TY - JOUR
T1 - Tuning molecule diffusion to control the phase separation of the
T2 - P -DTS(FBTTh2)2/EP-PDI blend system via thermal annealing
AU - Liang, Qiuju
AU - Han, Jie
AU - Song, Chunpeng
AU - Wang, Zaiyu
AU - Xin, Jingming
AU - Yu, Xinhong
AU - Xie, Zhiyuan
AU - Ma, Wei
AU - Liu, Jiangang
AU - Han, Yanchun
N1 - Publisher Copyright:
© The Royal Society of Chemistry 2017.
PY - 2017
Y1 - 2017
N2 - An interpenetrating bulk-heterojunction structure with a domain size of 10-20 nm is the ideal morphology for carrier generation, separation and transportation in organic solar cells. However, depending on the blend composition, the phase-separation behavior of the crystalline small molecule blend system of donor 7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl)bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2) and acceptor N,N′-bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxylic diimide (EP-PDI) is quite different. When the weight ratio of p-DTS(FBTTh2)2/EP-PDI is greater than 8:2 or smaller than 4:6, a large phase separation structure is observed induced by p-DTS(FBTTh2)2 or EP-PDI crystallization. When the ratio of p-DTS(FBTTh2)2:EP-PDI changes from 7:3 to 5:5, no obvious phase separation can be detected due to the interaction between p-DTS(FBTTh2)2 and EP-PDI. In order to obtain the interpenetrating bulk-heterojunction structure with a domain size of 10-20 nm, we proposed to tune the molecule diffusion of p-DTS(FBTTh2)2 and EP-PDI by different thermal annealing temperature to control the phase separation domain size and phase purity. When the annealing temperature is T < Tm EP-PDI + Ta or T > Tc p-DTS(FBTTh2)2 - Tb (T is the thermal annealing temperature, Ta and Tb are constants), the molecule diffusion rate of both p-DTS(FBTTh2)2 and EP-PDI is too slow or too fast, resulting in no phase separation or large phase separation morphology. When T is between Tm EP-PDI + Ta and Tc p-DTS(FBTTh2)2 - Tb, EP-PDI is in a melting state, but p-DTS(FBTTh2)2 self-assembles into crystals. As a result, p-DTS(FBTTh2)2 crystallized and formed a framework, which inhibited the massive crystallization of EP-PDI due to the spatial confinement of the p-DTS(FBTTh2)2 crystallization framework, leading to the formation of a bi-continuous phase separation structure with suitable domain size and phase purity. Based on the above phase separation structure we got, a power conversion efficiency of 4.25% was obtained, which is relatively high in this system without any additives.
AB - An interpenetrating bulk-heterojunction structure with a domain size of 10-20 nm is the ideal morphology for carrier generation, separation and transportation in organic solar cells. However, depending on the blend composition, the phase-separation behavior of the crystalline small molecule blend system of donor 7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl)bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2) and acceptor N,N′-bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxylic diimide (EP-PDI) is quite different. When the weight ratio of p-DTS(FBTTh2)2/EP-PDI is greater than 8:2 or smaller than 4:6, a large phase separation structure is observed induced by p-DTS(FBTTh2)2 or EP-PDI crystallization. When the ratio of p-DTS(FBTTh2)2:EP-PDI changes from 7:3 to 5:5, no obvious phase separation can be detected due to the interaction between p-DTS(FBTTh2)2 and EP-PDI. In order to obtain the interpenetrating bulk-heterojunction structure with a domain size of 10-20 nm, we proposed to tune the molecule diffusion of p-DTS(FBTTh2)2 and EP-PDI by different thermal annealing temperature to control the phase separation domain size and phase purity. When the annealing temperature is T < Tm EP-PDI + Ta or T > Tc p-DTS(FBTTh2)2 - Tb (T is the thermal annealing temperature, Ta and Tb are constants), the molecule diffusion rate of both p-DTS(FBTTh2)2 and EP-PDI is too slow or too fast, resulting in no phase separation or large phase separation morphology. When T is between Tm EP-PDI + Ta and Tc p-DTS(FBTTh2)2 - Tb, EP-PDI is in a melting state, but p-DTS(FBTTh2)2 self-assembles into crystals. As a result, p-DTS(FBTTh2)2 crystallized and formed a framework, which inhibited the massive crystallization of EP-PDI due to the spatial confinement of the p-DTS(FBTTh2)2 crystallization framework, leading to the formation of a bi-continuous phase separation structure with suitable domain size and phase purity. Based on the above phase separation structure we got, a power conversion efficiency of 4.25% was obtained, which is relatively high in this system without any additives.
UR - https://www.scopus.com/pages/publications/85024375753
U2 - 10.1039/c7tc01763d
DO - 10.1039/c7tc01763d
M3 - 文章
AN - SCOPUS:85024375753
SN - 2050-7534
VL - 5
SP - 6842
EP - 6851
JO - Journal of Materials Chemistry C
JF - Journal of Materials Chemistry C
IS - 27
ER -