Induced Infiltration of Hole-Transporting Polymer into Photocatalyst for Staunch Polymer-Metal Oxide Hybrid Solar Cells.
For efficient solar cells based on organic semiconductors, a good mixture of photoactive materials in the bulk heterojunction on the length scale of several tens of nanometers is an important requirement to prevent exciton recombination. Herein, we demonstrate that nanoporous titanium dioxide inverse opal structures fabricated using a self-assembled monolayer method and with enhanced infiltration of electron-donating polymers is an efficient electron-extracting layer, which enhances the photovoltaic performance. A calcination process generates an inverse opal structure of titanium dioxide (<70 nm of pore diameters) providing three-dimensional (3D) electron transport pathways. Hole-transporting polymers was successfully infiltrated into the pores of the surface-modified titanium dioxide under vacuum conditions at 200 °C. The resulting geometry expands the interfacial area between hole- and electron-transport materials, increasing the thickness of the active layer. The controlled polymer-coating process over titanium dioxide materials enhanced photocurrent of the solar cell device. Density functional theory calculations show improved interfacial adhesion between the self-assembled monolayer-modified surface and polymer molecules, supporting the experimental result of enhanced polymer infiltration into the voids. These results suggest that the 3D inverse opal structure of the surface-modified titanium dioxide can serve as a favorable electron-extracting layer in further enhancing optoelectronic performance based on organic or organic-inorganic hybrid solar cell.
Department of Chemical Engineering, Pohang University of Science and Technology , 77 Cheongam-Ro. Nam-Gu. Pohang. Gyeongbuk 37673, Republic of Korea.
Jong Hwan
JH
Park
Department of Chemistry, Seoul National University , Gwanak-ro 1, Gwanak-gu, Seoul 08826, Republic of Korea.
Youngsuk
Y
Jung
School of Chemical and Biological Engineering, Seoul National University , Gwanak-ro 1, Gwanak-gu, Seoul 08826, Republic of Korea.
Yooseong
Y
Yang
Department of Civil and Environmental Engineering, Pusan National University , 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 46241, Republic of Korea.
Hyun Suk
HS
Shin
Department of Civil and Environmental Engineering, Pusan National University , 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 46241, Republic of Korea.
Soonchul
S
Kwon
3D inverse opal structures; hole-transporting polymer; polymer infiltration; solar cell; titanium dioxide