To broaden the light-harvesting spectrum of perovskite solar cells (PSCs), WO3-X @CdS heterojunctions have been synthesized by in situ growing CdS nanoparticles on WO3-X nanorods rich in oxygen vacancies. After introducing them into perovskite layers by the antisolvent method, the localized surface plasmon resonance (LSPR) effect of WO3-X@CdS extends photon absorption into the near-infrared region, while both lattice match and its coordination with iodide ions facilitate uniform nucleation and crystallization process to obtain high-quality perovskite films. Moreover, this dual-functional material simultaneously optimizes the hole transport layer/perovskite energy alignment and accelerates the interfacial charge transfer via LSPR-induced near-field enhancement effects. The spectral expansion and improved carrier dynamics synergistically boost the power conversion efficiency to 25.08%, demonstrating heterojunction engineering as a viable strategy for advancing broadband PSCs and other optoelectronic devices.

Although many protocols have been developed to enhance the ionic conductivity and lithium-ion transference numbers of the solid polymer electrolyte, it is still challenging to improve them simultaneously. Herein, we design and prepare boron-doped graphene (BG) as an anion trapper and blend it within a poly(ethylene oxide) (PEO)-based electrolyte. The well-dispersed BG sheets can reduce the crystallinity of PEO and afford numerous Lewis acid sites to effectively accelerate the dissociation of the lithium salt and trap the anions. Thus, the PEO-based electrolytes containing BG sheets exhibit a high ionic conductivity of 9.27 × 10-5 S cm-1 and lithium-ion transference number of 0.57 at 25 °C, which ensure the stable Li stripping/plating over 1000 h. The all-solid-state lithium-ion batteries assembled with the as-prepared electrolyte show excellent rate performance and cycling stability at 25 °C.

Upconversion core-shell nanoparticles (NPs) exhibit great potential in enhancing the incident light utilization and power conversion efficiency (PCE) of perovskite solar cells (PSCs). Herein, a straightforward and universal dual-modulation strategy is proposed, which utilizes NaYF4:Yb,Tm@NaYF4 (NYF:Y,T@NYF) core-shell NPs to jointly modulate perovskite and hole transport layer for efficient optoelectronic management of n-i-p planar PSCs. The specific roles of NYF:Y,T@NYF NPs located in different parts in improving interface band alignment, photogenerated charge extraction/transfer/collection efficiency, device photocurrent, and photovoltaic (PV) parameters, etc. are clarified. Unique insights for promoting the crystallization and grain growth of the modulated perovskite are proposed. Thanks to the positive contribution of NYF:Y,T@NYF, the PCE of the champion PSC is considerably increased from 22.25% (control device) to 25.49%, with an open-circuit voltage of 1.20 V, a short-circuit current density of 26.74 mA cm-2, and a fill factor of 79.57%. Moreover, unencapsulated devices exhibit good long-term and operational stability. This work establishes a new model for strengthening the optoelectronic management of solar cells, and the proposed low-temperature, low-cost antisolvent reprocessing technology provides reliable guidance for the development of more efficient and durable perovskite-based PV devices.

In this work, a PEDOT:PSS/Sn:alpha-Ga2O3 hybrid heterojunction diode (HJD) photodetector was fabricated by spin-coating highly conductive PEDOT:PSS aqueous solution on the mist chemical vapor deposition (Mist-CVD) grown Sn:alpha-Ga2O3 film. This approach provides a facile and low-cost p-PEDOT:PSS/n-Sn:alpha-Ga2O3 spin-coating method that facilitates self-powering performance through p-n junction formation. A typical type-I heterojunction is formed at the interface of Sn:alpha-Ga2O3 film and PEDOT:PSS, and contributes to a significant photovoltaic effect with an open-circuit voltage (V-oc) of 0.4 V under the 254 nm ultraviolet (UV) light. When operating in self-powered mode, the HJD exhibits excellent photo-response performance including an outstanding photo-current of 10.9 nA, a rapid rise/decay time of 0.38/0.28 s, and a large on/off ratio of 91.2. Additionally, the HJD also possesses excellent photo-detection performance with a high responsivity of 5.61 mA/W and a good detectivity of 1.15 x 10(11) Jones at 0 V bias under 254 nm UV light illumination. Overall, this work may explore the potential range of self-powered and high-performance UV photodetectors.

