after accelerated aging, making the hole extraction less efficient. Transient absorption spectroscopy (TAS) is recorded to investigate exciton physics change during the accelerated aging process, proving that inefficient charge transfer (CT) state excitons formation and separation account for the PCE decay. The mechanism of the degradation of OSCs is discussed, laying the foundation of their commercialization.
The impact of different layers on the degradation of organic solar cells is illustrated and the exciton physics during the aging process is probed, providing suggestions of the stable organic photovoltaic materials design. Display omitted
•The impact of different layers on degradation is studied firstly by performing accelerated aging test on each layer.•The morphology of the active layer and work function of the hole transport layer play an important role in the device decay.•Exciton generation and separation become less efficient after aging.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Though power conversion efficiencies of perovskite solar cells of over 21% have been reported, the degradation of the performance of these cells in the presence of moisture still inhibits the ...commercialization of these otherwise promising devices. Herein, we decided to utilize the moisture sensitivity of perovskite materials and fabricate a moisture detector based on high-quality CH 3 NH 3 PbI 3−x Cl x nanosheet arrays. The resulting devices present a high sensitivity towards humidity with device resistance significantly dropping from 1.28 × 10 8 Ω at 30% relative humidity (RH) to 7.39 × 10 4 Ω at 90% RH and a response even faster than that of the commercial psychrometer. This response was even steeper than those of commercial psychrometers. Moreover, our device showed good reversibility and impressive specificity. Thus, the humidity sensitivity of perovskites, while disadvantageous for solar cell applications, was found to be quite applicable in a new field.
•Recent advances in POFs for photocatalytic H2O2 production are summarized.•The effective strategies to improve H2O2 production are highlighted.•Elucidates photocatalytic H2O2 production efficiency ...and possible reaction mechanism.•The current challenges and future perspectives of photocatalytic H2O2 production in POFs is declared.
Hydrogen peroxide (H2O2) has been recognized as a rather important chemical with extensive applications in environmental protection, chemical synthesis, military manufacturing, etc. However, the mature industrial strategy (i.e., anthraquinone oxidation) for H2O2 production is featured with heavy pollution and high energy consumption. Photocatalytic technology has been regarded as a sustainable strategy to convert H2O and O2 into H2O2. Recently, porous organic framework materials (POFs) including metal-organic frameworks (MOFs), covalent organic frameworks (COFs), covalent triazine frameworks (CTFs), covalent heptazine frameworks (CHFs), and hydrogen-bonded organic frameworks (HOFs) have exhibited significant potential for green H2O2 photosynthesis by virtue of their diverse synthesis methods, enormous specific surface areas, flexible design, adjustable band structure, and photoelectric property. In this review, the recent advances in H2O2 photosynthesis based on POFs are comprehensively investigated. The modification strategies to improve H2O2 production and their photocatalytic mechanisms are systematically analyzed. The current challenges and future perspectives in this field are highlighted as well. This review aims to give a complete picture of the research effort made to provide a deep understanding of the structure-activity relationship of H2O2 photogeneration over POFs, thus inspiring some new ideas to tackle the challenges in this field, and finally stimulating the efficient development of organic semiconductors for sustainable photogeneration of H2O2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Optically rough and physically flat transparent conductive (OR-PF) substrates facilitate the performance improvement of optoelectronic devices and functional glasses via simultaneously enabling ...high-quality growth of functional layers and effective light management. This paper studies the effect of the interface morphology of the hole array pattern (HAP) and the pillar array pattern (PAP) on the far-field scattering properties of OR-PF substrates fabricated by spin-coating Al-doped ZnO (AZO) on nanoimprint-patterned glasses for improving the performance of superstrate-type thin-film solar cells. Theoretical calculation based on bidirectional scattering distribution function predicts that HAP with a period of 1.5 μm and a diameter of 1.3 μm HAP(P1.5D1.3) and the PAP(P1.0D0.5) interface morphology have a haze ratio in transmission (HT) of around 64% and a scatter angle of larger than 34°. The fabricated AZO/HAP(P1.5D1.3) and AZO/PAP(P1.0D0.5) show a flat surface with a σrms of less than 9 nm, a high visible light transmittance of over 86%, a sheet resistance of about 30 Ω/sq, and strong far-field scattering. In particular, AZO/PAP(P1.0D0.5) possesses an average HT of over 11% at the wavelength range of 600–850 nm and an angular intensity distribution of over 1.5% at an azimuthal angle of around 55°, indicating stronger far-field scattering than the conventional pyramid-textured B-doped ZnO (BZO/F). Compared to the flat substrate, AZO/PAP generates an implied J sc gain of 16.2% in a CH3NH3PbI3 photoactive layer with a thickness of 300 nm under normal incidence at the wavelength range of 550–800 nm. For 60° incidence, AZO/PAP(P1.0D0.5) enables an implied J sc gain of 2.3% with respect to BZO/F. As applied to the front electrode of CH3NH3PbI3 thin-film solar cells, compared to BZO/F, AZO/PAP(P1.0D0.5) would enable a gain of up to 16.7 and 11.2% in photoelectric conversion efficiency for the 0 and 60° incidence, respectively.
