Commercial Lighting Research Articles

Light Pollution Classification and Intervention Based on Assessment Models

With the rapid development of science and technology, landscape and outdoor commercial lighting have become essential but also aggravate light pollution, a new form of environmental pollution. This paper develops a light pollution risk level model and an intervention model. Three regions are selected using the TOPSIS model, considering population, precipitation, GDP, artificial light intensity, and sky brightness. An AHP-based intervention model evaluates cost, accident rate, biological comfort, and persistence. Strategies include reducing light duration and controlling nighttime lighting. For cities like Shanghai, using more glass curtain walls can help, while for sunny cities like Kunming, controlling nighttime lighting is effective. Based on previous studies, this paper compares major cities, obtains customised solutions for different cities, and quantifies light pollution risk level indicators.

Investigating the physicochemical, optical and microstructural properties of sodium doped CdO nano powders fabricated by co-precipitation technique for blue emission and antimicrobial applications

A series of cubic structured pristine and sodium doped CdO nanoparticles (Cd1-xNaxO NPs) with varying dopant concentrations have been synthesized using simple Co-precipitation process. Crystal structure and the connection between various structural parameters are evidenced using powder XRD diffractograms. The crystallite size is evaluated with different models and the mean crystallite size was reduced with Na ions doping concentration due to severe lattice distortion. The existence of various vibrational modes and functional groups were demonstrated through FTIR characterization. The signature of Cd–O and Na–O stretching modes were confirmed with FTIR. Raman spectra also confirmed the formation of metal–oxygen bond and the second order vibration features. The direct bandgap of the CdO material increased from 2.132 to 2.40 eV with an increase in the Na dopant content which presents the appearance of a blue shift as probed through UV–Vis spectroscopy. The surface morphology and microstructure of the samples were studied using FESEM and HRTEM images, respectively. EDAX measurements revealed the presence of Cd, and O in the host lattice and Cd, O and Na in the doped CdO constructions. The SAED concentric ring pattern of Cd1-xNaxO nanoparticles demonstrated the polycrystalline nature of the samples. PL study revealed the impression of intrinsic defects and the photoluminescence colour emission of the Cd1-xNaxO materials shifted more towards bright blue region as the Na doping concentration increased. CIE color coordinates of Na-doped CdO NPs shows intense bluish color and extending its applications in commercial UV lighting, blue LEDs and Fluorescent biological labelling and tagging. Cd1-xNaxO nanoparticles exhibited enhanced antibacterial activity with increasing Na doping content towards gram-positive, and gram-negative bacteria. Further, the antifungal analysis against C. albicans, and A. niger authenticate that Na+ substituted CdO nanoparticles shows excellent antifungal activity. The mechanism of the above observed results is examined in detail in this article.

Responses of mustard greens (Brassica juncea L.) to additional lighting duration of LED under greenhouse conditions in the tropical zone

ABSTRACT Light-emitting diodes have been beneficial for plant growth, especially for microgreens in countries with low radiation, greenhouses, and chambers. However, information about how plants respond to additional light-emitting diode lighting after 12 hours of sunlight exposure in tropical areas is limited. This study examines the effects of long-duration light-emitting diodes on mustard greens in Kien Giang province, Vietnam (105°14’33.21” E; 9°91’41.13” N). The trials were conducted in the greenhouse for two growing seasons with a completely randomized design, including 0, 2, 4, and 6 hours of assembled light-emitting diodes lighting and 4 hours of commercial light-emitting diodes lighting after 6 pm, with three replications. Results showed that weather factors in season 2 favorably influenced mustard’s growth. At 4 hours of lighting, commercial light-emitting diodes showed a higher chlorophyll index, flowering time, flowering rate, leaf number, and absolute growth rate of leaf number but less leaf and fresh shoot weight than assembled light-emitting diodes. Four hours of assembled light-emitting diodes positively affected most mustard growth, while 6 hours of assembled light-emitting diodes were superior for flowering aspects. Adding 4 hours of light-emitting diodes could increase leafy yield and shorten the harvesting time of mustard greens grown in greenhouses under tropical conditions.