Solar thermal power generation has been widely employed as an effective method for efficiently harnessing solar energy, with solid heat-collecting particles serving as the medium for collecting and storing solar energy, thus holding significant developmental potential. However, challenges such as high thermal radiation losses and inadequate high-temperature stability have hindered the further advancement of solid heat-collecting particles. The present study addresses these challenges by utilizing solid waste fly ash to prepare solar-selective absorbing solid heat-collecting particles. Specifically, particles sintered at 1070degree celsius exhibit impressive characteristics, including an average solar absorptance of 93.26 % at room temperature, an emissivity in the mid-infrared range of 68.12 %, and a specific heat capacity of 0.82 J/(g & sdot;degree celsius). Moreover, rigorous high-temperature stability tests demonstrate that these particles maintain a stable solar absorptance in the ultraviolet-visible-near-infrared range, consistently around 93.26 %. Additionally, the particles exhibit outstanding wear resistance and stability, further enhancing their suitability for practical applications. This research achieves the dual objectives of environmental sustainability and cost reduction by utilizing solid waste materials, while the preparation process remains simple, bolstering the feasibility of implementing these findings in real-world scenarios. In summary, this study effectively addresses the challenges of high thermal radiation losses and poor high-temperature stability in solid heat-collecting particles for solar thermal power generation.

Concentrated solar power (CSP) is a green energy technology that efficiently harnesses solar energy. Solid particles constitute the key medium for solar photothermal conversion and storage. However, drawbacks such as high thermal radiation loss and poor high -temperature stability limit their application. This paper proposes solid particles based on steel slag for highly efficient and durable selective sunlight absorptance and thermal storage. Raw pellets are obtained via a simple extrusion and rolling process, and sinter them to derive solid particles. These particles exhibit excellent selective solar absorption characteristics and have good potential for efficient heat storage. The average solar absorption of the solid particles sintered at 1310 degrees C reaches 93.20%, and the emissivity at 700 degrees C is 80.25%. Furthermore, the specific heat and the thermal conductivity of wafer-like materials are 1.09 J/(g & sdot; K) and 2.92 W/(m & sdot; K), respectively. In addition, the solid particles are arranged for exhaustive and harsh high -temperature durability tests, and they exhibit an ultra -stable solar weighted absorptance of 93.25 +/- 0.09% (mean +/- standard deviation), excellent resistance to thermal shock, and superior abrasion resistance. Moreover, the low cost and simplicity of the process greatly enhance the scalability of steelslag -based solid particles. In summary, by innovatively addressing the challenges faced by solid particles, such as high radiative heat loss, poor heat storage capacity, and high -temperature instability, this study accumulates an advantage in the competition with phase -change and thermochemical materials, and greatly improves the feasibility of using solid particles in large-scale applications.

Daytime radiative cooling offers a novel solution to the energy crisis, enabling green and efficient thermal management in space. High reflectance in the solar spectrum is essential for passive radiative cooling, rendering dye coloring and similar methods unsuitable for colored coolers. This paper presents a structurally colored photonic crystal biomimetic microstructured radiative cooler. Inspired by natural biological systems, this cooler features a dual-layered microtruncated-cone array structure on the surface and bottom membrane layers. The silver reflector and 3D micrograting surface structure produce continuous iridescent colors through multiple interference effects. Optimized lithographic process enable the fabrication of the ordered dual-layer surface microstructure arrays with precise angular combinations. The dual-layered microtruncated-cone introduces a gradient refractive index, reducing impedance mismatch at the interface. As a result, the radiative cooler achieves high solar spectral reflectance (0.95) and high mid-infrared emissivity (0.95). Notably, the net theoretical cooling power and the subambient temperature drop are 106.9 W m-2 and 7.4 degrees C, respectively, at an ambient temperature of 40 degrees C, with a measured average temperature reduction of 6.1 degrees C under direct sunlight. This performance matches that of advanced radiative coolers, striking a balance between aesthetics and radiative cooling capability.

