Perovskit elektroluminesans qurilmalari (PeLED) sohasida ko'k elektrolyuminessent qurilmalarning ishlashi ishlab chiqarish usullarining yo'qligi sababli boshqa shunga o'xshash qurilmalardan orqada qoladi. Bu yerda Pekin texnologiya instituti, Xitoy Fanlar akademiyasi Dalian Kimyoviy fizika tadqiqot instituti va Xitoy Fanlar akademiyasi Shanxay amaliy fizika instituti tadqiqotchilari 2-feniletilamin bromid (PEABr) va 3,3-difenilpropilamin bromid (DPPABr) dan foydalanganlar. . ) CsPbClBr2 nanokristal plyonkalarini in situ tayyorlash uchun aralash ligandlardan. Ikki ligandni bir-biriga aralashtirish natijasida 470 nm chastotada kuchli ko'k yorug'lik emissiyasi paydo bo'ldi va tor kvant quduq kengligi taqsimotining shakllanishi tufayli fotoluminesans kvant rentabelligi 60 foizga etdi. Shu asosda 473 nm da maksimal tashqi kvant samaradorligi 8,8 foiz bo'lgan yuqori samarali ko'k perovskit qurilmasi olindi.
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.
Umuman olganda, perovskit{0}} tipidagi emitentlarning spektral modulyatsiyasiga kompozitsiyani, hajmini va/yoki hajmini sozlash orqali erishish mumkin. Ommaviy perovskitlarning hajmini kamaytirish yoki aralash galogenidlarni kiritish orqali ko'k emissiyaga ega uch o'lchovli perovskit nanokristallari muvaffaqiyatli tayyorlandi. Biroq, bunday kichik o'lchamdagi perovskit nanokristallariga asoslangan ko'k elektrolyuminessent qurilmalarning samaradorligi va barqarorligi asosan murakkab tozalash va fazalarni ajratish bilan bog'liq.
Yuqori -samaradorlikdagi koʻk PeLEDlarga erishishning yana bir strategiyasi bir nechta kvant quduqlari boʻlgan kvazi{1}}ikki oʻlchovli (kvazi-2D) perovskit tuzilmalarini qurishdir. Ushbu kvazi-2D perovskitlarning fotoluminesans (PL) xususiyatlari energiyani kichikdan katta n domenga o'tkazish bilan chambarchas bog'liq. Aniqlanishicha, tekis kvazi-2D perovskit kvant quduq kengligi taqsimoti (QWD) tashuvchilarni tashishni osonlashtirish va yuqori samarali fotovoltaik qurilmalarni amalga oshirish uchun qo'shimcha energiya yo'qotilishini kamaytirish uchun zarurdir. Biroq, QWD ning EL qurilmalariga ta'siri kamroq o'rganilgan.
Ma'lumki, QWDni prekursor aralashmalari nisbatini sozlash yoki ligand muhandisligi bilan boshqarish mumkin. Bu erda ikkita ligandlardan foydalanish in situ tayyorlangan CsPbClBr2 nanokristal plyonkalarining QWD ni nazorat qilishning samarali strategiyasi ekanligi ko'rsatilgan. 2-Feniletilamin bromid (PEABr) kichik n domenlarni hosil qilish uchun samarali ligand, 3,3-difenilpropilamin bromid (DPPABr) esa katta n qiymatlarni hosil qilish uchun samarali liganddir. Ikki ligandning nisbatini oqilona tanlash n=4 markaziy hukmronlik bilan QWDni toraytirishi mumkin.
Ushbu samarali o'lcham nazorati energiyani samarali uzatishni osonlashtiradi, natijada 470 nm to'lqin uzunligida kuchli ko'k yorug'lik emissiyasi bilan PL kvant rentabelligi (PLQY) 60 foizga etadi. Kichik n domenlar va katta n domenlarni shakllantirishga moyil bo'lgan ikki tomonlama ligandlardan foydalanish kengaytirilgan PL xususiyatlari uchun tor QWDga erishish uchun ko'p qirrali strategiyadir. PEABr va DPPABr ni aralashtirish orqali tayyorlangan optimallashtirilgan yupqa plyonkalar asosida 473 nm to‘lqin uzunligida maksimal EQE 8,8 foiz bo‘lgan yuqori -samaradorlikdagi ko‘k rangli elektroluminesans qurilmasi olindi. (Matn: Aisin Gioro Star)
1-rasm CsPbClBr2 nanokristalli yupqa plyonkalarning strukturaviy xarakteristikalari. CsPbClBr2 nanokristalli yupqa plyonkalarni-insitu tayyorlash jarayonining sxematik diagrammasi. DPPABr va PEABr ning turli nisbatlariga ega CsPbClBr2 nanokristal plyonkalarining GIWAXS naqshining integral intensivligi q o'rtasidagi bog'liqlik o'rganildi.
2-rasm CsPbClBr2 nanokristalli yupqa plyonkalarning optik o'lchovlari. CsPbClBr2 nanokristal plyonkalarining barqaror-holatdagi fotoluminesans spektrlari, yutilish spektrlari va b-PLQYlari turli DPPABr va PEABr nisbati bilan o‘rganildi.
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.
