Tuning the spectrometric properties of white light by surface plasmon effect using Ag nanoparticles in a colour converting light-emitting diode

摘要: abstract We report on the spectral tunability of white light by localized surface plasmon (LSP) effect in a colourconverting hybrid device made CdSe/ZnS quantum dots (QDs) integrated InGaN/GaN blue light-emitting diodes (LEDs). Silver (Ag) nanoparticles (NPs) are mixed with QDs for generating LSP effect.When absorption Ag NPs is synchronized to QW emission at 448 nm, selec-tively absorb and subsequently enhance QD emission. Using this energy transferscheme, (x, y) chromaticity coordinates LED was tuned from (0.32, 0.17) to(0.43, 0.26), thereby generated warm correlated colour temperature(CCT) around 1800 K. Moreover, 47% enhancement external efficiency (EQE) wasrealized. 2010 Elsevier Ltd. All rights reserved. 1. IntroductionHybrid (LEDs) based InGaN/GaNquantum-well (QW) and/or ultraviolet semiconduc-tor as converters currently attract-ing great deal attention applications such generallighting displays [1–6]. In typical device, QDsare optically pumped an electrically drivenQW, collective luminescence different emissions pro-duce light. The advantage structure isthe controlled due tun-ability together large yields high photostabilityof luminophors, comparedto conventionalphosphors.Basedonthis fact, core–shell type [3,5],CdSe/ZnS/CdSe [4], CdSe/CdS [2], CdSe/ZnSe [6], CdSe//ZnS/CdSZnSand CdSe/CdS/ZnS/CdSZnS [1] have been utilized, lightemission tunable spectrometric properties has demon-strated. Recently, liquid-crystal display (LCD) panel utilizing hy-brid backlight also demonstrated [1]. Thesestudies showed that tristimulus operating point cor-related temperature (CCT) greatly alteredby concentration mixing ratio QD-to-QWemissions, which relies (EQE)of LED.Recently, photonic interactions noble metallic nanoparti-cles being explored GaN-based LEDs several rea-sons [5,7,8]. coupling collectiveoscillations electron density called plasmons (SPs)is shown exhibit strong electroluminescence (EL) enhancement,even QW–NP separation distances over 200 nm [7]. cou-pling scheme, emitter can be transferredinto SP modes then radiates effective emissionefficiency enhanced. Conversely, metal inci-dent transfer into nearby absorber suchthat its This behaviour beenwell documented semiconductor located near NPs[9–11]. scheme exploited ahybrid converting output blue/green two-colour red [5]. general, SPs cancause or quenching fluorescence tothe competition between field nonradiative en-ergy SPs. However, interplay revealed dependalso size shape NPs,the interparticle distance, concentration, relation-ship QDsandthe extinctionspectrumof metalNPs.In letter,we pro-pose demonstrate mechanism exploit SPeffect tuning LEDs.In order generate effect, amount aremixed (emission 580 nm) polymer ma-trix, top