一种低损耗轻型环保天线罩的设计及应用

从分析天线罩对天线辐射性能的影响及天线安装机械强度的要求出发,在结构设计、材料选择及成型工艺等方面进行综合考量,设计出一种全新的结构形式及成型工艺,实现了天线罩辐射面低介电/低损耗、低密度,非辐射面高机械强度。经过仿真对比分析,该设计可使3.5 G频段天线平均增益提升0.2~0.3 dB,解决了现有天线罩技术存在的各种问题,真正全面实现了天线罩的低介电/低损耗、轻量化,而且表面质量更好,更加绿色环保,是5G时代天线的理想选择。

Large improvement of photovoltaic performance of flexible perovskite solar cells using a multifunctional phospho-ethanolamine-modified SnO_(2)layer

The non-radiative recombination loss caused by diverse defects within SnO_(2)electron transport layer(ETL),perovskite film,and their interface greatly hinders the further improvement of the performance and stability of flexible perovskite solar cells(PSCs).Therefore,it is urgent to develop an effective strategy to address these issues.Herein,a multifunctional material,phospho-ethanolamine(PE),is introduced into SnO_(2)aqueous colloids to suppress defects and prepare high-quality ETL.The results demonstrate that the incorporation of PE can significantly reduce the number of Sn dangling bonds due to the formation of new Sn–O–P bonds,which is beneficial to ameliorating the electrical properties of SnO_(2)and obtaining dense SnO_(2)film.Meanwhile,the amino group(NH_(2))of PE can interact with uncoordinated Pb^(2+)in perovskite,thereby suppressing SnO_(2)/perovskite interface defects and obtaining improved perovskite film quality.Consequently,the optimized flexible and rigid PSCs based on the SnO_(2)-PE composite ETL yield outstanding photoelectric conversion efficiency(PCE)of 18.48%and 21.61%,respectively.Moreover,flexible PSCs based on SnO_(2)-PE present excellent mechanical durability,and 90.6%of the original PCE is retained after 1000 bending cycles.

Radiative entransy flux in enclosures with non-isothermal or non-grey,opaque,diffuse surfaces and its application

The spectral radiative entransy flux and the total radiative entransy flux are defined for the steady radiative heat transfer processes in enclosures composed of non-isothermal or non-grey, opaque, diffuse surfaces. Based on the definitions, the radiative entransy flux balance equation and the radiative entransy dissipation functions are introduced under spectral and total wavelength condition. Furthermore, the minimum principle of radiative entransy loss, the extreme principle of radiative entransy dissipation and the minimum principle of radiative thermal resistance are developed. The minimum prirlciple of radiative en- transy loss shows that the potential and the net radiative heat flux distribution which meet the control equations and the boundary conditions would make the radiative entransy loss minimum if the net radiative heat flux or the potential distribution of the radiative heat transfer system is given. The extreme principle of radiative entransy dissipation indicates that the minimum radiative entransy dissipation leads to the minimum average potential difference for the prescribed total radiative heat exchange and the maximum radiative entransy dissipation leads to the maximum radiative heat exchange for the prescribed average potential difference. Moreover, the minimum principle of radiative thermal resistance tells us that the aforementioned extreme values of radiative entransy dissipation both correspond to the minimum value of radiative thermal resistance. Application examples are given for the extreme principle of spectral radiative entransy dissipation and the minimum principle of spectral radiative thermal resistance, and the principles are proved to be applicable.

Photo-stable perovskite solar cells with reduced interfacial recombination losses using a CeO interlayer

Despite demonstrating remarkable power conversion efficiencies(PCEs), perovskite solar cells(PSCs) have not yet achieved their full potential. In particular, the interfaces between the perovskite and charge transport layers account for the vast majority of the recombination losses.Interfacial contact and band alignment between the lowtemperature-processed TiO_(2) electron transport layer(ETL)and the perovskite are essential to minimize nonradiative recombination losses. In this study, a CeOx interlayer is employed to modify the perovskite/TiO_(2) interface, and the charge transport properties of the devices are investigated. The bilayer-structured TiO_(2)/CeOx ETL leads to the modification of the interface energetics, resulting in improved electron extraction and reduced nonradiative recombination in the PSCs.Devices based on TiO_(2)/CeOx ETL exhibit a high open-circuit voltage(Voc) of 1.13 V and an enhanced PCE of more than 20%as compared with Vocof 1.08 V and a PCE of approximately 18% for TiO^(2-)based devices. Moreover, PSCs based on TiO_(2)/CeOx ETL maintain over 88% of their initial PCEs after light illumination for 300 min, whereas PSCs based on TiO_(2) ETL almost failed. This study provides an efficient strategy to enhance the PCE and stability of PSCs based on a lowtemperature-processed TiO_(2) ETL.