Enhancing Emission and Stability in Na-Doped Cs3Cu2I5 Nanocrystals.

Lead-free Cs3Cu2I5 metal halides have garnered significant attention recently due to their non-toxic properties and deep-blue emission. However, their relatively low photoluminescence quantum efficiency and poor stability have limited their applications. In this work, sodium iodide (NaI) is used to facilitate the synthesis of Cs3Cu2I5 nanocrystals (NCs), demonstrating improved photoluminescence intensity, photoluminescence quantum yield, and stability. Systematic optoelectronic characterizations confirm that Na+ is successfully incorporated into the Cs3Cu2I5 lattice without altering its crystal structure. The improved Photoluminescence Quantum Yield (PLQY) and stability are attributed to the strengthened chemical bonding, which effectively suppresses vacancy defects in the lattice. Additionally, light-emitting diodes (LEDs) based on 10% NaI-doped Cs3Cu2I5 NCs were assembled, emitting vibrant blue light with a maximum radiant intensity of 82 lux and Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of (0.15, 0.1). This work opens new possibilities for commercial lighting display applications.

Improving efficiency in RGB phosphorescent and white organic light emitting diodes via donor-spiro-boron acceptor host materials

The universal host material with boron acceptor core structure is exceptionally sparse to be designed for red, green, and blue in efficient phosphorescent organic light emitting diodes (PhOLEDs) accompanying white OLEDs, possessing indistinguishable device feature. Herein, two boron acceptors spiro-host materials namely 1'-(4-(dimesitylboranyl)phenyl)-10-phenyl-10H-spiro[acridine-9,9′-fluorene] (TPA-PBM) and 1-(4-(dimesitylboranyl)phenyl)-3′,6′-dimethylspiro[fluorene-9,8′-indolo[3,2,1-de]acridine] (2MeCz-PBM) were designed and synthesized. The designed rigid donor strategy exhibited good device performance among the reported boron donor-spiro-acceptor (D-spiro-A) skeleton for organic light emitting diodes (OLEDs). In particular, we fabricate RGB three-color phosphorescent OLEDs based on TPA-PBM and 2MeCz-PBM. The red devices exhibit a maximum external quantum efficiency (EQE) of nearly 28 % (26.8 % for TPA-PBM and 27.5 % for 2MeCz-PBM), with an electroluminescence spectrum at 608 nm. The green/blue devices obtain maximum EQEs of 21.2 %/15.3 % and 21.8 % 17.3 %, for TPA-PBM and 2MeCz-PBM, respectively. Furthermore, green devices display an extremely low efficiency roll-off with decreasing 1 % and 3 % at luminance of 5000 cd m−2. Additionally, the two-color white OLED using 2MeCz-PBM exhibits EQEmax and PEmax are 24.5 % and 62.9 lm W−1 respectively, the EQE remain 23.8 % at commercial lighting brightness of 1000 cd m−2. The WOLED also shows a stable white spectrum with CIE varying range of (0.41, 0.47) to (0.39, 0.46) at 100 cd m−2 to 15000 cd m−2. All obtained results confirmed that our targeted molecules have advantage of carrier balance and efficient charge recombination, which might replace many other commercial host materials.

Efficient Large-Area (81 cm2) Ternary Copper Halides Light-Emitting Diodes with External Quantum Efficiency Exceeding 13% via Host-Guest Strategy.

