We report the results of a theoretical study of the combined end-side pumped solar lasers to solve the problem associated with a recent experimental finding where the unexpected underperformance of the Ce doped Nd:YAG lasers in comparison to pure Nd:YAG lasers was observed. For this, we have developed a theoretical model based on space-dependent rate equations, which considers the effect of the thermal population of the laser levels on the laser output. It is shown that the main reason for the lower laser performance of recently experimentally realized Ce:Nd:YAG solar laser in the end-pumped regime and the fracture of the Ce:Nd:YAG rod at the process is the excessively high thermal load on the end of the laser rod. As a result of our study, we propose easily-feasible solutions based on optimal pumping and cooling configurations. The results of this study also demonstrate that under the necessary conditions, using Ce:Nd:YAG as an alternative to Nd:YAG in the combined end-side pumping configuration could increase the laser output by more than 1.5 times.

Radiative cooling, as a cooling method that does not consume any energy during operation, has become a hot topic in recent years. Unlike passive daytime radiative cooling in buildings, radiative coolers used in photovoltaic modules must also have high light transmittance, which undoubtedly makes relevant research more difficult. Currently, bifacial photovoltaic modules are widely available on the market, if traditional cooling methods are employed in the back of them, including passive cooling such as heat sink and active cooling such as air cooling and water cooling, it will block the rear irradiance into the module. Hence, radiative cooling is an excellent solution. In this paper, polycarbonate (PC) film and one composed with a high reflective layer are proposed. The former has high emissivity in the atmospheric window and the latter has high reflectivity in the near-infrared band. Both achieve a good cooling effect without affecting the normal operation of the module. We also prepared the reflective film on PC by magnetron sputtering, and its optical characteristics were also measured and compared with simulation results. We innovatively use PC material and combine the reflective film with quite simple structure. Compared with other research results, they are simpler and stabler film structures and have the advantages of low cost, easy installation, good cooling effect, and can be directly pasted on the surface of the photovoltaic module. It turns out that the cooling effect can reach 6.02°C with R-PC film and photoelectric conversion efficiency can be improved by 0.27% with PC film when h_c = 20 W · m ^{− 2} · K ^{− 1} and T_a = 27 ° C. Given its excellent performance, they have a broad application prospect in the daytime passive radiative cooling of bifacial photovoltaic modules.

Conventional dye-sensitized solar cells (DSSCs) require two transparent conductive oxide (TCO) glasses as working and counter electrodes and are one of the most costly components posing an appreciable cost burden for production and commercialization. To circumvent this issue, we propose a TCO-free device structure utilizing titanium (Ti) sheets as a substitute for TCO. This back contact device structure not only allows the removal of the costly TCO component from the working electrode but also enhances the extent of photons absorbed by the photoanode. A flat titanium sheet with microholes (FTS-MH) was successfully applied to fabricate cylindrical TCO-free-DSSCs) with a titanium sheet as a back contact electrode. When the H₂O₂ surface-treated FTS-MH substrate generating dense anatase TiO₂ nanosheets was used as a photoanode, there was a pronounced improvement in efficiency from 5.76% to 8.59%. This was mainly attributed to the lower interfacial resistance facilitated by improved electrical contact between the conducting FTS-MH substrate and mesoporous TiO₂ layer since enhancement in the dye loading was only 8.6%.

Low-cost and effective cocatalyst Ni₂O₃ was loaded on SrTiO₃ (STO) via a simple one-step hydrothermal method. The Ni₂O₃ / SrTiO₃ ( m ) photocatalysts were systematically characterized and applied to visible-light-driven CO₂ reduction to investigate their photocatalytic activity. The series of the Ni₂O₃-modified SrTiO₃ photocatalysts presented an improved photocatalytic activity and stability. Here, the N_5.4STO ( m ) catalyst showed the best photocatalytic activity, with CO and CH₄ yielding up to 11.57 and 1.51 μmol / g, respectively, under visible-light irradiation of 3 h, which were 3.15 and 14.84 times higher than that of pure STO(m), respectively. Based on the characterization and experimental results, the enhanced photocatalytic activity might be attributed to the following reasons: (1) Ni₂O₃ well dispersed on SrTiO₃ served as CO₂ attachment sites; (2) the modification of Ni₂O₃ could red shift the absorption edge and broaden the visible-light response ability; and (3) Ni₂O₃ nanoparticles act as electron traps to capture photogenerated electrons, effectively blocking the recombination of electron–hole pairs. The work offers important insights into the design of non-noble metal oxide cocatalyst modified photocatalysts for electron capture and photoreduction.

A multirod solar laser station for the megawatt solar furnace (MWSF) in Odeillo, France, was conceptualized and numerically studied to improve the solar-to-laser power conversion efficiency. 18 heliostats from the 63-heliostat field were selected, and 347 kW of solar power was obtained at its focus. From there, a two-dimensional compound parabolic concentrator further concentrated and redistributed the solar rays toward 11 core-doped Nd:YAG rods, each fixed inside a fused silica flow tube. 11.40 kW of total multimode laser power was calculated, corresponding to a 3.29% solar-to-laser power conversion efficiency. This efficiency value represents an enhancement of 1.70 and 1.26 times over that attained from single-rod solar laser systems in side-pumping configuration tested in Odeillo, France, in which Nd:YAG rods were codoped with Cr^{3 +} and Ce^{3 +} ions, respectively. It was also 1.44 times higher than that obtained by a previously proposed side-pumping scheme with a solar flux homogenizer and 12 Nd:YAG rods for the same MWSF.

For the employment of organic photovoltaic cells in wearable electronic systems, improvements in energy conversion efficiency and omnidirectionality (angular coverage) are highly appreciated. This study aims at those improvements by introducing shell-shaped active layers. The proposed device structures enhance light absorption and angular range through light coupling to guided modes in the active layer. Two shapes, i.e., a triangle and a semicircle, are examined for the shell cross-sections. Numerical simulation using finite-element analysis and finite-difference time-domain methods demonstrates that the devices with the triangular-shell-shaped active layers exhibit an average absorption enhancement of up to 63% for transverse electric (TE)-polarization and up to 32% for transverse magnetic (TM)-polarization when compared with the flat active layers of the same thicknesses. The average enhancements of the semicircular-shell-shaped active layers are found to be slightly lower than those values, with 60% for TE and 28% for TM. The examined structures also show good omnidirectionality with decent absorption up to an 81 deg incidence angle for the triangular-shell-shaped device and up to a 76 deg angle for the semicircular one when TM polarization is considered. These absorption enhancements and improved angular coverages make the proposed structures highly attractive for wearable electronic system applications.