Interfacial solar vapor generation (ISVG) was first proposed in 2014 and it has gained more and more attention from academia due to its tremendous improvement in evaporation efficiency compared with previous bottom and volumetric heating designs. With significant efforts put into this field, the current evaporation rate of the system can attain 4 kg m−2 h−1 under one sun irradiation. To catch up with the up-to-date development of ISVG systems, we prepare this review article to summarize the recent development in this field. In this review, we first introduce the constituent elements of an ISVG system, namely substrates and photothermal materials. Following this, several fabrication techniques for ISVG systems are highlighted to enable all-in-one ISVG architecture designs. The central parts of this review include the design principles and optimization strategies of ISVG systems, salt rejection and condensation strategies. Finally, various application scenarios, including seawater desalination, sterilization, and water-electricity/water-fuel production, are introduced in detail, followed by conclusions and future perspectives. ISVG is a green and low-cost technique for producing clean water driven by solar energy, which shows great application potential in remote and off-grid regions. With continuous efforts and improvement, it is envisioned that ISVG will become a complementary technique to current water treatment technologies soon.
ZnO nanoparticles were incorporated into quantum dot (QD)-silicone encapsulation materials of the light-emitting diodes (LEDs) to exploit their strong scattering effect, which were proved by the ZnO-only film experiment. The novel packaging scheme led to a decrease in the radiation flux because of the conversion-energy loss of QDs and backscattering of ZnO nanoparticles. Under the similar color coordinate, the luminous flux of the ZnO-incorporated QD-LED showed a 3.37% increase compared to the conventional structure. This was attributed to the scattering effect, which enhanced the utilization of blue light and the conversion of yellow light. And the angular-dependent correlated color temperature (CCT) deviation was reduced from 862 to 712 K in the range of -70° to 70°. Moreover, the CCT monotonically decreased, and the chromaticity coordinate steadily shifted to the yellow region as the amount of ZnO nanoparticles increased. Therefore, ZnO nanoparticles can be a favorable optical performance enhancer for the future generation of QD-converted LEDs.
Due to their good color rendering ability, white light-emitting diodes (WLEDs) with conventional phosphor and quantum dots (QDs) are gaining increasing attention. However, their optical and thermal performances are still limited especially for the ones with QDs-phosphor mixed nanocomposites. In this work, we propose a novel packaging scheme with horizontally layered QDs-phosphor nanocomposites to obtain an enhanced optical and thermal performance for WLEDs. Three different WLEDs, including QDs-phosphor mixed type, QDs-outside type, and QDs-inside type, were fabricated and compared. With 30 wt. % phosphor and 0.15 wt. % QDs nanocomposite, the QDs-outside type WLED shows a 21.8% increase of luminous efficiency, better color rendering ability, and a 27.0% decrease of the maximum nanocomposite temperature at 400 mA, compared with the mixed-type WLED. The reduced re-absorption between phosphor and QDs is responsible for the performance enhancement when they are separated. However, such reduced absorption can be traded off by the improper layered configuration, which is demonstrated by the worst performance of the QDs-inside type. Further, we demonstrate that the higher energy transfer efficiency between excitation light and nanocomposite in the QDs-outside type WLED is the key reason for its enhanced optical and thermal performance.
Angular color uniformity (ACU) is a key factor used to evaluate the light quality of white-light emitting diodes (LEDs). In this study, a novel double remote micro-patterned phosphor film (double RMPP film) was used to enhance the ACU of a remote phosphor (RP) down-light lamp. A conventional RP film and remote phosphor film with single micro-patterned film (single RMPP film) also were examined for comparison. The angular correlated color temperature (CCT) distributions and the optical performance of the films were experimentally measured. The measurement results showed that double RMPP film configuration exhibited better color uniformity with a CCT deviation of only 441 K, compared with 556 K for the single RMPP film configuration and 1390 K for the RP film configuration. A simulation based on FDTD and ray tracing combined method also confirmed the ACU improvement. In addition, compared with the conventional RP film, the luminous efficiency of single and double RMPP film configurations was increased by 6.68% and 4.69%, respectively, at a driving current of 350 mA. The enhancement of the ACU and luminous efficiency are due to the scattering and mixing effect of the micro-patterned film. Moreover, the double RMPP film configuration had better CCT stability at different currents than the other two configurations. The results demonstrated the effectiveness and superiority of double RMPP film in white LED applications.