Ternary copper (Cu) halides are promising candidates for replacing toxic lead halides in the field of perovskite light-emitting diodes (LEDs) toward practical applications. However, the electroluminescent performance of Cu halide-based LEDs remains a great challenge due to the presence of serious nonradiative recombination and inefficient charge transport in Cu halide emitters. Here, the rational design of host-guest [dppb]2Cu2I2 (dppb denotes 1,2-bis[diphenylphosphino]benzene) emitters and its utility in fabricating efficient Cu halide-based green LEDs that show a high external quantum efficiency (EQE) of 13.39% are reported. The host-guest [dppb]2Cu2I2 emitters with mCP (1,3-bis(N-carbazolyl)benzene) host demonstrate a significant improvement of carrier radiative recombination efficiency, with the photoluminescence quantum yield increased by nearly ten times, which is rooted in the efficient energy transfer and type-I energy level alignment between [dppb]2Cu2I2 and mCP. Moreover, the charge-transporting mCP host can raise the carrier mobility of [dppb]2Cu2I2 films, thereby enhancing the charge transport and recombination. More importantly, this strategy enables a large-area prototype LED with a record-breaking area up to 81 cm2, along with a decent EQE of 10.02% and uniform luminance. It is believed these results represent an encouraging stepping stone to bring Cu halide-based LEDs from the laboratory toward commercial lighting and display panels.

Study of Lighting Design for Interior Spaces

Due to the continuous progress of lighting fixture technology, people's requirements for commercial space design are also rising, and the comfortable, convenient, artistic, and technological combination of space is more and more emphasized by designers. The author has collected a large amount of visual subjective evaluation data through actual investigation and experimentation and conducted extensive and in-depth research on the light source's low radiation, luminous flux, luminous intensity, illuminance, luminance, color temperature, color deviation, color tolerance, beam angle, and maintenance coefficient. This paper takes the lighting quality parameters as the benchmark, analyzes the formal aesthetic relationship between commercial space and lighting design, and has a certain reference value for both lighting workers and academic research.

Effects of ultraviolet light supplementation on hen behaviour and welfare during early lay

Poultry can see in the ultraviolet (UV) spectrum and supplementation of UVA has been shown to reduce laying hens’ fear and stress. The shorter wavelengths (UVB) also facilitate vitamin D3 production. However, UV spectrums are typically not included in indoor commercial poultry lighting which may result in less than optimum welfare of laying hens. This study predicted that UVA and UVA/B supplementation would increase desirable behaviours such as foraging and exploratory pecking and reduce measures of fear and stress. The effects of UV light supplementation were assessed on 252 ISA Brown hens during the period from 16 to 27 weeks of age. Birds were housed in eighteen pens (14 hens/pen) under three different light treatment groups each with six replications: (i) UV0: standard control lighting with LED white light, (ii) UVA: control lighting plus a supplemental ‘daylight’ avian bulb providing UVA, and (iii) UVA/B: control lighting plus a supplemental full spectrum reptile bulb containing both UVA and UVB wavelengths. Behavioural time budgets were assessed in the home pens at 18 and 24 weeks. At 20, 23, and 26 weeks, assessments included: individual behavioural tests of tonic immobility and open field, pen-level novel object tests and blood heterophil/lymphocyte (H/L) ratios. At 27 weeks the UV supplemental lights were turned off for 3 days as a ‘stressor’ with bird locations in the pen measured before and during the stressor, along with H/L ratio and attention bias test assessments. Results showed limited effects of the supplemental lights. At 26 weeks both UV light treatments reduced tonic immobility duration (P = 0.006) and vocalisations across time in the open field test (P = 0.0003), while the UVA/B hens had lower H/L ratios than the UV0 hens (P = 0.01). However, removing the treatment lights did not result in greater stress and anxiety and there were few differences observed in the home pen time budgets. Overall, these results align with complementary findings in the same birds showing minimal impact of the UV treatments on measures of egg production, egg quality, bone health, and circulating plasma P and Ca but with an increase in serum vitamin D (25(OH)D3) for the UVA/B hens. The supplemental UV lights in this study were only on one side of the pens which could have minimised their impacts. Similarly, effects may vary at different points in the production cycle than included in this study.

