TITLE:
Investigation on Lanthanum Fluoride as a Novel Cathode Buffer Material Layer for the Enhancement of Stability and Performance of Organic Solar Cell
AUTHORS:
Md. Shahinul Islam, Md. Golam Saklayen, Md. Ferdous Rahman, Hartmut Baerwolff, Abu Bakar Md. Ismail
KEYWORDS:
Organic Semiconductor, Photoactive Polymer, Organic Solar Cell, Bulk Heterojunction Solar Cells, Cathode Buffer Layer, Lanthanum Fluoride, Spin Coating, E-Beam Evaporation
JOURNAL NAME:
Optics and Photonics Journal,
Vol.4 No.10,
October
16,
2014
ABSTRACT: This
article presents the investigation on very thin Lanthanum Fluoride (LaF3)
layer as a new cathode buffer layer (CBL) for organic solar cell (OSC). OSCs
were fabricated with poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid
methyl ester (PCBM) polymer blend at 1:1 ratio. Electron-beam evaporation at
room temperature was used to deposit 3 and 5 nm thick LaF3 layer. A
very smooth surface of LaF3 with an average roughness of 0.2 nm has
been observed by the Atomic Force Microscope (AFM) that is expected to prevent
diffusion of cathode metal ion through it and thereby enhance the lifetime and
stability of OSC. Huge enhancement of JSC and VOC was
also observed for 3 nm-thick LaF3 CBL. Several excellent features of
the LaF3 layer such as, transporting electron through tunneling,
blocking of holes to the cathode, minimizing recombination, protecting the
photoactive polymer from ambient oxygen, and reducing degradation/oxidation of
any low work function layer at the cathode interface, might have contributed to
the performance enhancement of OSC. The experimental findings indicate the
promise of LaF3 to be an excellent CBL material for OSC.