Energy-saving quality road lighting with colloidal quantum dot nanophosphors

Abstract

Abstract:Here the first photometric study of road-lighting white light-emitting diodes (WLEDs) integrated with semiconductor colloidal quantum dots (QDs) is reported enabling higher luminance than conventional light sources, specifically in mesopic vision regimes essential to street lighting. Investigating over 100 million designs uncovers that quality road-lighting QD-WLEDs, with a color quality scale and color rendering index ≥ 85, enables 13-35% higher mesopic luminance than the sources commonly used in street lighting. Furthermore, these QD-WLEDs were shown to be electrically more efficient than conventional sources with power conversion efficiencies ≥ 16-29%. Considering this fact, an experimental proof-of-concept QD-WLED was demonstrated, which is the first account of QD based color conversion custom designed for street lighting applications. The obtained white LED achieved the targeted mesopic luminance levels in accordance with the road lighting standards of the USA and the UK. These results indicate that road-lighting QD-WLEDs are strongly promising for energy-saving quality road lighting.

Excitonic improvement of colloidal nanocrystals in salt powder matrix for quality lighting and color enrichment

“…Semiconductor colloidal nanocrystals, which offer favorable and unique optical properties such as narrow and tunable emission, broad absorption, and high quantum efficiencies [1], have been in the center of interest in numerous fields from biology [2] to photonics [3]. After twenty years of their first colloidal synthesis, today these materials are utilized in various applications including displays [4,5], sensors [6], solar-cells [7], and illuminants for general [8][9][10] and outdoor lighting [11]. Their main Achille's heel is the problems associated with their deterioration occurring due to their moderate stability as well as limited compatibility with the encapsulants and fabrication techniques.…”

How to Design Quality Light Sources With Discrete Color Components

“…To take this variation into account, in Ref. [6] the design requirements for achieving high-quality lighting with nanocrystal quantum dots are established. This study starts with determining the luminance levels to satisfy the existing road lighting standards, which vary significantly depending on the country.…”

“…These are 0.50, 0.80, 1.25, and 1.75 cd/m 2 which are named in Ref. [6] as Mesopic 1, 2, 3, and 4, respectively. Next, the performance of the commercial white light sources was evaluated.…”

Improvements of mesopic luminance for light-emitting-diode-based outdoor light sources via tuning scotopic/photopic ratios

“…In order to fulfill the road lighting standards in the USA [20,21] for the freeway (0.40 -0.60 cd/m 2 ), collector (0.40 -0.80 cd/m 2 ), and local road lighting (0.30 -0.60 cd/m 2 ) conditions, we choose the L p of 0.5 cd/m 2 . Under such a circumstance, the optimized mesopic luminance L mes (shown in Fig.…”