Rapidly constructed water-resistant composite shell of fluoride red phosphors K2GeF6:Mn4+ by in-situ passivation

White light emitting diodes assembled with Mn4+-doped fluoride red light phosphors are perfect photoconversion devices, but their low water stability prevents them from being used in commercial lighting displays. In this work, in order to increase the moisture resistance of the K2GeF6:Mn4+ (KGFM) phosphor, the Mn4+-free composite shell was prepared by in-situ passivation method with reducing agent SnCl2, and K2GeF6:Mn4+@ K2GeF6, K2SnF6 (PKGFM) with moisture resistance was achieved, which the shell also prevents the energy transfer to the surface defects of the phosphor. The thermal stability and luminescence decay time of the PKGFM are enhanced after surface modification, and IQE was raised from 94.37 % to 96.08 %. After immersion in water for 480 min, the luminescence intensity of the modified phosphors was 91.65 % of its initial, and IQE could still maintain 94.58 %. The WLED prepared with PKGFM was aged at high temperature (85 °C) and high humidity (85 %), after aging for 288 h, the luminous efficiency of the WLED could maintain 83 % of the initial value, and its CCT and CRI were 2979 K and 89.5, indicating that it has excellent color stability. The aging test results further demonstrate that the PKGFM phosphor contained with the Mn4+-free composite shell has good moisture resistance.

Measurement of Vertical Dispersion and Pollution Impact of Artificial Light at Night in Urban Environment

Excessive artificial light disrupts our lives and poses health risks. In mixed-use urban areas, commercial lighting conflicts with residential activities. Vertical towers exacerbate the issue, as lower-level lighting affects higher-level occupants, and more research is needed to understand the vertical dispersion of light and its impact on sleep disturbance. This work offers a simple mathematical model for height dependence of illuminance in an urban building. It correlates basic measurements to reduce the values of the Exponent (n) and Linear (Coeff2) coefficients in a standard power-law curve. The collection of only a few data points can help to investigate the extent of the lighting spread at various floors of the building. Even with the complex lighting environment in Hong Kong, the methodology is exercised in 8 sample buildings from 4 different neighbourhoods to show the insights from the testing results. The heights of the studied buildings range from 3 to 18 stories, and they are for residential and mixed use. While the average measured illuminance at the street level was between 37 lx and 303 lx for the 4 neighbourhoods, the average illuminance across building heights was 14 lx to 247 lx. The existence of multiple light sources on building facades disrupts the simple inverse-square relationship with a single light source. The power n values range from approximately -1.7 to -0.8, while the Coeff2 values range from 61 to 7603 for the measured buildings. These variations indicate deviations from the assumption of a single source and suggest higher luminance and the presence of light sources at higher heights. With the simple inverse-square relationship, the proposed methodology can help to determine the height where the recommended limit can be met given the light situation at the street level.

Toward Highly Efficient Solution‐Processable OLEDs: Inkjet Printing of TADF Emissive Layer

AbstractThe fabrication of optoelectronic devices using low‐cost inkjet printing techniques is a topic of great interest to the scientific and industrial community and represents a step toward the full deployment of solution‐processable organic light emitting diodes (OLEDs), particularly for commercial lighting and signaling applications. Herein, the inkjet printing of tBuCzDBA (9,10‐bis(4‐(3,6‐di‐tert‐butyl‐9H‐carbazol‐9‐yl)−2,6‐dimethylphenyl)−9,10‐diboraanthracene) is reported, a high‐performing thermally activated delayed fluorescence (TADF) emitter for OLEDs. Optimizing the surface tension values of the ink formulations and the associated wetting behavior are crucial parameters for achieving a uniform and homogeneous printed thin film. In particular, it is observed that using a proper mixture of solvents with different surface tensions, it is possible to generate Marangoni flows inside the drop, which triggers a very fast drying process, ensuring optimized morphological and optical properties in the inkjet printed tBuCzDBA‐based film. OLEDs exploiting this film as an emissive layer are then fabricated, achieving a maximum luminance of 32 000 cd m−2, a current efficiency of 27.5 cd A−1, and an external quantum efficiencyof 10%. To the best of the knowledge, this is the highest efficiency reported to date for self‐hosted TADF inkjet‐printed OLEDs.

