TY  - JOUR
A1  - Armin, Ardalan
A1  - Chen, Zhiming
A1  - Jin, Yaocheng
A1  - Zhang, Kai
A1  - Huang, Fei
A1  - Shoaee, Safa
T1  - A Shockley-Type polymer
BT  - Fullerene solar cell
JF  - Advanced energy materials
N2  - Charge extraction rate in solar cells made of blends of electron donating/accepting organic semiconductors is typically slow due to their low charge carrier mobility. This sets a limit on the active layer thickness and has hindered the industrialization of organic solar cells (OSCs). Herein, charge transport and recombination properties of an efficient polymer (NT812):fullerene blend are investigated. This system delivers power conversion efficiency of >9% even when the junction thickness is as large as 800 nm. Experimental results indicate that this material system exhibits exceptionally low bimolecular recombination constant, 800 times smaller than the diffusion-controlled electron and hole encounter rate. Comparing theoretical results based on a recently introduced modified Shockley model for fill factor, and experiments, clarifies that charge collection is nearly ideal in these solar cells even when the thickness is several hundreds of nanometer. This is the first realization of high-efficiency Shockley-type organic solar cells with junction thicknesses suitable for scaling up.
KW  - charge transport
KW  - non-Langevin recombination
KW  - organic solar cells
KW  - thick junctions
Y1  - 2018
U6  - https://doi.org/10.1002/aenm.201701450
SN  - 1614-6832
SN  - 1614-6840
VL  - 8
IS  - 7
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Zhang, Kai
A1  - Chen, Zhiming
A1  - Armin, Ardalan
A1  - Dong, Sheng
A1  - Xia, Ruoxi
A1  - Yip, Hin-Lap
A1  - Shoaee, Safa
A1  - Huang, Fei
A1  - Cao, Yong
T1  - Efficient large area organic solar cells processed by blade-coating with single-component green solvent
JF  - Solar Rrl
N2  - While the performance of laboratory-scale organic solar cells (OSCs) continues to grow, development of high efficiency large area OSCs remains a big challenge. Although a few attempts to produce large area organic solar cells (OSCs) have been reported, there are still challenges on the way to realizing efficient module devices, such as the low compatibility of the thickness-sensitive active layer with large area coating techniques, the frequent need for toxic solvents and tedious optimization processes used during device fabrication. In this work, highly efficient thickness-insensitive OSCs based on PTB7-Th:PC71BM that processed with single-component green solvent 2-methylanisole are presented, in which both junction thickness limitation and solvent toxicity issues are simultaneously addressed. Careful investigation reveals that this green solvent prevents the evolution of PC71BM into large area clusters resulting in reduced charge carrier recombination, and largely eliminates trapping centers, and thus improves the thickness tolerance of the films. These findings enable us to address the scalability and solvent toxicity issues and to fabricate a 16 cm(2) OSC with doctor-blade coating with a state-of-the-art power conversion efficiency of 7.5% using green solvent.
KW  - doctor-blade coating
KW  - green solvents
KW  - large area devices
KW  - organic solar cells
KW  - thickness insensitive active layers
Y1  - 2017
U6  - https://doi.org/10.1002/solr.201700169
SN  - 2367-198X
VL  - 2
IS  - 1
PB  - Wiley-VCH
CY  - Weinheim
ER  -