As a promising ultra-wide bandgap semiconductor material, gallium oxide (Ga 2 O 3 ) is attracting extensive attention of researchers due to its feasible growth process, appropriate bandgap of 4.4 eV–5.3 eV allowing for deep-ultraviolet (deep-UV) detection, good physical and chemical stability, high breakdown field strength and electron mobility, etc. Different from the strict processes for controllable crystalline Ga 2 O 3 (usually refer to as stable monoclinic β -Ga 2 O 3 ), amorphous Ga 2 O 3 (a-Ga 2 O 3 ) film can be prepared uniformly at low temperature on a large-area deposition substrate, suggesting great advantages such as low manufacturing cost and excellent flexibility, dispensing with high-temperature and high vacuum techniques. Thus, a-Ga 2 O 3 extremely facilitates important applications in various applied fields. Therefore, in this concise review, we summarize several major deposition methods for a-Ga 2 O 3 films, of which the characteristics are discussed. Additionally, potential methods to optimize the film properties are proposed by right of the inspiration from some recent studies. Subsequently, the applications of a-Ga 2 O 3 thin films, e.g., in photodetectors, resistive random access memories (RRAMs) and gas sensors, are represented with a fruitful discussion of their structures and operating mechanisms.

A solar energy receiver is a device that absorbs solar radiation and transfers the generated heat energy to a heat transfer medium. As a heat transfer medium in solar energy receivers, solid particles can safely absorb strong solar radiation flux and achieve a higher operating temperature. Hence, they have attracted considerable research interest. The emissivity of particles is an important parameter in numerical simulation and efficiency analysis of solid particle receivers. However, it is rarely reported, especially for dispersed particles flowing in receivers. In this study, a measurement system for the normal spectral emissivity of free-falling particles is designed and developed. The system is based on the energy method and uses an FTIR spectrometer as a radiation measurement device, which can achieve measurement in the wavelength range of 2.5-16 mu m below 800 degrees C. The emissivity of the sheet SiC material is measured to verify the reliability of the system. The results are in good agreement with the data published in NIST. Furthermore, the effects of the particle material, temperature, and particle group thickness on the particle group emissivity are studied. It is found that the emissivity of gray ceramic sand particles is not sensitive to the temperature, whereas that of alumina ceramic particles is positively correlated with the temperature. The emissivity of the two particles increases rapidly with the release width of the particle group, which is related to the increase in the mass flow rate of the particle group. Finally, uncertainty analysis of the measurement system is performed. The results measured in this paper can provide the original emissivity data for heat transfer simulation and efficiency evaluation in the receiver.(c) 2023 Elsevier Ltd. All rights reserved.

Owing to the high bandgap of up to 4.8 eV, Ga2O3 has a natural advantage in the field of deep-ultraviolet (DUV) detection. The Ga2O3-based photoconductors, Schottky and heterojunction detectors are proposed and show excellent photodetection performance. The Ga2O3 heterojunction detectors are self-driven and feature low power consumption. On the other hand, considering the ultra-wide bandgap and low intrinsic carrier concentration, Ga2O3-based photodetectors are exhibiting important applications in high-temperature photodetection. In this work, a WO3/β-Ga2O3 heterojunction DUV photodetector is constructed and the effect of high temperature on its detection performance is investigated. The β-Ga2O3 films are prepared by metal-organic chemical vapor deposition (MOCVD), and WO3 films and Ti/Au ohmic electrodes are prepared by spin-coating technology and magnetron sputtering technique, respectively. The current-voltage (I-V) and current-time (I-t) measurements are performed at different ambient temperatures. Parameters including light-dark-current ratio (PDCR), responsivity (R), detectivity (D*), and external quantum efficiency (EQE) are extracted to evaluate the deep-ultraviolet detection performance and its high-temperature stability. At room temperature (300 K), the PDCR, the R, the D*, and the EQE of the detector are 3.05×106, 2.7 mA/W, 1.51×1013 Jones, and 1.32%, respectively. As the temperature increases, the dark current of the device increases and the photocurrent decreases, resulting in the degradation of the photodetection performance. To explore the physical mechanism behind the degradation of the detection performance, the effect of temperature on the carrier generation-combination process is investigated. It is found that the Shockley-Read-Hall (SRH) generation-combination mechanism is enhanced with the increase of temperature. Recombination centers are introduced from the crystal defects and interfacial defects, which originate mainly from the SRH process. Specifically, the dark current comes mainly from the depletion region of WO3/β-Ga2O3, and the carrier generation rate in the depletion region is enhanced with temperature increasing, which leads to the rise of dark current. Similarly, the increase of temperature leads to the improvement of the recombination process, therefore the photocurrent decreases at a higher temperature. This effect can also well explain the variation of response time at a high temperature. Overall, it is exhibited that the WO3/β-Ga2O3 heterojunction photodetector can achieve stable self-powered operation even at an ambient temperature of 450 K, indicating that the all-oxide heterojunction detector has potential applications in harsh detection environments.

