Lead halide perovskite quantum dots (PQDs) display remarkable photoelectric performance. However, defects such as weak stability in air and water environments limit the development of lead halide PQDs in solid-state light applications. Herein, centrifugal spinning is used for the fabrication of stable luminous CsPbBr3 PQD nanofibers. After immersion in water for 11 months, the PQD fibers still maintained considerable photoluminescence quantum yield, showing high stability in hostile environments. The water-stability mechanism of the fibers can be explained by the changing defect density, crystal growth of PQDs, and the molecular transformation at the fiber surface. The white LED based on the CsPbBr3 fibers exhibits satisfying color gamut performance (128% of National Television System Committee). Due to the short photoluminescence lifetime of CsPbBr3 PQDs, the communication potential is also considered. The CsPbBr3 fibers obtained by centrifugal spinning present a bandwidth of 11.2 MHz, showing promising performance for solid-state light and visible light communication applications.

Perovskite light emitting diodes (PeLEDs) have attracted considerable research attention because of their external quantum efficiency (EQE) of >20% and have potential scope for further improvement. However, compared to red and green PeLEDs, blue PeLEDs have not been extensively investigated, which limits their commercial applications in the fields of luminance and full-color displays. In this review, blue-PeLED-related research is categorized by the composition of perovskite. The main challenges and corresponding optimization strategies for perovskite films are summarized. Next, the novel strategies for the design of device structures of blue PeLEDs are reviewed from the perspective of transport layers and interfacial layers. Accordingly, future directions for blue PeLEDs are discussed. This review can be a guideline for optimizing perovskite film and device structure of blue PeLEDs, thereby enhancing their development and application scope.

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.

To further improve the luminous efficiency of LED lightings, this Letter proposes a chip-on-board (COB) device by combining diced staggered V-shaped patterns and remote phosphors. The results show that the V-shaped patterned COB (V-COB) with vertex angles from 120o to 150o can achieve a ～17% output power increase (OPI) compared to the conventional COB. V-COB remote phosphor devices (RPDs) are then manufactured and tested. The luminous efficiency of the proposed RPD represents an 11.6% increase at the correlated color temperature of ～3000 K. Such an improvement can be attributed to both the decreases of total internal reflections and phosphor backscatterings.

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 micropatternedfilm. 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.