Grid-scale demand-side flexibility services using commercial buildings lighting loads

Flexibility Services can be used to account for the high variability in electricity generation due to increasing renewable energy sources such as wind and solar energy. As buildings become smarter with the adoption of new technologies for sensing and control, more integration between buildings and the electric grid is possible. Building loads such as air conditioning and lighting in commercial buildings have the potential to provide these Flexibility Services. In commercial buildings, lighting accounts for approximately 10–15 % of the load at time. Past studies have shown that lighting can be dimmed by 15–20 % without causing visual discomfort to the occupants. Overall, this study aims to estimate the instantaneous demand reduction that can be provided due to lighting loads using prototypical building models aggregated across electric grid nodes in the Midcontinent Independent System Operator (MISO) region in the United States. Findings suggest, in a future case with 100 % LED fixtures and 30 % technology penetration for smart lighting controls, lighting loads can provide around 250 to 475 MW (0.21 to 0.39 % of MISO’s peak load) of Flexibility Services in the MISO region. The results can be used as inputs for grid levels models to predict future generation, transmission, and distribution investments for future high renewable energy scenarios.

Bi-Level Dimmable LED Driver in Refrigerated Display Lighting Systems

Commercial refrigerated display lighting (RDL) systems require LED drivers to provide constant 24 V to multiple LED light bars connected in parallel, each with a built-in current regulator to maintain a constant output brightness. The system uses a passive infrared motion detector to detect approach of people and a dimmer controller to further reduce the power consumption of the LED light bars. RDL system typically requires 100% and 20% only brightness control, so the dimmer controller can be replaced by a 0-10 V dimmable LED driver. By connecting a fixed resistor to the 0-10 V dimming interface, the brightness output can be set to 20%. However, the wiring of this technique is complex. This brief presents a new bi-level dimmable LED driver design that uses an astable multivibrator and totem pole gate driver integrated PWM dimming circuit to achieve a 20 brightness output through a single dimming wire, simplifying system wiring. The driver’s dimming wire is connected to the 24 V output voltage through the AC-powered passive infrared motion detector’s built-in relay, turning on the PWM dimming circuit to generate a 20% duty square wave signal that drives the internal series MOSFET at a frequency higher than 1.25 kHz to avoid LED flicker. This new design has been proven to have the advantages of high efficiency, low cost and easy wiring, and it can replace dimmer controller and 0-10 V dimmable LED driver in RDL applications.

Structural and Photoluminescence Characterization of Oxyfluorides for Phosphor Applications

ConspectusRare-earth-containing phosphors were crucial to the advances made to compact fluorescent lamps (CFLs), which assisted in protecting a widely used halophosphate phosphor from degrading after exposure to a high ultraviolet flux. The CFL phosphors are often coated twice by depositing a light coat of rare-earth-containing phosphors over the inexpensive halophosphate phosphor, which generates white light with high efficacy and a good color rendering index and possesses a balance between phosphor cost and performance. Costs of phosphors can be mitigated by requiring lower rare-earth ion concentrations or by completely eliminating rare-earth ions, which was one of the main goals of investigating the oxyfluorides Sr3AlO4F and Ba2SrGaO4F as potential phosphors. Changes in the Sr3AlO4F and Ba2SrGaO4F structures were studied using high-resolution neutron diffraction annealing these materials in 5%H2/95%Ar and 4%H2/96% Ar, respectively. Annealing in these atmospheres causes self-activated photoluminescence (PL) to occur under 254 nm light, which makes them ideal materials for rare-earth-free CFL phosphors. Additionally, these hosts possess two distinct sites for isovalent or aliovalent substitution of Sr denoted as the A(1) and A(2) sites. Ga3+ can be substituted for Al3+ at the M site, which is known to have an impact on the self-activated PL emission color. The structural distortions noted included closer packing in the FSr6 octahedrons and AlO4 tetrahedrons in the Sr3AlO4F structure as compared to in air-annealed samples, which show no PL emission. Temperature-dependent studies reveal that both the air- and reductively annealed samples have identical thermal expansion within this temperature range (3-350 K). High-resolution neutron diffraction at room temperature confirmed the tetragonal structure (I4/mcm) for Ba2SrGaO4F, a novel material in the Sr3AlO4F family of materials, has been synthesized via a solid-state method. Analysis of the refined Ba2SrGaO4F structure at room temperature revealed expansion in the lattice parameters and its polyhedral subunits between the reductively annealed and air-annealed samples, which are correlated with the PL emission. Previous studies related to the application of these host structure types revealed that they have potential as commercial solid-state lighting phosphors due to their ability to resist thermal quenching as well as accommodate various levels of substitutions that will assist with color tunability.

