TY - JOUR
T1 - Balancing the electron and hole transfer for efficient quantum dot light-emitting diodes by employing a versatile organic electron-blocking layer
AU - Jin, Xiao
AU - Chang, Chun
AU - Zhao, Weifeng
AU - Huang, Shujuan
AU - Gu, Xiaobing
AU - Zhang, Qin
AU - Li, Feng
AU - Zhang, Yubao
AU - Li, Qinghua
PY - 2018/5/9
Y1 - 2018/5/9
N2 - The electron-blocking layer (EBL) is important to balance the charge carrier transfer and achieve highly efficient quantum dot light-emitting diodes (QLEDs). Here, we report the utilization of a soluble tert-butyldimethylsilyl chloride-modified poly(p-phenylene benzobisoxazole) (TBS-PBO) as an EBL for simultaneous good charge carrier transfer balance while maintaining a high current density. We show that the versatile TBS-PBO blocks excess electron injection into the quantum dots (QDs), thus leading to better charge carrier transfer balance. It also restricts the undesired QD-to-EBL electron-transfer process, which preserves the superior emission capabilities of the emitter. As a consequence, the TBS-PBO device delivers an external quantum efficiency (EQE) maximum of 16.7% along with a remarkable current density as high as 139 mA/cm2 with a brightness of 5484 cd/m2. The current density of our device is higher than those of insulator EBL-based devices because of the higher conductivity of the TBS-PBO versus insulator EBL, thus helping achieve high luminance values ranging from 1414 to 20 000 cd/cm2 with current densities ranging from 44 to 648 mA/cm2 and EQE > 14%. We believe that these unconventional features of the present TBS-PBO-based QLEDs will expand the wide use of TBS-PBO as buffer layers in other advanced QLED applications.
AB - The electron-blocking layer (EBL) is important to balance the charge carrier transfer and achieve highly efficient quantum dot light-emitting diodes (QLEDs). Here, we report the utilization of a soluble tert-butyldimethylsilyl chloride-modified poly(p-phenylene benzobisoxazole) (TBS-PBO) as an EBL for simultaneous good charge carrier transfer balance while maintaining a high current density. We show that the versatile TBS-PBO blocks excess electron injection into the quantum dots (QDs), thus leading to better charge carrier transfer balance. It also restricts the undesired QD-to-EBL electron-transfer process, which preserves the superior emission capabilities of the emitter. As a consequence, the TBS-PBO device delivers an external quantum efficiency (EQE) maximum of 16.7% along with a remarkable current density as high as 139 mA/cm2 with a brightness of 5484 cd/m2. The current density of our device is higher than those of insulator EBL-based devices because of the higher conductivity of the TBS-PBO versus insulator EBL, thus helping achieve high luminance values ranging from 1414 to 20 000 cd/cm2 with current densities ranging from 44 to 648 mA/cm2 and EQE > 14%. We believe that these unconventional features of the present TBS-PBO-based QLEDs will expand the wide use of TBS-PBO as buffer layers in other advanced QLED applications.
KW - quantum dot light-emitting diodes
KW - TBS-PBO
KW - charge-transfer balance
KW - electron-blocking layer
KW - time-resolved PL
UR - http://www.scopus.com/inward/record.url?scp=85046247761&partnerID=8YFLogxK
U2 - 10.1021/acsami.8b00729
DO - 10.1021/acsami.8b00729
M3 - Article
C2 - 29667818
AN - SCOPUS:85046247761
SN - 1944-8244
VL - 10
SP - 15803
EP - 15811
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 18
ER -