Nyob rau hauv lub tshav pob ntawm perovskite electroluminescent li (PeLEDs), kev ua tau zoo ntawm xiav electroluminescent li lags qab lwm yam khoom siv zoo sib xws vim tsis muaj txoj kev fabrication. Ntawm no, cov kws tshawb fawb los ntawm Beijing Institute of Technology, Dalian Research Institute of Chemical Physics, Chinese Academy of Sciences, thiab Shanghai Institute of Applied Physics, Suav Academy of Sciences siv 2-phenylethylamine bromide (PEABr) thiab 3,3-diphenylpropylamine bromide (DPPABr) . ) ntawm cov ligands sib xyaw los npaj CsPbClBr2 nanocrystalline films hauv qhov chaw. Kev sib xyaw ntawm ob lub ligands ua ke ua rau muaj zog xiav lub teeb emission ntawm 470 nm nrog photoluminescence quantum yield siab li 60 feem pua vim yog qhov tsim ntawm nqaim quantum zoo dav faib. Rau lub hauv paus no, cov khoom siv xiav perovskite muaj txiaj ntsig zoo nrog qhov siab tshaj plaws sab nraud quantum efficiency ntawm 8.8 feem pua tau txais ntawm 473 nm.
The related paper was published in the journal Nature Communication with the title "Dimension control of in situ fabricated CsPbClBr2 nanocrystal films toward efficient blue light-emitting diodes".
Perovskite light-emitting diodes (PeLEDs) have emerged as an emerging display technology due to their high color purity, high external quantum efficiency (EQE), and solution processability. Taking advantage of the ionic properties of metal halide perovskites, PELEDs can be directly fabricated by an in-situ fabrication technique of spin-coating perovskite precursor solutions on target substrates. Since room-temperature-operating perovskite electroluminescence (EL) devices were first reported in 2014, green, red, and near-infrared PeLEDs have achieved maximum EQEs of over 20 percent , comparable to organic light-emitting diodes and quantum dot light-emitting diodes. However, the performance of blue PeLEDs still lags behind their green, red, and near-infrared light-emitting diodes, especially for display applications in the pure blue region (455–475 nm), which is an obstacle to the development of full-color display technologies.
Feem ntau, spectral modulation ntawm perovskite- hom emitters tuaj yeem ua tiav los ntawm kev sib xyaw, qhov loj me, thiab / lossis qhov loj me. Los ntawm kev txo qhov loj ntawm cov perovskites loj lossis nthuav qhia cov halides sib xyaw, peb -dimensional perovskite nanocrystals nrog xiav emission tau ua tiav tiav. Txawm li cas los xij, cov teeb meem kev ua tau zoo thiab kev ruaj ntseg ntawm cov khoom siv xiav electroluminescent raws li cov khoom me me no -sized perovskite nanocrystals feem ntau yog vim muaj kev lim dej nyuaj thiab theem sib cais.
Lwm lub tswv yim kom ua tiav siab -kev ua tau zoo xiav PeLEDs yog los tsim quasi-ob-dimensional (quasi-}2D) perovskite lug nrog ntau lub qhov dej quantum. Lub photoluminescence (PL) cov khoom ntawm cov quasi-2D perovskites yog ze ze rau kev hloov hluav taws xob los ntawm me me mus rau qhov loj n. Nws tau pom tias lub tiaj tiaj quasi-2D perovskite quantum zoo dav faib (QWD) yog qhov tseem ceeb rau kev yooj yim rau kev thauj mus los thiab txo qis zog ntxiv rau kev paub txog cov khoom siv hluav taws xob photovoltaic. Txawm li cas los xij, qhov cuam tshuam ntawm QWD ntawm EL cov cuab yeej tau kawm tsawg dua.
Nws paub tias QWD tuaj yeem tswj tau los ntawm kev kho qhov sib piv ntawm cov khoom sib xyaw ua ntej lossis los ntawm ligand engineering. Ntawm no, nws tau pom tias kev siv dual ligands yog ib lub tswv yim zoo los tswj QWD ntawm CsPbClBr2 nanocrystalline films npaj rau hauv qhov chaw. 2-Phenylethylamine bromide (PEABr) yog ib qho ligand zoo rau kev tsim cov n domains me me, thaum 3,3-diphenylpropylamine bromide (DPPABr) yog ib qho ligand zoo rau kev tsim cov n loj. Kev txiav txim siab txiav txim siab ntawm qhov piv ntawm ob lub ligands tuaj yeem nqaim QWD nrog lub hauv paus domination ntawm n=4.
Qhov kev tswj qhov loj me no ua kom yooj yim rau kev hloov pauv lub zog, ua rau muaj zog xiav lub teeb emission ntawm 470 nm wavelength nrog PL quantum yield (PLQY) siab li 60 feem pua. Siv dual ligands nrog lub tswv yim los tsim cov npe me me thiab cov npe loj n yog ib lub tswv yim muaj txiaj ntsig kom ua tiav QWD nqaim rau kev txhim kho PL cov khoom. Raws li qhov ua tau zoo ntawm cov yeeb yaj kiab nyias npaj los ntawm kev sib xyaw PEABr thiab DPPABr, siab -cov khoom siv hluav taws xob xiav hluav taws xob nrog qhov siab tshaj plaws EQE ntawm 8.8 feem pua ntawm qhov wavelength ntawm 473 nm. (Tej ntawv: Aisin Gioro Star)
Fig. 1 Cov yam ntxwv ntawm CsPbClBr2 nanocrystalline nyias zaj duab xis. Schematic daim duab ntawm lub hauv -situ npaj txheej txheem ntawm CsPbClBr2 nanocrystalline nyias films. Kev sib raug zoo ntawm kev siv ib qho q ntawm GIWAXS qauv ntawm CsPbClBr2 nanocrystalline films nrog ntau qhov sib txawv ntawm DPPABr thiab PEABr tau kawm.
Fig. 2 Kev ntsuas qhov muag ntawm CsPbClBr2 nanocrystalline nyias zaj duab xis. Steady-state photoluminescence spectra, absorption spectra thiab b-PLQYs ntawm CsPbClBr2 nanocrystalline films nrog qhov sib txawv ntawm DPPABr thiab PEABr tau kawm.
Fig. 3 The effect of QWD on its carrier dynamics. a, b Peak FWHM evolution extracted from broad bleached peaks (425–470 nm) of D0P8, D4P4 and D8P0 samples. c Schematic illustration of the carrier behavior after excitation. The carrier recombination process can be divided into five stages: I, carrier formation; II, exciton transfer; III, charge transfer; IV, reverse charge transfer; V, continuous charge transfer and recombination.
Figure 4 Blue perovskite device features. Energy level diagram of an electroluminescent device. Cross-sectional TEM image of a multilayer electroluminescent device. c EL spectra at 3.6, 4.4 and 5.2V forward bias. d Current density-brightness-voltage characteristics of the best performing device. EQE – Voltage characteristics of optimal performance equipment. f Maximum EQE histogram of 28 devices.