Synthesis of Pb‐free Double‐Perovskite Heterojunction (Cs2SnCl6‐Bi3+&Te4+/Cs2GeF6‐Mn4+) with White Emission for LED Application

AbstractLead‐free halide double perovskites have been extensively studied for their application in the display and lighting fields. Owing to their characteristic single white luminescence, double perovskites have led to several developments in the field of white light illumination. However, most of these materials possess poor ambient stability or produce white emissions with high correlated color temperature (CCT) and low color rendering index (Ra), which hinder their application to home and commercial lighting displays. To address these challenges, a Pb‐free double perovskite heterojunction phosphor for white light is designed, namely Cs2SnCl6‐2%Bi3+&4%Te4+/Cs2GeF6‐0.11%Mn4+, which has a low CCT of 3525 K, a high Ra of 90.5, good optical moisture and thermal stability. The pattern and mechanism of epitaxial growth are derived from structural and surface tests. Analyzing the optical properties clarifies the existence of energy transfer modes in this heterojunction material, i.e., from Bi3+ to Te4+, from Bi3+ to Mn4+, and from Te4+ to Mn4+. These results indicate the application prospects of these heterojunction phosphors in the field of white light illumination.

Commercial Lighting Design in Human-Centered Lighting Concept

In this study, the lighting design of a building in the Organized Industrial Zone, which was converted from a warehouse to a commercial kitchen, was designed according to the Human-Centered Lighting concept. Point lighting calculations were made for commercial kitchen environments with artificial lighting. In order to reduce the negative effects of lighting on human health, lighting that will not disrupt the circadian rhythm should be provided. By using direct lighting, without changing the architectural design, it has been tried to provide optimum lighting suitable for human biology with low-cost artificial lighting arrangements. According to WELL standards, an average of at least 500 lux conditions should be provided in the relevant work area on counters and other food preparation or production areas in Commercial Kitchen Lighting. This area, which was designed as a warehouse for this purpose, was designed as a commercial kitchen in terms of lighting. As a result of the design, a lighting design was made in accordance with the WELL standards according to the Human-Centered Lighting concept. In this way, the visual comfort of the working personnel is improved and optimum circadian effects are provided.

Construction of visual evaluation system for building block night scene lighting based on multi‐target recognition and data processing

AbstractThe rapid development of night tourism economy has made people's demand for night scene lighting in architectural blocks increasing, and the night scene lighting situation of urban architectural blocks has gradually received people's attention and attention. Achieving good night lighting visual effects of building blocks can not only meet the needs of residents for entertainment and consumption at night, but also beautify the image of blocks and promote the economic development of building blocks. However, due to the unreasonable planning and management of the night scene lighting design of architectural blocks in some areas, improper application of night scene lighting, and overly commercial night scene lighting effects, it affects people's normal night activity needs and has a negative impact on the long‐term block economy of the region. Faced with this situation, the night lighting of architectural blocks and its problems is studied and photos are identified with high lighting visual effect evaluation using multi‐target identification and data processing to construct a night lighting visual evaluation system for architectural blocks, and also an experimental study of the visual evaluation system is conducted. The results show that the overall visual suitability evaluation support rate of the respondents for the night scene lighting of architectural blocks is 95.64%, and the visual evaluation system proposed in this paper is reasonable and effective, which is conducive to promoting the improvement of the visual effect of night scene lighting in architectural blocks.