Ultrawide bandgap semiconductor gallium oxide (Ga2O3) demonstrates a considerable advantage in detecting deep-ultraviolet (DUV) light signals in extreme environments. Relevant studies have shown that the Ga2O3 DUV photodetector (PD) is a promising candidate for high-temperature applications; however, its temperature-influenced photodetection performance has yet to be investigated. In this work, a Ga2O3 metal–semiconductor–metal (MSM) DUV PD was fabricated, and its temperature-dependent photodetection performance was studied. Decent detection metrics, including a photo-to-dark current ratio (PDCR) of $1.1\times 10^{{6}}$ , a responsivity ( ${R}$ ) of 45.83 mA/W, a specific detectivity ( ${D}^{\ast }$ ) of $3.4\times 10^{{13}}$ Jones, and an external quantum efficiency (EQE) of 22.4%, were achieved but decreased with increasing temperature. The increased operation temperature led to an increase in the dark current and a decrease in the photocurrent. In addition, the impact of high temperature on the photocurrent gain mechanism was examined in detail based on carrier recombination and transport processes. In general, impressive robustness of the Ga2O3 MSM DUV PD was achieved, further stressing the detection capability of Ga2O3 DUV PDs in harsh environments.

基于"光伏原理"课程,构建了太阳能光—热—电综合利用虚拟仿真实验系统,将其用于学生在线自学.通过开展线上线下混合式教学、翻转课堂等学习,教学实践取得了良好的效果.结果表明,基于虚拟仿真的线上线下混合课程构建对人才培养具有很好的促进作用.

Photovoltaic thermoelectric (PV-TE) coupling is an effective way to improve , expand solar energy utilization. The full spectral utilization of sunlight by a solar cell can be realized if the photonic active material absorbs light with the energy below its bandgap while the thermoelectric component absorbs the rest. This paper demonstrates the preparation of an ultra-broadband photon management structure for crystalline silicon cells for incorporation into PV-TE systems. This structure consisting of different nanostructures combined with thin-film layers is capable of reducing the device reflectivity and, thus, improving solar energy utilization.

《工程热力学》教材的编写与使用一直是国内外各高校非常关注的问题.中外高校所使用的教材有着明显的区别,教学方法和教学大纲也相差较大.通过对中美使用的《工程热力学》主流教材和教学大纲的总结,对比分析了教学形式、讲解顺序、例题搭配和紧跟科技前沿等方面的差异.国内外工程热力学的教学理念和体系,除了有明显差异外,也有共同点,如均注重培养学生实践动手能力和分析解决问题的能力.秉承求同存异的原则,提出了一些看法和观点,希望能够对国内《工程热力学》教材的编写和教学提供一定的帮助与借鉴.

It has a very broad prospect to use solid particles as the working medium in the solar collector of concentrated solar power generation system. The emissivity of a particle has an undeniable effect on the efficiency of a solid particle receiver. However, the spectral emissivity of a single particle at high temperature is rarely reported. In this work, an experimental method for measuring the spectral emissivity of a single particle at high temperature is established. This method is based on a self-designed heater, Fourier transform infrared spectrometer (FTIR) and a blackbody furnace. It can measure the spectral emissivity of a single particle at high-temperature of 500-900 degrees C, and the test wavelength range is 2.5-25 pm. By measuring the spectral emissivity of 3-5 mm diameter particles, the influence of particle size on the emissivity was obtained. The expanded uncertainty of spectral emissivity of 3 mm SiC particles at 800 degrees C is 1.380%.

