TY - JOUR
T1 - Effects of thin film processing on pentacene/C60 bilayer solar cell performance
AU - Yang, Jihua
AU - Nguyen, Thuc Quyen
N1 - Funding Information:
This work is supported by the ONR Young Investigator Program and the UCSB startup fund.
PY - 2007/10
Y1 - 2007/10
N2 - Solar cells based on pentacene/C60 bilayer heterojunctions have been fabricated with a structure of ITO/poly(styrenesulfonate) (PEDOT:PSS)/pentacene (40 nm)/fullerene (C60)(40 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) (10 nm)/Al. The effect of pentacene crystalline domain size on performance was investigated by controlling the pentacene deposition rate. The devices show improved light-to-electricity conversion efficiencies from 0.49% to 1.12% under an AM 1.5 solar simulator (100 mW/cm2), when the pentacene evaporation rate is in a range of 5 Å/s-0.5 Å/s. Atomic force microscopy (AFM) measurements show that the pentacene films deposited by a slow evaporation rate have larger crystalline domains and a fewer amorphous domains, compared to films obtained by faster evaporation rates. Upon thermal annealing at 200 °C for 1 min, there is merging of pentacene crystalline domains. These changes in film morphology impact the charge separation at the donor/acceptor interface and the hole and electron mobilities, and hence, directly affect the device performance.
AB - Solar cells based on pentacene/C60 bilayer heterojunctions have been fabricated with a structure of ITO/poly(styrenesulfonate) (PEDOT:PSS)/pentacene (40 nm)/fullerene (C60)(40 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) (10 nm)/Al. The effect of pentacene crystalline domain size on performance was investigated by controlling the pentacene deposition rate. The devices show improved light-to-electricity conversion efficiencies from 0.49% to 1.12% under an AM 1.5 solar simulator (100 mW/cm2), when the pentacene evaporation rate is in a range of 5 Å/s-0.5 Å/s. Atomic force microscopy (AFM) measurements show that the pentacene films deposited by a slow evaporation rate have larger crystalline domains and a fewer amorphous domains, compared to films obtained by faster evaporation rates. Upon thermal annealing at 200 °C for 1 min, there is merging of pentacene crystalline domains. These changes in film morphology impact the charge separation at the donor/acceptor interface and the hole and electron mobilities, and hence, directly affect the device performance.
KW - C
KW - Film morphology
KW - Film processing
KW - Hole and electron mobilities
KW - Pentacene
KW - Solar cell
KW - Thermal annealing
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U2 - 10.1016/j.orgel.2007.04.005
DO - 10.1016/j.orgel.2007.04.005
M3 - Article
AN - SCOPUS:34548828814
VL - 8
SP - 566
EP - 574
JO - Organic Electronics: physics, materials, applications
JF - Organic Electronics: physics, materials, applications
SN - 1566-1199
IS - 5
ER -