Enhancement of Performance and Mechanism Studies of All-Solution Processed Small-Molecule based Solar Cells with an Inverted Structure.
Both solution-processed polymers and small molecule based solar cells have achieved PCEs over 9% with the conventional device structure. However, for the practical applications of photovoltaic technology, further enhancement of both device performance and stability are urgently required, particularly for the inverted structure devices, since this architecture will probably be most promising for the possible coming commercialization. In this work, we have fabricated both conventional and inverted structure devices using the same small molecular donor/acceptor materials and compared the performance of both device structures, and found that the inverted structure based device gave significantly improved performance, the highest PCE so far for inverted structure based device using small molecules as the donor. Furthermore, the inverted device shows a remarkable stability with almost no obvious degradation after three months. Systematic device physics and charge generation dynamics studies, including optical simulation, light-intensity-dependent current-voltage experiments, photocurrent density-effective voltage analyses, transient absorption measurements, and electrical simulations, indicate that the significantly enhanced performance using inverted device is ascribed to the increasing of Jsc compared to the conventional device, which in turn is mainly attributed to the increased absorption of photons in the active layers, rather than the reduced nongeminate recombination.
State Key Laboratory and Institute of Elemento-Organic Chemistry and Centre for Nanoscale Science and Technology, Institute of Polymer Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University , Tianjin, 300071, China.
Guankui
G
Long
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, 637371, Singapore.|Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE), 1 Create Way, Singapore 138602, Singapore.
Bo
B
Wu
State Key Laboratory and Institute of Elemento-Organic Chemistry and Centre for Nanoscale Science and Technology, Institute of Polymer Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University , Tianjin, 300071, China.
Xuan
X
Yang
State Key Laboratory and Institute of Elemento-Organic Chemistry and Centre for Nanoscale Science and Technology, Institute of Polymer Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University , Tianjin, 300071, China.
Bin
B
Kan
State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou, 730000, China.
Ye-Cheng
YC
Zhou
State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou, 730000, China.
Li-Chuan
LC
Chen
State Key Laboratory and Institute of Elemento-Organic Chemistry and Centre for Nanoscale Science and Technology, Institute of Polymer Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University , Tianjin, 300071, China.
Xiangjian
X
Wan
State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou, 730000, China.
Hao-Li
HL
Zhang
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, 637371, Singapore.
Tze Chien
TC
Sum
State Key Laboratory and Institute of Elemento-Organic Chemistry and Centre for Nanoscale Science and Technology, Institute of Polymer Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University , Tianjin, 300071, China.
Yongsheng
Y
Chen
electrical simulation; inverted device; organic photovoltaic; small molecules; transient absorption spectra