Ca-Looping concentrated solar power with direct radiation absorption mode is promising, provided that the low light absorption of CaCO3/CaO can be solved. In this work, Ca-based thermochemical materials (CTMs) doped with Fe and Mn elements were synthesized by the sol-gel method. The added Fe and Mn elements increase the absorption of CTMs, while also effectively improving cyclic stability. Calcination experiments show that Ca0.15Fe2.85O4 can be used as additional materials to improve the absorption of CaCO3/CaO, and in particular, the near IR region. Additional findings suggest that morphology and cyclic stability of the materials are closely related. The porosity and pore size of CaCO3/CaO was also controlled by adjusting the amount of citric acid used during processing.

In recent years, CaO/CaCO3 has attracted great attention in the field of thermochemical energy storage. However, due to its very low optical absorption, thermochemical energy storage materials made of pure CaO/CaCO3 struggle to reach reaction temperatures when only absorbing solar energy directly in a calciner, making the overall system inefficient. Therefore, in this paper, calcium-based materials with both high optical absorption and high energy release density were synthesized to directly convert solar energy to chemical energy for storage. Doping metal elements into a Ca-based material was demonstrated to play a positive role in improving cycling stability on the energy release process. Here, we developed a loose and porous Ca-based composite consisting of two phases including CaCO3 and Ca2FeMnO5, exhibiting excellent cycling stability and high energy release density. The highest energy release density after 20 cycles reached 2.51 MJ/kg, which is 2.62 times that of pure CaCO3. Meanwhile, the highest optical absorption reached 76.8%, which is 7.11 times that of pure CaCO3. The Ca-based materials developed in this paper can improve cycling stability and enhanced optical absorption simultaneously, providing guidance for the efficient development of calcium looping thermochemical energy storage systems in the future.

工程热力学基础是一门能源动力类、航空航天类、机械类等相关专业的重要专业基础课,课程中的能量守恒定律、熵、炯等热力学概念和原理是能源高效利用重要的理论基础.在本课程的教学过程中,将多种能源梯级利用,提高能量释放品位和效率,实现能源的高效利用.

The photovoltaic-thermoelectric (PV-TE) hybrid system can achieve full-spectrum utilization of the solar spectrum, but surface reflection has always been an important reason to suppress its power conversion efficiency. Therefore, a novel composite nanostructure (CN) is proposed by the finite-difference time-domain (FDTD) simulation method to reduce the surface reflection in the spectral range of 03-2.5 pm, which consists of a pyramid and grating structure. For the sake of generality, this paper studies the spectral reflectance of the CN under multiple parameters. The results show that the CN integrated pyramid and grating correspond to excellent anti-reflection performance in the short wavelength range and long wavelength range, respectively, compared to a unitary structure, achieving anti-reflection in the full spectral range. In addition, the CN expresses the insensitivity to the structural parameters, and has lower reflectivity compared with a commercial battery. The mechanism for achieving this full-spectrum anti-reflection is mainly to enhance the path of light in the medium to enhance absorption and achieve high transmission under the action of the waveguide. This paper implements ultra-broadband anti-reflection of a compound nanostructure for full-spectrum utilization of solar energy, and provides a solution to improve the power conversion efficiency of PV-TE hybrid systems. (C) 2019 Optical Society of America

Material properties and surface morphology of nanostructures have impact on optical characteristics of nanostructures. More and more arrays of nanostructures are investigated to regulate and control surface radiation characteristics. However, the majority of the object surfaces are random rough surfaces in daily life, the radiation characteristics of which are widely used in various fields including remote sensing, photovoltaic utilization and thermal control. Therefore, the radiation characteristics of random rough surfaces are important for both academic research and practical applications. In this paper, a recombination random nanostructure consisting of conical structures and nanopores based on silicon substrate was prepared by plasma etching and chemical corrosion. The three-dimensional coordinate data of the recombination structure surface are obtained by atomic force microscopy, the radiation characteristics of the recombination random nanostructure is investigated by numerical calculation and experimental measurement, which has excellent antireflection characteristics over 300nm-1100nm. The influence of the incident angle and polarization state on the radiation characteristics are analysed.