Influence of extended surface area of heatsink on heat transfer: design and analysis

PurposeLight emitting diode (LED) has been the best resource for commercial and industrial lighting applications. However, thermal management in high power LEDs is a major challenge in which the thermal resistance (Rth) and rise in junction temperature (TJ) are critical parameters. The purpose of this work is to evaluate the Rth and Tj of the LED attached with the modified heat transfer area of the heatsink to improve thermal management.Design/methodology/approachThis paper deals with the design of metal substrate for heatsink applications where the surface area of the heatsink is modified. Numerical simulation on heat distribution proved the influence of the design aspects and surface area of heatsink.FindingsTJ was low for outward step design when compared to flat heatsink design (ΔT ∼ 38°C) because of increase in surface area from 1,550 mm2 (flat) to 3,076 mm2 (outward step). On comparison with inward step geometry, the TJ value was low for outward step configuration (ΔTJ ∼ 6.6°C), which is because of efficient heat transfer mechanism with outward step design. The observed results showed that outward step design performs well for LED testing by reducing both Rth and TJ for different driving currents.Originality/valueThis work is authors’ own design and also has the originality for the targeted application. To the best of the authors’ knowledge, the proposed design has not been tried before in the electronic or LED applications.

A design‐oriented approach for managing colored light sources in lighting design software

AbstractIn the last decade, the extensive introduction of LED lighting sources has brought elements of innovation to interior lighting design in terms of color. Besides the new tunable white LED source, lighting is no longer exclusively white; indeed, colored lighting has entered the design practice thanks to the positive effects on people's health and mood. Unfortunately, this element of lighting innovation, color, cannot be computed correctly in commercial lighting design software. These computations are based on the assumption that light is only white or defined in terms of RGB triplets in the relative digital color space of computer graphics, which does not have a physically correct relationship with the actual spectral power distribution (SPD) of luminaires. In this paper, attention is focused on a practical design‐oriented approach for describing luminaires in lighting design software that also considers the real SPD and the luminous intensity distribution. The focus is on information available to lighting designers who do not have a laboratory to measure light sources and luminaires. This information could be available in online datasheets or as a Cartesian graph from luminaires and light sources manufacturers. Following this approach, a set of functions is proposed that can be easily implemented in lighting design software to improve light sources' color management and allow lighting designers to add SPD data to luminaires.

Frequency modulated hybrid nanogenerator for efficient water wave energy harvesting

The energy crisis and environmental pollution are the two major challenges facing humanity, and harvesting energy from the ocean is a promising solution. In this paper, a triboelectric-electromagnetic-piezoelectric hybrid energy harvester (TEP-HEH) for low frequency wave energy harvesting is presented. With the introduction of the cantilever beam structure, the vibration frequency is converted from 0.2 Hz (simulated wave frequency) to 7.2 Hz, which greatly improves the energy harvesting performance of the electromagnetic generator (EMG) and the piezoelectric nanogenerator (PENG) modules. By broadening the frequency bandwidth of wave energy harvesting, a large power density of 5.73 W m−3 is obtained for the TEP-HEH. Besides, the output performance of TENG, EMG, and PENG modules is investigated and the connection mode of the three types of modules is discussed. The TEP-HEH can light up a commercial lighting bulb with a rated power of 5 W or power small electronics. This work provides an efficient solution for low frequency wave energy harvesting and the realization of the blue-energy dream.