TY  - JOUR
A1  - Kniepert, Juliane
A1  - Lange, Ilja
A1  - Heidbrink, Jan
A1  - Kurpiers, Jona
A1  - Brenner, Thomas J. K.
A1  - Koster, L. Jan Anton
A1  - Neher, Dieter
T1  - Effect of Solvent Additive on Generation, Recombination, and Extraction in PTB7:PCBM Solar Cells: A Conclusive Experimental and Numerical Simulation Study
T2  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - Time-delayed collection field (TDCF), bias-assisted charge extraction (BACE), and space charge-limited current (SCLC) measurements are combined with complete numerical device simulations to unveil the effect of the solvent additive 1,8-diiodooctane (DIO) on the performance of PTB7:PCBM bulk heterojunction solar cells. DIO is shown to increase the charge generation rate, reduce geminate and bimolecular recombination, and increase the electron mobility. In total, the reduction of loss currents by processing with the additive raises the power conversion efficiency of the PTB7:PCBM blend by a factor of almost three. The lower generation rates and higher geminate recombination losses in devices without DIO are consistent with a blend morphology comprising large fullerene clusters embedded within a PTB7-rich matrix, while the low electron mobility suggests that these fullerene clusters are themselves composed of smaller pure fullerene aggregates separated by disordered areas. Our device simulations show unambiguously that the effect of the additive on the shape of the currentvoltage curve (J-V) cannot be ascribed to the variation of only the mobility, the recombination, or the field dependence of generation. It is only when the changes of all three parameters are taken into account that the simulation matches the experimental J-V characteristics under all illumination conditions and for a wide range of voltages.
Y1  - 2015
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/38999
SN  - 1932-7447
VL  - 119
IS  - 15
SP  - 8310
EP  - 8320
PB  - American Chemical Society
CY  - Washington
ER  -