Dapre rapò medya etranje yo, limyè -diyod ki emèt (LED) se ewo yo enkoni nan endistri ekleraj la. Yo opere avèk efikasite, gaye mwens chalè, epi yo dire yon bon bout tan. Koulye a, syantis yo ap travay sou yon nouvo materyèl pou fè LED pi efikas ak dire pi lontan pou aplikasyon pou konsomatè elektwonik, medikaman ak sekirite.
Researchers from the U.S. Department of Energy's (DOE) Argonne National Laboratory, Brookhaven National Laboratory, Los Alamos National Laboratory, and SLAC National Accelerator Laboratory report that they have prepared stable calcium for such LEDs Titanite nanocrystals. Research institutes from the Taiwan region of China also contributed to this research.
Perovskit yo se yon klas materyèl ki gen estrikti kristal espesyal ki absòbe ak emèt limyè, sa ki fè yo itil nan yon seri aplikasyon enèji -efikas, tankou selil solè ak divès kalite detektè.
Pandan ke nanokristal perovskit yo se kandida prensipal pou yon nouvo kalite materyèl ki ap dirije, yo te pwouve enstab nan tès yo. Ekip la estabilize nanokristal yo nan estrikti pore ke yo rekonèt kòm kad metal òganik, oswa MOF pou kout. Ki baze sou Latè-materyèl abondan epi ki fèt nan tanperati chanm, LED sa yo ta ka pèmèt yon jou -pi ba pri televizyon ak elektwonik konsomatè, pi bon aparèy imaj gamma-ray, e menm sistèm otonòm pou medikaman, optik sekirite, ak rechèch syantifik. Alimente detektè X-ray.
"We solved the stability problem of perovskite materials by encapsulating them in MOF structures," said Xuedan Ma, a scientist at the Center for Nanoscale Materials (CNM) in Argonne, DOE's Office of User Facilities, "Our research shows that this approach enables We can dramatically improve the brightness and stability of the luminescent nanocrystals."
Hsinhan Tsai, former JR Oppenheimer postdoc at Los Alamos University, added: "The interesting concept of incorporating perovskite nanocrystals in MOFs has already been demonstrated in powder form, but this is the first time we have successfully integrated them into the emissive layer of an LED. "
Tantativ anvan yo fabrike LED nanokristalin yo te antrave pa degradasyon nan nanokristal tounen nan faz esansyèl endezirab, ki retire avantaj ki genyen nan nanokristal ak diminye potansyèl yo kòm LED pratik. Matyè esansyèl konpoze de dè milya de atòm. Materyèl tankou perovskit yo fòme ak kèk a dè milye de atòm nan nanoskal la epi kidonk konpòte yo yon fason diferan.
Nan nouvo metòd yo, ekip la estabilize nanokristal yo pa fabrike yo nan yon matris nan MOF a, tankou yon boul tenis ke yo te sere pa fil fil fè. Yo te itilize nœuds plon nan fondasyon an kòm précurseurs metal ak sèl halogen kòm materyèl òganik. Solisyon sèl Halogen an gen bromur methylammonium, ki reyaji ak plon an nan kad la epi rasanble nanokristal alantou nwayo plon nan matris la. Depi matris la kenbe nanokristal yo separe, yo pa kominike ak degrade. Metòd la baze sou yon sèl-metòd kouch solisyon ki pi mwens chè pase pwosesis vakyòm ki lajman itilize jodi a pou fè LED inòganik.
MOF-LED estabilize ka pwodwi klere wouj, ble ak vèt limyè ak diferan tout koulè nan chak limyè.
"In this work, we demonstrate for the first time that perovskite nanocrystals stabilized in MOFs will create bright, stable LEDs in a variety of colors," said Wanyi Nie, a scientist at the Center for Integrated Nanotechnology at Los Alamos National Laboratory. "We can create different colors, improve color purity and increase photoluminescence quantum yield, a measure of a material's ability to emit light."
The research team used the Advanced Photon Source (APS) -- DOE's Office of Science User Facility in Argonne -- to perform time-resolved X-ray absorption spectroscopy, a technique that allowed them to discover changes in perovskite materials over time. Researchers can track the movement of charges through the material and learn important information about what happens when light is emitted.
"We can only do this with the powerful single X-ray pulse and unique temporal structure of APS," said group leader Xiaoyi Zhang in Argonne's X-ray Science Division, "We can track charged particles in tiny perovskite crystals. s position."
Nan tès durability, materyèl la fè byen anba radyasyon UV, chalè ak jaden elektrik san yo pa degrade ak pèdi deteksyon limyè li yo ak efikasite luminesans, yon kondisyon kle pou aplikasyon pratik tankou televizyon ak detektè radyasyon.