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IJS, KILJ, NUK, PNG, UL, UM
Though mixed cation hybrid organic–inorganic perovskite materials are of promise due to the high efficiency and long-term stability of the corresponding devices, a fundamental understanding on the ...function of the mixed cation system is still unclear. Herein, we systematically investigate the roles of the Cs cation and Cl anion in inverted structure perovskite solar cells based on Cs x FA 0.2 MA 0.8−x Pb(I 1−y Cl y ) 3 . For the role of Cs, we observe that an appropriate amount of Cs in the film could improve the crystal quality of the film and optimize the energy band alignment of the device, thus reducing non-radiative recombination and promoting the charge transport efficiently. The presence of Cl with a suitable concentration also possesses these functions. More importantly, the two limitations for the application of the devices, hysteresis and performance instability, could also be addressed to some extent. Thus a high power conversion efficiency of 20.31% has been realized and a universal method for constructing highly-efficient perovskite solar cells has been provided.
Recently, inorganic perovskite materials have been achieved with broad consideration in photovoltaic technology owing to their exceptional structural, electronic, and optical properties. This work ...comprehensively studied the impact of the biaxial compressive and tensile strain on the structural, electronic, and optical properties of the inorganic halide perovskites APbBr3 (A= Rb and Cs) using the first-principles density-functional theory (FP-DFT). This study also initiated to recognize the function of the A-cation on the structural, electronic, and optical properties of the inorganic perovskites. The electronic band structures show that RbPbBr3 and CsPbBr3 are semiconductor materials with a direct bandgap of 1.31 eV and 1.68 eV at the R-point. When considering the spin-orbital coupling (SOC) relativistic effect, the bandgap of the RbPbBr3 and CsPbBr3 perovskites is reduced to 0.282 and 0.478 eV, respectively. Moreover, the bandgap of all the structures shows a reducing trend when the compressive strain is applied and an increasing trend when the tensile strain is introduced. Optical properties like dielectric functions, absorption coefficient, and electron loss function show that these materials have good absorption ability in the visible region due to their band properties. It is found that the peaks of the dielectric constant of APbBr3 (A= Rb and Cs) shift to lower photon energy (redshift) when increasing compressive strain, and in contrast, they show higher photon energy shifting nature (blueshift) when enhancing tensile strain. Therefore, these properties make the APbBr3 (A= Rb and Cs) perovskites very appropriate to apply in light management of solar cells and energy storage devices.
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•The RbPbBr3 and CsPbBr3 compounds are all semiconductors with a direct bandgapof 1.31 eV and 1.68 eV, respectively.•The bandgap of RbPbBr3 and CsPbBr3 perovskites is reduced to 0.282 and 0.478 eV, respectively with SOC effect.•The bandgap of APbRb3 shows a decreasing trend when the compressive strain is applied.•The bandgap of APbBr3 exhibited an increasing trend with increasing tensile strain.•The biaxial strain in APbBr3 can significantly increase their absorbance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract Plasmonic laser has great potential to overcome the optical diffraction limit, playing a crucial role in advancing nanophotonics and nanoelectronics for on-chip integration. However, current ...plasmonic lasers face several challenges, such as the difficulty in controlling nanowire (NW) size, disordered arrangement, and complicated fabrication process. Herein, ultra-thin gain media for plasmonic lasers below the cutoff size of the photonic mode are prepared using the polydimethylsiloxane-assisted imprinting. This method enables precise control over the size of the perovskite NW, with the minimum size achievable being 60 nm. As a result, the plasmonic lasing is achieved from the CsPbBr 3 NW-based device with a threshold as low as ∼49.13 μ J cm −2 and a Quality Factor ( Q ) of 1803 at room temperature, demonstrating its capability for achieving high-quality lasing. Meanwhile, a dual-pumping time-resolved fluorescence study suggests that the radiative recombination lifetime of CsPbBr 3 NWs is shortened by a factor of 10 due to the Purcell effect, confirming the plasmonic effect exhibited by the device. Furthermore, a plasmonic laser array is developed using this method, demonstrating the applicability of the imprinting method in complex graphic fabrication. This breakthrough provides a solution for the application of plasmonic laser arrays in optoelectronic integration.
This work demonstrates a nanoscale zirconia layer coated by atomic layer deposition (ALD) with only a few coating cycles on a nano-porous platinum cathode surface to serve as a physical confinement ...to prevent the electrode agglomeration under high temperature operation, and at the same time to enhance the cathode oxygen reduction activity. The resulted enhancement in cathode electrochemical performance can arise from the discontinuous ZrO2 film that facilitates the oxygen adsorption on cathode surface and decreases the oxygen adsorption–desorption resistance.
•Nanoscale ZrO2 were deposited on nano-porous Pt by atomic layer deposition (ALD).•10 ALD-cycles of ZrO2 (~1.6nm) effectively confined the thermally-driven agglomeration of Pt cathode.•The ZrO2 capping has also unexpectedly lowered the polarization resistance of Pt cathode.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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