Quadrupole Moment Induced Morphology Control Via a Highly Volatile Small Molecule in Efficient Organic Solar Cells

Abstract

Developing novel solid additives has been regarded as a promising strategy to achieve highly efficient organic solar cells with good stability and reproducibility. Herein, a small molecule, 2,2′-(perfluoro-1,4-phenylene)dithiophene (DTBF), designed with high volatility and a strong quadrupole moment, is applied as a solid additive to implement active layer morphology control in organic solar cells. Systematic theory simulations have revealed the charge distribution of DTBF and its analog and their non-covalent interaction with the active layer materials. Benefitting from the more vital charge-quadrupole interaction, the introduction, and volatilization of DTBF effectively induced more regular and condensed molecular packing in the active layer, leading to enhanced photoelectric properties. Thus, high efficiency of over 17% is obtained in the DTBF-processed devices, which is higher than that of the control devices. Further application of DTBF in different active layer systems contributed to a deeper comprehension of this type of additive. This study highlights a facile approach to optimizing the active layer morphology by finely manipulating the quadrupole moment of volatile solid additives.

Achieving over 10 % Efficiency in Poly(3‐hexylthiophene)‐Based Organic Solar Cells via Solid Additives

“…Furthermore, some other volatilizable solid additives named SA1, [35] DTBF, and DTB, [41] were also applied to process P3HT:ZY-4Cl-based OSCs. As shown in Figure S9 and Table S1, all these solid additives can effectively improve the device performance with increased PCEs of 9.66, 9.73, and 9.45 % for SA1-, DTBF-, and DTB-processed devices, respectively, implying the suitability of solid additives for non-fullerene P3HT-based OSCs.…”

Simultaneously Enhanced Efficiency and Operational Stability of Nonfullerene Organic Solar Cells via Solid‐Additive‐Mediated Aggregation Control

“…Solid additive is an emerging approach to solve this problem. [ 48–52 ] The solid additive presents during the solution‐casting process of the photoactive layer to manipulate the molecular stacking and structural ordering, [ 53,54 ] but the temperatures to drive them evaporating from the solid active layer are usually moderate around 100 °C, making them ideal materials to prepare high‐performance additive‐free OSCs, although their volatility is not essential toward performance improvement. [ 49,53,55 ] For example, SA‐4, a solid additive synthesized by Yu et al., could regulate the ordered arrangement and π‐π stacking of NFA molecules, increasing the PCE of poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐chloro)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione)] (PBDB‐T‐2Cl or PM7):9‐Bis(2‐methylene‐((3‐(1,1‐dicyanomethylene)‐6,7‐difluoro)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno2,3‐d:2′,3′‐d′‐s‐indaceno1,2‐b:5,6‐b′dithiophene (IT‐4F) OSCs from 12.1% to 13.5%.…”

Understanding the molecular mechanisms of the differences in the efficiency and stability of all-polymer solar cells

“…This result indicates that the PM6:PYT-M system possesses a lower trap-assisted recombination loss as compared with the other two all-polymer systems based on PYT-M as the acceptor. 47 Fig. 3D further exhibits the V OC -ln(P light ) relationship for the PYT-H-based all-polymer systems at various light intensities.…”