TY - JOUR
T1 - Charge Transfer-Induced Molecular Hole Doping into Thin Film of Metal-Organic Frameworks
AU - Lee, Deok Yeon
AU - Kim, Eun Kyung
AU - Shrestha, Nabeen K.
AU - Boukhvalov, Danil W.
AU - Lee, Joong Kee
AU - Han, Sung Hwan
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/8/26
Y1 - 2015/8/26
N2 - Despite the highly porous nature with significantly large surface area, metal-organic frameworks (MOFs) can be hardly used in electronic and optoelectronic devices due to their extremely poor electrical conductivity. Therefore, the study of MOF thin films that require electron transport or conductivity in combination with the everlasting porosity is highly desirable. In the present work, thin films of Co3(NDC)3DMF4 MOFs with improved electronic conductivity are synthesized using layer-by-layer and doctor blade coating techniques followed by iodine doping. The as-prepared and doped films are characterized using FE-SEM, EDX, UV/visible spectroscopy, XPS, current-voltage measurement, photoluminescence spectroscopy, cyclic voltammetry, and incident photon to current efficiency measurements. In addition, the electronic and semiconductor properties of the MOF films are characterized using Hall Effect measurement, which reveals that, in contrast to the insulator behavior of the as-prepared MOFs, the iodine doped MOFs behave as a p-type semiconductor. This is caused by charge transfer-induced hole doping into the frameworks. The observed charge transfer-induced hole doping phenomenon is also confirmed by calculating the densities of states of the as-prepared and iodine doped MOFs based on density functional theory. Photoluminescence spectroscopy demonstrates an efficient interfacial charge transfer between TiO2 and iodine doped MOFs, which can be applied to harvest solar radiations. (Figure Presented).
AB - Despite the highly porous nature with significantly large surface area, metal-organic frameworks (MOFs) can be hardly used in electronic and optoelectronic devices due to their extremely poor electrical conductivity. Therefore, the study of MOF thin films that require electron transport or conductivity in combination with the everlasting porosity is highly desirable. In the present work, thin films of Co3(NDC)3DMF4 MOFs with improved electronic conductivity are synthesized using layer-by-layer and doctor blade coating techniques followed by iodine doping. The as-prepared and doped films are characterized using FE-SEM, EDX, UV/visible spectroscopy, XPS, current-voltage measurement, photoluminescence spectroscopy, cyclic voltammetry, and incident photon to current efficiency measurements. In addition, the electronic and semiconductor properties of the MOF films are characterized using Hall Effect measurement, which reveals that, in contrast to the insulator behavior of the as-prepared MOFs, the iodine doped MOFs behave as a p-type semiconductor. This is caused by charge transfer-induced hole doping into the frameworks. The observed charge transfer-induced hole doping phenomenon is also confirmed by calculating the densities of states of the as-prepared and iodine doped MOFs based on density functional theory. Photoluminescence spectroscopy demonstrates an efficient interfacial charge transfer between TiO2 and iodine doped MOFs, which can be applied to harvest solar radiations. (Figure Presented).
KW - charge transfer complex
KW - Hall Effect measurement
KW - MOFs
KW - molecular hole doping
KW - thin film
UR - http://www.scopus.com/inward/record.url?scp=84940659800&partnerID=8YFLogxK
U2 - 10.1021/acsami.5b04771
DO - 10.1021/acsami.5b04771
M3 - Article
AN - SCOPUS:84940659800
SN - 1944-8244
VL - 7
SP - 18501
EP - 18507
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 33
ER -